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Don J
2013-Apr-09, 07:47 PM
Maybe Levin was right after all.
http://news.nationalgeographic.com/news/2008/06/080626-mars-lander.html


Soil near the north pole of Mars is surprisingly Earthlike, with a pH not unlike many vegetable gardens, according to preliminary results from the Phoenix Mars Lander.

"You might be able to grow asparagus in it, but strawberries, probably not very well," said Samuel Kounaves, a chemistry professor at Tufts University, during a NASA press conference this afternoon.

Previous data from the two rovers exploring Mars's equatorial zones had suggested that the geochemistry on the red planet might have been too acidic to support most forms of Earth-type life.

But as little as an inch (2.5 centimeters) beneath the surface, dirt from Mars's arctic plains proved to be very similar to alkaline soils on Earth, with a pH between 8 and 9. The pH scale goes from 0 (acidic) to 14 (alkaline).

But unfortunately Phoenix was not equipped with equipment to detect organics compounds...so it is not surprising that...-While these are all key nutrients, the tests don't reveal everything needed for life.-


The MECA team also found that the soil contains magnesium, sodium, potassium, and chloride.

While these are all key nutrients, the tests don't reveal everything needed for life.

For example, the test looked only at inorganic nutrients, not organic compounds, and it didn't look at all of the dozens of potentially important trace nutrients.


Still, said MECA team leader Michael Hecht of NASA's Jet Propulsion Laboratory, "it's a huge step forward."

Note that Levin suggested a little modification of one of the instrument who may have been able to detect organic compounds. But Levin modification proposal was not taken into account.
see page 8 of the PDF.
http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf

kzb
2013-Apr-16, 11:57 AM
Interested to hear on UK Radio 4 this morning that Heather Cooper (an astronomer familiar to UK TV viewers) believes there is almost certainly primitive life on Mars.

My viewpoint (for what it's worth) has changed over the years, and now I think it'd be more surprising if Mars does NOT have life. I think the key turning point was when I read that Antarctic soil (known to contain a sparse population of antarctic bacteria) gave exactly the same pattern of results as the Viking Mars soil tests.

Don J
2013-Apr-20, 03:24 AM
My viewpoint (for what it's worth) has changed over the years, and now I think it'd be more surprising if Mars does NOT have life. I think the key turning point was when I read that Antarctic soil (known to contain a sparse population of antarctic bacteria) gave exactly the same pattern of results as the Viking Mars soil tests.
I am still convinced that one or two robotic missions for collecting samples at the two landing Viking site would have been of great interest.But they rather chosed -to reject the Viking's positive life detection results- and send probes and rovers on Mars not even equipped with instruments to detect life as pointed out in the article....and by Levin in the PDF document.

However there may be a danger of contamination with a sample-and-return mission of biological active microorganisms from the Martian soil ...so it is probably a good thing that no sample-and-return mission of the Martian soil was ever planned and executed...
http://www.space.com/209-life-mars-scientist-claims.html
Excerpts:


If indeed Mars is rife with life, care should be taken in hauling back to Earth specimens of rock and surface materials from the red planet. NASA has indicated that, next decade, robotic craft could be dispatched to gather and return to Earth select samples of Mars for detailed laboratory study.

Could those bits of Mars, perhaps laden with martian microbes, act as dangerous cargo?

As a precaution, Levin advocates a kind of bio-shield strategy for Earth - but using the Moon.

The new NASA vision to reestablish a human presence on the Moon is good timing, Levin said. "Bring samples of Mars not to Earth but to the Moon," he said. "There we would have built a scientific laboratory in which scientists could examine the samples and determine whether or not there is a hazard."

Don J
2013-Apr-21, 03:00 AM
I could be wrong but it seem that there was no missions to Mars after Viking(s) who have the scientific instruments needed to detect life ?

cjameshuff
2013-Apr-21, 02:13 PM
I am still convinced that one or two robotic missions for collecting samples at the two landing Viking site would have been of great interest.But they rather chosed -to reject the Viking's positive life detection results- and send probes and rovers on Mars not even equipped with instruments to detect life as pointed out in the article....and by Levin in the PDF document.

We already have some observations from those locations. It's unlikely our first two probes happened to land at the only sites with evidence of life, and there are other likely-looking locations. It's reasonable at this point to scatter our probes widely to get a good idea what the planet as a whole looks like, we might miss something important by focusing all our efforts on one specific area.



I could be wrong but it seem that there was no missions to Mars after Viking(s) who have the scientific instruments needed to detect life ?

Similarly, its reasonable to try and get an overview of the environment before making another attempt at designing tests for life.

neilzero
2013-Apr-21, 02:34 PM
Possibly "they" decided that we don't know how to build life detecting instruments even for Earth type life. Such conclusions tend to be kept secret especially if "they" spoke with confidence earlier. Neil

Don J
2013-Apr-21, 06:19 PM
Possibly "they" decided that we don't know how to build life detecting instruments even for Earth type life. Such conclusions tend to be kept secret especially if "they" spoke with confidence earlier. Neil
I think the how to build life detecting instruments was adequately solved and used in the Viking mission.
See
http://www.gillevin.com/Mars/Reprint49_files/Reprint49.htm

Don J
2013-Apr-21, 06:26 PM
We already have some observations from those locations. It's unlikely our first two probes happened to land at the only sites with evidence of life, and there are other likely-looking locations. It's reasonable at this point to scatter our probes widely to get a good idea what the planet as a whole looks like, we might miss something important by focusing all our efforts on one specific area.

Similarly, its reasonable to try and get an overview of the environment before making another attempt at designing tests for life.

Note that the two Viking probes where located at 4,000 miles from each other and that both detected microorganisms life.

cjameshuff
2013-Apr-21, 06:55 PM
But the instruments for detecting life already existed since the Viking mission.

No they didn't. They still don't exist.



So, why not sending probes equipped with life detection instruments in those other aera?

Viking detected activity that may have just been due to reactive chemicals. A capable biology lab that could give an unambiguous result would be a substantial piece of instrumentation, costly to develop and send and taking up room that might be better used for other instruments. It doesn't make sense to send one blindly.

cjameshuff
2013-Apr-21, 06:58 PM
Note that the two Viking probes where located at 4,000 miles from each other and that both detected microorganisms life.

No, they gave ambiguous results possibly consistent with microbial life. If they gave clear evidence of life, we'd have a lot more on Mars by now.

Don J
2013-Apr-21, 07:16 PM
But the instruments for detecting life already existed since the Viking mission.
No they didn't. They still don't exist.

Here the instruments tested on Earth and used by Viking on Mars.
http://www.gillevin.com/Mars/Reprint49_files/Reprint49.htm


Viking detected activity that may have just been due to reactive chemicals.

Levin discuss and provide good arguments against that explanation put forward to reject the positive life detection results with graph obtained from Viking and test made with samples of Earth soil from different locations.The positive life detection result from the Mars soil samples are very similar to the pattern obtained from samples taken in Antarctic.. as pointed out by kzb in post 2 -Antarctic soil (known to contain a sparse population of antarctic bacteria) gave exactly the same pattern of results as the Viking Mars soil tests. - (working link)
http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf

Ara Pacis
2013-Apr-25, 09:14 PM
Why not send a microscope capable of seeing bacteria on a robotic explorer?

cjameshuff
2013-Apr-25, 09:25 PM
Why not send a microscope capable of seeing bacteria on a robotic explorer?

Complexities of robotically preparing specimens, for example. You can't just shovel some dirt under the microscope. Extremophiles are unlikely to be large enough to see with a simple system, and a complex system would be expensive, risky, bulky, and would have a limited number of chances for analysis with low probability of any of them succeeding...especially if you don't spend some time beforehand to look for particularly likely places, hopefully with some chemical evidence of biological material.

Ara Pacis
2013-Apr-26, 06:02 AM
Complexities of robotically preparing specimens, for example. You can't just shovel some dirt under the microscope. Extremophiles are unlikely to be large enough to see with a simple system, and a complex system would be expensive, risky, bulky, and would have a limited number of chances for analysis with low probability of any of them succeeding...especially if you don't spend some time beforehand to look for particularly likely places, hopefully with some chemical evidence of biological material.

I know, but... So? Why not. Certain space exploration types try to convince us that robots can do everything, so let them make a robot that can do everything.

publiusr
2013-Apr-26, 09:21 PM
Might make a nice place for a greenhouse.

cjameshuff
2013-Apr-27, 03:26 AM
I know, but... So? Why not. Certain space exploration types try to convince us that robots can do everything, so let them make a robot that can do everything.

Because it's more expensive, would take longer to develop, and would take up room that could be devoted to instruments more likely to produce results. Sending a biological microscopy lab along with every probe would not be cheap, nor would it be the best use of resources even if we had the funding for it. It might not even be the best robotic approach...a sample return mission would allow a much more detailed analysis to be done.

Ara Pacis
2013-Apr-27, 02:17 PM
Because it's more expensive, would take longer to develop, and would take up room that could be devoted to instruments more likely to produce results. Sending a biological microscopy lab along with every probe would not be cheap, nor would it be the best use of resources even if we had the funding for it. It might not even be the best robotic approach...a sample return mission would allow a much more detailed analysis to be done.

Sure, if you have better equipment, then send that instead. Just make the rover able to answer the question definitively.

cjameshuff
2013-Apr-27, 02:39 PM
Sure, if you have better equipment, then send that instead. Just make the rover able to answer the question definitively.

Are you paying any attention at all to what I'm saying? There is no magic "detect life on planet" box that you can grab from Radio Shack and bolt onto the rover. A biological microscope's not going to do you any good if you land in the middle of a plain of corrosive salts. There's limited mass and volume and limited funding and development time for instruments, you can't carry everything.

If we required that a Mars mission be able to do what you want, we'd never launch, whether it was an orbiter, stationary lander, rover, or full-blown manned mission. How would that be an improvement?

Ara Pacis
2013-Apr-27, 04:07 PM
Are you paying any attention at all to what I'm saying? There is no magic "detect life on planet" box that you can grab from Radio Shack and bolt onto the rover. A biological microscope's not going to do you any good if you land in the middle of a plain of corrosive salts. There's limited mass and volume and limited funding and development time for instruments, you can't carry everything.

If we required that a Mars mission be able to do what you want, we'd never launch, whether it was an orbiter, stationary lander, rover, or full-blown manned mission. How would that be an improvement?

Are you paying attention to what I'm saying. If we can't send a rover to do it, then perhaps we need to send something else that can.

Wait, are you saying that even a full blown manned mission wouldn't be able to detect life on mars? Somehow manned mission manage to do it on Earth.

cjameshuff
2013-Apr-27, 05:25 PM
Are you paying attention to what I'm saying. If we can't send a rover to do it, then perhaps we need to send something else that can.

Wait, are you saying that even a full blown manned mission wouldn't be able to detect life on mars? Somehow manned mission manage to do it on Earth.

More "argument by ignoring explanations". You're really got to break that habit.

Ronald Brak
2013-Apr-28, 01:01 AM
Everybody will probably hate me forever for mentioning this, but labs on earth are preparing an increasing amount of samples robotically.

cjameshuff
2013-Apr-28, 01:36 AM
Everybody will probably hate me forever for mentioning this, but labs on earth are preparing an increasing amount of samples robotically.

Yeah, but the equipment's generally not designed for shipment to another planet and independent operation far from any source of resupply. You can't just order new glassware or reagents. Even if it were, you can't pack an entire fully-equipped biological and chemical lab into a 900 kg Mars rover, and sending people along doesn't make it any easier to deliver all the equipment and materials.

Ara Pacis' question has been answered. To repeat: it would be more costly and would take longer to develop, and would still not be certain to detect life. There is no magical life-detector box, a human with a minimalist mobile laboratory certainly isn't such a thing...about the most important thing humans could do is sample collection and selection for transport back to Earth where they can be sent to fully-equipped laboratories, not on-the-spot analysis. The probes we've sent are telling us what we need to know to design and target more sophisticated probes and manned missions. If we made it a requirement that the mission be "able to answer the question definitively", we'd simply never send anything, as nothing we could send would actually do the job.

Selfsim
2013-Apr-28, 06:48 AM
Exo-life detection will depend primarily on the macro nature of a 'sample of interest', (or some fluke encounter).

Eliminating other plausible explanations for observations derived from some sample, requires direct data from the environment from which that sample was sourced. In Earth's case, we have myriads of accumulated environmental data to draw from, in order to eliminate measurements caused by non-living environmental factors ... this is not necessarily so in a non-Earth environment however ... so the gathering of this type data would be the first step.

Microscopes? Why should we assume that exo-life someplace would be microscopic bacteria?
Regardless of such beliefs, Curiosity does have some kind of magnification optics aboard (for examining/characterising geological/mineral structures). The X-Ray diffraction imager would also pick up remnants of Earth-like organic by-products.

The decision about sending humans depends on task complexity. The task complexity requires justification from some prior in-situ data gathering expedition.

The curious aspect is that this term 'organic compound' is extremely flexible and pliable. The only reason 'bio-organic compounds' on Earth are called '(bio)organic compounds', is because life, which we know exists here, (in abundance), consumes, produces and functions on these ... so we call them 'organic compounds'. The same chemicals found elsewhere doesn't mean much, unless they're accompanied by some other macro indicator of extant life metabolism (etc) ... eg: some 'green goo' or something.

Ara Pacis
2013-Apr-28, 07:57 PM
More "argument by ignoring explanations". You're really got to break that habit.

If your arguments were on point instead of being strawmen (or an appeal to athority -yours) then they wouldn't get ignored.


Yeah, but the equipment's generally not designed for shipment to another planet and independent operation far from any source of resupply. You can't just order new glassware or reagents. Even if it were, you can't pack an entire fully-equipped biological and chemical lab into a 900 kg Mars rover, and sending people along doesn't make it any easier to deliver all the equipment and materials.

Why limit a rover to 900 kg? How does sending people in a mission (under the assumption that the humans and their support equipment will mass over 900 kg) not increase the economy of scale such that it would support sending equipment and materials suitable for answering the question? Is the equipment that much less robust than a human that it cuoldn't survive the accelerations?


Ara Pacis' question has been answered. To repeat: it would be more costly and would take longer to develop, and would still not be certain to detect life. There is no magical life-detector box, a human with a minimalist mobile laboratory certainly isn't such a thing...about the most important thing humans could do is sample collection and selection for transport back to Earth where they can be sent to fully-equipped laboratories, not on-the-spot analysis. The probes we've sent are telling us what we need to know to design and target more sophisticated probes and manned missions. If we made it a requirement that the mission be "able to answer the question definitively", we'd simply never send anything, as nothing we could send would actually do the job.

While all answers are responses, not all responses are answers. How will designing and targeting more sophisticated probes and/or manned missions help us answer the question, or do you mean only via sample return to earth?

FarmMarsNow
2013-Apr-28, 11:38 PM
Its not definitive, but it should be possible to send a synthetic olfactory sensor with a rover. It would be small, and it might be very useful for finding interesting sites or even detecting life signs. It is a rover after all.

neilzero
2013-Apr-29, 12:29 AM
A brain/computer interface for a one kilogram dog. Some dogs have very advanced oder analysis, and one kilogram should be much easier life support than a 60 kilogram human. Neil

ASTRO BOY
2013-Apr-29, 03:24 AM
Exo-life detection will depend primarily on the macro nature of a 'sample of interest', (or some fluke encounter).



Microscopes? Why should we assume that exo-life someplace would be microscopic bacteria?
Regardless of such beliefs, Curiosity does have some kind of magnification optics aboard (for examining/characterising geological/mineral structures). The X-Ray diffraction imager would also pick up remnants of Earth-like organic by-products.

The decision about sending humans depends on task complexity. The task complexity requires justification from some prior in-situ data gathering expedition.



Why would we assume exo-life would be microscopic?
I would imagine we would assume that if the planet concerned had conditions that would be described as harsh and near our known borderline of where we would assume life could exist...eg: The surface of Mars cannot support liquid water for any length of time.
I would imagine then that the search for life on Mars would be bacterial and microscopic and probably beneath the surface to boot. The search for the most basic of life would be the most logical to undertake in the first place.
It would also be the form of life most numerous throughout the Universe due to the lack of complexity when compared to the more complex and larger lifeforms.
That's not to say that exo-bacterial life will be the first to be found...But the probability of it being far more numerous certainly gives it odds on favourite status.

The decision about sending humans???
Humans in time will be sent anyway, whether we find any exo-life or not.
It's basically an old human condition to explore and go where no man has gone before.

FarmMarsNow
2013-Apr-29, 08:39 AM
A brain/computer interface for a one kilogram dog. Some dogs have very advanced oder analysis, and one kilogram should be much easier life support than a 60 kilogram human. Neil Yes and a robotic collar to make sure the dog minds its duties.

Selfsim
2013-Apr-29, 11:27 PM
Hmm .. I think most measures of comparative 'organism complexity' in a given habitat, (as far as information goes), is reasonably correlated with:

i) how many phases a given organism transitions through, as it matures over its own development/life cycle;
ii) the numbers of adaptations it has gone through over its evolutionary development;
iii) (perhaps) its trophic level in a given ecosystem (which is related to how it sources its energy requirements);
iv) the degree of horizontal gene transference the species has undergone;
v) etc, etc.

Now why any of that would set expectations of 'increased probability' (or numeracy) in an environment measured by Earth's standards as an 'extremophile environment', elsewhere throughout the universe? This 'logic' requires a huge explanation.

Could it be that just because we can't see little green people running around building space probes, telescopes, LHCs, etc in our own Solar System, we've assumed that evolution on say Mars, has resulted in only sub-surface bacteria? If so, where are the 'more complex' predators? Why are they not visible? Why would an ecological pyramid not have evolved which results in bigger, more 'complex' predators? Why should we assume bacteria would survive over Mars' lifetime, without the known healthy influences of higher trophic levels in its (presumed) own eco-system?

Colin Robinson
2013-Apr-30, 09:03 AM
Hmm .. I think most measures of comparative 'organism complexity' in a given habitat, (as far as information goes), is reasonably correlated with:

i) how many phases a given organism transitions through, as it matures over its own development/life cycle;
ii) the numbers of adaptations it has gone through over its evolutionary development;
iii) (perhaps) its trophic level in a given ecosystem (which is related to how it sources its energy requirements);
iv) the degree of horizontal gene transference the species has undergone;
v) etc, etc.

Now why any of that would set expectations of 'increased probability' (or numeracy) in an environment measured by Earth's standards as an 'extremophile environment', elsewhere throughout the universe? This 'logic' requires a huge explanation.

Could it be that just because we can't see little green people running around building space probes, telescopes, LHCs, etc in our own Solar System, we've assumed that evolution on say Mars, has resulted in only sub-surface bacteria? If so, where are the 'more complex' predators? Why are they not visible? Why would an ecological pyramid not have evolved which results in bigger, more 'complex' predators? Why should we assume bacteria would survive over Mars' lifetime, without the known healthy influences of higher trophic levels in its (presumed) own eco-system?

Bacteria and other microbes can certainly have a healthy eco-system without "the known healthy influence of higher trophic levels". Right here on Earth, for about 3 billion years the eco-system consisted of microbes only. The Cambrian explosion, which gave rise to those "higher trophic levels" was a mere half billion years ago — a very recent experiment, whose long-term viability remains uncertain.

Selfsim
2013-Apr-30, 10:40 AM
Bacteria and other microbes can certainly have a healthy eco-system without "the known healthy influence of higher trophic levels". Right here on Earth, for about 3 billion years the eco-system consisted of microbes only. The Cambrian explosion, which gave rise to those "higher trophic levels" was a mere half billion years ago — a very recent experiment, whose long-term viability remains uncertain.So Mars is about the same age as Earth. If life in the form of bacteria developed on Mars in the past, then why would it just stop at bacterial levels?

Whilst the causes of the Earth's so-called 'Cambrian Explosion' have never been shown to be clear-cut, theories covering the emergence of species complexity turn out to be an inseparable mixture of ecological, environmental, developmental (evolutionary genetics) and complexity thresholding. I would have thought Mars would not be excluded from any of these so-called 'universal' phenomena? If not, then why would we prefer searches for bacteria? After all, I thought 'once life gets started', its evolution is inevitable as far as Astrobiology is concerned?

This' bacteria boundary' seems to be more like a mental block than any logical consequence of any current evidenced-based theories.

Why is Mars being treated as a pariah planet by our faithful and intrepid exo-life hunters?

neilzero
2013-Apr-30, 12:41 PM
Because of what we know already about present Mars surface conditions, we think previous life on Mars (if any) could presently only survive several meters or more below the surface without advanced technology. We have not searched significantly below the surface of off world bodies, but we have found some fosils, but we were unable determine if they were ever living.
I suppose there is a minute possibity of high tech Martians presently living beneath the surface who have choosen to avoid contact with our rovers, or even high tech Martians living on the surface in locations we have not explored yet = about 99% of the surface area of Mars.
My guess is simple life forms do not evolve into higher life forms, that survive, unless there is a viable environmental niche for higher life forms.
Possibly some of what Selfism typed is minority opinion instead of mainstream, but I have zero formal education on the topic since grade school 67 years ago. Neil

Ara Pacis
2013-Apr-30, 07:57 PM
So Mars is about the same age as Earth. If life in the form of bacteria developed on Mars in the past, then why would it just stop at bacterial levels?

Whilst the causes of the Earth's so-called 'Cambrian Explosion' have never been shown to be clear-cut, theories covering the emergence of species complexity turn out to be an inseparable mixture of ecological, environmental, developmental (evolutionary genetics) and complexity thresholding. I would have thought Mars would not be excluded from any of these so-called 'universal' phenomena? If not, then why would we prefer searches for bacteria? After all, I thought 'once life gets started', its evolution is inevitable as far as Astrobiology is concerned?

This' bacteria boundary' seems to be more like a mental block than any logical consequence of any current evidenced-based theories.

Why is Mars being treated as a pariah planet by our faithful and intrepid exo-life hunters?

On the contrary, the theories seem to be based on the only evidence for the conditions useful for life that we have. If those theories suggest that the particulars of the planet of Mars made it stop being conducive to life in general or in relation to a certain level of complexity at a certain location on the planet, then what's the problem?

ASTRO BOY
2013-Apr-30, 07:57 PM
So Mars is about the same age as Earth. If life in the form of bacteria developed on Mars in the past, then why would it just stop at bacterial levels?

Whilst the causes of the Earth's so-called 'Cambrian Explosion' have never been shown to be clear-cut, theories covering the emergence of species complexity turn out to be an inseparable mixture of ecological, environmental, developmental (evolutionary genetics) and complexity thresholding. I would have thought Mars would not be excluded from any of these so-called 'universal' phenomena? If not, then why would we prefer searches for bacteria? After all, I thought 'once life gets started', its evolution is inevitable as far as Astrobiology is concerned?

This' bacteria boundary' seems to be more like a mental block than any logical consequence of any current evidenced-based theories.

Why is Mars being treated as a pariah planet by our faithful and intrepid exo-life hunters?


Probably simply because Mars never maintained Earth like conditions long enough for anything more complex then bacterial life to arise....
I envisage the inevitability of further evolution to depend on those conditions.

ASTRO BOY
2013-Apr-30, 08:02 PM
This' bacteria boundary' seems to be more like a mental block than any logical consequence of any current evidenced-based theories.

Why is Mars being treated as a pariah planet by our faithful and intrepid exo-life hunters?


It's not nor ever has been.
Astrobiologists and cosmologists procede on current observational evidence based on evidence of conditions on individual planets..

Selfsim
2013-May-01, 12:20 AM
On the contrary, the theories seem to be based on the only evidence for the conditions useful for life that we have. If those theories suggest that the particulars of the planet of Mars made it stop being conducive to life in general or in relation to a certain level of complexity at a certain location on the planet, then what's the problem?Now let me get this straight .. the theories we rely on which anticipate the presence of sub-surface bacterial life on Mars (and lead towards microscopes being sent), also somewhat inconveniently, predict the ultimate evolution of predators*. However, because there's no present macroscopic evidence of the ubiquitous and homogenous spreading of primary producers and larger primary, secondary and tertiary consumers, (like there is on Earth), the assumptions made about Mars' past conditions by those same theories, must somehow differ from Earth's case(??)

But come what may, those same assumption categories, which also lead to the inevitability of the emergence of life on a past water abundant, goldilocks zone planet like Mars, must however, be fixed in stone, and are not permitted the same luxury of variation and sensitivities to environmental change, when it comes to the emergence phase, eh?

Well that sounds logical and consistent … (err .. not .!.)


Footnote:
* Predation imposes competitive evolutionary pressures leading to improved survivial opportunities for prey possessing physical advantages. Successive offspring of that prey and predators, ultimately develops more complex macroscopically visible characteristics over time (according to theory). Predation has been around a lot longer than the Cambrian Era, also ..
Predation (http://en.wikipedia.org/wiki/Predator#Evolution_of_predation) appears to have become a major selection pressure shortly before the Cambrian period—around 550 million years ago—as evidenced by the almost simultaneous development of calcification in animals and algae and predation-avoiding burrowing. However, predators had been grazing on micro-organisms since at least 1,000 million years ago.… That was pushed to ~2 bya in a recent study (http://phys.org/news/2013-04-feast-clue-ancient-earth.html) finding on macroscopic evidence of heterotrophic microbes and fossils of their prey in Canada. (The chemical metabolism evidence goes even further back to ~3.5 bya as well). Whilst these are admittedly small critters, let's not forget the evolution of abundant larger scale species, which ultimately evolved and inhabited the Earth subsequently. Adaptation of the extant species didn't stop in spite of the build-up of toxic, 'sterilising gases' (as far as the predominant species of that era is concerned .. Ie: O2's effect on cyanobacteria). So why assume similar causes (eg: UV irradiation, etc) prevented evolution towards larger 'more complex' species in Mars' instance?

(As an aside, the large 'bulls-eye' structure left behind by these 'Gunflintia' creatures should also 'likely' be present on Mars (as their signatures of existence). 'We don't need no microscopes' to see that on Mars! .. So where are these supposed to be hiding? :) )

Why is the evidence of the absence of larger 'more complex' species so readily overlooked, in preference for the adoption of the belief that scant, underground microscopic bacteria 'must' still exist on Mars?

Where's the consistency?

Ara Pacis
2013-May-01, 05:39 AM
Now let me get this straight .. the theories we rely on which anticipate the presence of sub-surface bacterial life on Mars (and lead towards microscopes being sent), also somewhat inconveniently, predict the ultimate evolution of predators*. However, because there's no present macroscopic evidence of the ubiquitous and homogenous spreading of primary producers and larger primary, secondary and tertiary consumers, (like there is on Earth), the assumptions made about Mars' past conditions by those same theories, must somehow differ from Earth's case(??) I know it might sound like circular reasoning but for one fact: Mars is demonstrably different from Earth. Theories that predict one set of occurrences on Earth might either not apply, or might apply but have different results.


But come what may, those same assumption categories, which also lead to the inevitability of the emergence of life on a past water abundant, goldilocks zone planet like Mars, must however, be fixed in stone, and are not permitted the same luxury of variation and sensitivities to environmental change, when it comes to the emergence phase, eh?

Well that sounds logical and consistent … (err .. not .!.)There's a distinction to be made between applying the same theory to a different variable and getting variable results, and varying the theory to get the same results. If we had evidence that the results were the same, we might work backwards to find an explanation for why the theory was wrong. However, contradictory evidence suggesting that the theory is wrong with regard to Mars does not currently exist (as far as I am aware).

Colin Robinson
2013-May-01, 09:15 AM
After all, I thought 'once life gets started', its evolution is inevitable as far as Astrobiology is concerned?

Do astrobiologists say evolution is sure to produce similar results in different environments? Which astrobiologists say that?


Why is the evidence of the absence of larger 'more complex' species so readily overlooked,

Perhaps because once it was understood what the Martian atmosphere is like (how thin, and how low in free oxygen), scientists didn't expect large complex organisms. So "evidence" of their "absence" came as no surprise.


in preference for the adoption of the belief that scant, underground microscopic bacteria 'must' still exist on Mars?

Do astrobiologists say Martian microbes "must" exist? Or do they say Martian microbes may exist, and it would be scientifically valuable to develop ways to find out?

ASTRO BOY
2013-May-01, 09:10 PM
Do astrobiologists say evolution is sure to produce similar results in different environments? Which astrobiologists say that?



Perhaps because once it was understood what the Martian atmosphere is like (how thin, and how low in free oxygen), scientists didn't expect large complex organisms. So "evidence" of their "absence" came as no surprise.



Do astrobiologists say Martian microbes "must" exist? Or do they say Martian microbes may exist, and it would be scientifically valuable to develop ways to find out?


Logical approach, logical questions with logical answers....

Selfsim
2013-May-01, 11:16 PM
After all, I thought 'once life gets started', its evolution is inevitable as far as Astrobiology is concerned?Do astrobiologists say evolution is sure to produce similar results in different environments? Which astrobiologists say that?No .. and I personally wouldn't apply a generalisation as all encompassing as that. (Its not what said above).
Certain basic, high level features of 'Evolution' are intrinsic to NASA Astrobiology's definition of 'life', for example.

(I can't be sure of course, but I might also be tempted to bet that folk here such as 'Paul Wally', (for eg), and 'TooMany', would also likely embrace the concept of universality of Evolution wherever life emerges .. based on past conversations, that is).

From the NASA Astrobiology Roadmap:

As a consequence of geological, climatologic, and microbial processes acting across geological time scales, the physical-chemical environments on Earth have been changing, thereby determining the path of evolution of subsequent life. For example, the release of molecular oxygen by cyanobacteria as a by-product of photosynthesis as well as the colonization of Earth’s surface by metazoan life contributed to fundamental, global environmental changes. The altered environments, in turn, posed novel evolutionary opportunities to the organisms present, which ultimately led to the formation of our planet’s major animal and plant species. Therefore, this “co-evolution” between organisms and their environment is an intrinsic feature of living systems.Thus, Evolution is inevitable .. it is 'intrinsic' to how living systems develop over geological timespans.


Perhaps because once it was understood what the Martian atmosphere is like (how thin, and how low in free oxygen), scientists didn't expect large complex organisms. So "evidence" of their "absence" came as no surprise.According to the Mars Ocean hypothesis, early Mars would have had a thicker atmosphere to allow liquid water on the surface and would have been fairly similar to Earth's. Given that large complex organisms developed comparatively rapidly here on Earth, there seems to have been opportunities for the same to have have happened on Mars, given an extant microbe population, (and given present theory on Mars' geological history .. which is now based on on-site geological evidence gathered by the rovers).


Do astrobiologists say Martian microbes "must" exist?My comment was in keeping with the fundamental quest for detection of Martian microbial life, which is the general subject of this thread.

Some here, (and perhaps Levin), seem to be unswervably convinced that microbial life on Mars exists .. and in his case, has perhaps already been detected. The synergy between Earthly test results and Martian Viking results, appears to now being used as 'evidence' in support of the conviction that it exists there.

Or do they say Martian microbes may exist, and it would be scientifically valuable to develop ways to find out?Surely we already know of the ways to find out! We have heaps of microbes here to test the detection of them! (Hence the 'vegie-garden dirt' line).

Selfsim
2013-May-01, 11:23 PM
Logical approach, logical questions with logical answers...... with accompanying and many 'inconvenient' consequences noticeably missing from the argument.

Eg: Those which would purport to answer to questions such as:
"Why is there no macro evidence of higher life-forms .. which, (as per Evolution), are a logical consequence of microbial populations?"

If Astrobiology draws upon Earth's mainstream biological theories, then what is the justification for overlooking the comprehensive view in its entirety, of the variously invoked theories (like Evolution)?

Is this 'cherry-picking' by a stream of supposedly 'mainstream science'?

Colin Robinson
2013-May-02, 09:44 AM
Thus, Evolution is inevitable .. it is 'intrinsic' to how living systems develop over geological timespans.

Evolution may indeed be intrinsic in the sense that living things anywhere undergo random mutation and natural selection; and they both adapt to their environments and change their environments. But why would that mean similar outcomes on different planets, especially planets with different geological histories?


According to the Mars Ocean hypothesis, early Mars would have had a thicker atmosphere to allow liquid water on the surface and would have been fairly similar to Earth's. Given that large complex organisms developed comparatively rapidly here on Earth,

The Earth is 4.6 billion years old. It has had multicellular life for about 1 billion years. You call that comparatively rapid?


there seems to have been opportunities for the same to have have happened on Mars, given an extant microbe population, (and given present theory on Mars' geological history .. which is now based on on-site geological evidence gathered by the rovers).

Except that the Mars ocean hypothesis is about Mars some 3.8 billion years ago...

Selfsim
2013-May-02, 11:02 AM
Evolution may indeed be intrinsic in the sense that living things anywhere undergo random mutation and natural selection; and they both adapt to their environments and change their environments. But why would that mean similar outcomes on different planets, especially planets with different geological histories?

The Earth is 4.6 billion years old. It has had multicellular life for about 1 billion years. You call that comparatively rapid?Not all changes are solely due to externally imposed environmental conditions.
Anyway, it depends (again) on how 'similar outcomes' is defined. What I've said in this conversation, requires accepting that the transition to multicellularity is a relatively easy step in evolutionary terms. It happened in at least 25 different species groups in Earth's past, it has been recreated in the lab, and from Earth's fossil record, it appears to have occurred inside a period of less than about 500 million years.

Absence of visible macro-scale multicellular lifeforms on Mars, (or their remnants in a previous life-favoring habit), is a data point worthy of deliberation and requires some kind of explanation. Where is it? What is it?


Except that the Mars ocean hypothesis is about Mars some 3.8 billion years ago... .. and so?

ASTRO BOY
2013-May-02, 08:59 PM
Thus, Evolution is inevitable .. it is 'intrinsic' to how living systems develop over geological timespans.




Evolution is inevitable and intrinsic as long as cosmological circumstances as well as local environmental issues allow.
You seem to be missing certain relevant points.
Mars underwent great changes....you know that.
All evidence so far suggests that the planet was once apparently far more habitable than it is at this time.
But if bacterial/microbrial life did/does exist on the planet, the early changes with regards to its magnetosphere and atmosphere would have most likely inhibited the inevitability of evolution no matter how intrinsic.

ASTRO BOY
2013-May-02, 09:08 PM
Absence of visible macro-scale multicellular lifeforms on Mars, (or their remnants in a previous life-favoring habit), is a data point worthy of deliberation and requires some kind of explanation. Where is it? What is it?

.. and so?


Rapid environmental atmospheric and geological changes shortly after the advent of microbrial/bacterial life and all that it would entail.

FarmMarsNow
2013-May-02, 09:43 PM
Don't laugh, but is there any chance that Earth bacteria or Earth life may have somehow infected Mars millions or billions of years ago? For instance if a very large asteroid smashed into Earth, could it have dispersed some bacteria or other life into space, been picked up by or blown to Mars?

Selfsim
2013-May-02, 09:54 PM
Earth underwent rapid environmental and atmospheric changes in the past, including one which wiped out almost all extant anaerobic species of the time. And at least there's geophysical and fossil record evidence of that. Yet, multicellularity, larger and predatorial species was 'no problem' from thereon, in spite of such upheavals.

The planetary gas escape rates from both Mars and Earth are somewhat controversial. (There is evidence for both having about the same rates at present and other evidence suggesting that solar events cause more rapid erosion of Mars'). The upcoming MAVEN mission might produce more hard data on that front. The comparison pathway, (Earth vs Mars), has too many gaps to form a solid basis for solid theory development.

At the moment, the 'planetary upheaval' story in Mars' instance is just that .. a story. Until some evidence is found of ancient extant microbial martians, it is a redundant story and certainly not mainstream evidenced-based science. The mainstream answer to my query is 'unknown'. If Levin is right about Viking's results, then as Curiosity has found a once life-habitable environment at Gale crater, fossil evidence of ancient microbial activity should be present there, if life ever emerged on Mars. It is more than capable of detecting it, too. If it finds none, then 'The Story' is unsupported by the evidence it requires .. ie: evidence of extant ancient life which was co-incident with warmness and wetness. It requires this in order for it to gain any credibility legs.

Selfsim
2013-May-02, 09:59 PM
Don't laugh, but is there any chance that Earth bacteria or Earth life may have somehow infected Mars millions or billions of years ago? For instance if a very large asteroid smashed into Earth, could it have dispersed some bacteria or other life into space, been picked up by or blown to Mars?The 'chance' you mention is entirely dependent on finding evidence of past life on Mars in the first place. Without that evidence, the answer to your question is moot.

Colin Robinson
2013-May-02, 10:12 PM
Not all changes are solely due to externally imposed environmental conditions.

Who said they were?


Anyway, it depends (again) on how 'similar outcomes' is defined. What I've said in this conversation, requires accepting that the transition to multicellularity is a relatively easy step in evolutionary terms. It happened in at least 25 different species groups in Earth's past, it has been recreated in the lab, and from Earth's fossil record, it appears to have occurred inside a period of less than about 500 million years.

When and how was the transition to multicellularity "recreated in the lab"?

In any case, that transition happened in nature around 3 billion years after life on Earth got started. Whether or not it was a easy step when it happened, it was a comparatively late step in the overall history of evolution.

Emergence of the first, microscopic eucaryotes was a highly significant step in evolution that came about a billion years earlier than multicellular life, but around 2 billion years after the first living cells.



Except that the Mars ocean hypothesis is about Mars some 3.8 billion years ago...

.. and so?

So, it was long before multicellular life appeared here on Earth. If evolution on early Mars was running parallel with evolution on early Earth, as your argument supposes, then there would not have been time for multicellular forms to develop.

Colin Robinson
2013-May-02, 11:13 PM
Don't laugh, but is there any chance that Earth bacteria or Earth life may have somehow infected Mars millions or billions of years ago? For instance if a very large asteroid smashed into Earth, could it have dispersed some bacteria or other life into space, been picked up by or blown to Mars?

Yes, some scientific modeling has been done which suggests there is a chance of this sort of thing happening.

An earlier thread on this topic, which gives titles of some relevant books and articles.

Protozoan panspermia (http://cosmoquest.org/forum/showthread.php?121551-Protozoan-panspermia)

Selfsim
2013-May-02, 11:53 PM
Who said they were?I did.

The point being, that the outcomes of evolving martian life, doesn't have to fit into Earth's evolutionary timeframes. In a generalised model, the relationships between external environmental factors are only one part of a very complex (and largely incomplete) 'equation'. The initial starting conditions are another .. as are a myriad of other factors. Certain macro model life features, (according to the hypotheses being pursued), are actually part of the definition applied to 'life'. These would persist in spite of some environmental changes, and terminate because of others. There is no certainty in arguing from a purely crudely known, crudely resolved geophysical Earth-centric theory, about the changes in detailed features which could (in theory) could 'tip' in any direction.

As it turns out, multicellularity does have lab evidence supporting its sensitivities to external environmental changes. This much is known .. and it can easily happen quickly .. and it has to follow unicellularity. In this case, the key generalised function creating the pressure to evolve to multicellularity is co-operation in a resource competitive, gravity based environment, which is pretty much a fundamental feature in any evolving 'life' colony (by definition and in evidence).


When and how was the transition to multicellularity "recreated in the lab"?Ratcliff et al, announced PNAS January 2012. (http://www.pnas.org/content/early/2012/01/10/1115323109.full.pdf)
Quick snapshot article here. (http://www.wired.com/wiredscience/2012/01/evolution-of-multicellularity/)


In any case, that transition happened in nature around 3 billion years after life on Earth got started. Whether or not it was a easy step when it happened, it was a comparatively late step in the overall history of evolution.The life 'transition' steps usually lack the fine precision needed, (in this case), for comparative purposes (Earth vs Mars). I find this to be another reason for interpreting most of what we hear about to be a fairly rubbery 'story' (which is as good as anything as far as research pursuit is concerned, mind you .. and that's not my point here).
The lab evidence paints a finer degree of detail, temporal resolution, environmental sensitivities, and hence affords a better theoretical explanation than a purely, largely incomplete crude, low resolution, fossil/geophysical evidence record.


Emergence of the first, microscopic eucaryotes was a highly significant step in evolution that came about a billion years earlier than multicellular life, but around 2 billion years after the first living cells.
...
So, it was long before multicellular life appeared here on Earth. If evolution on early Mars was running parallel with evolution on early Earth, as your argument supposes, then there would not have been time for multicellular forms to develop.From the linked article ..

An evolutionary transition that took several billion years to occur in nature has happened in a laboratory, and it needed just 60 days.Then from the paper's co-author …

The new study suggests that environmental conditions are paramount: Give single-celled organisms reason to go multicellular, and they will.Then from the paper itself ...

Although known transitions to complex multicellularity, with clearly differentiated cell types, occurred over millions of years (9, 33), we have shown that the first crucial steps in the transition from unicellularity to multicellularity can evolve remarkably quickly under appropriate selective conditions.A rapid martian multicellularity development phase would have left adequate time for macro scale fossil evidence, (provided unicellularity happened in the first place).

I see no reasons for discarding this 'possibility' .. do you?

Also .. if martian microbes are thought to exist underground today, then they should be accompanied by multicellular (complex, larger), lifeforms which leave evidence brought to the surface by impactors, volcanoes etc.
Microbes and macro fossils go hand-in-hand. Where one exists, one expects to find the other.

ASTRO BOY
2013-May-03, 01:25 AM
A rapid martian multicellularity development phase would have left adequate time for macro scale fossil evidence, (provided unicellularity happened in the first place).

I see no reasons for discarding this 'possibility' .. do you?

Also .. if martian microbes are thought to exist underground today, then they should be accompanied by multicellular (complex, larger), lifeforms which leave evidence brought to the surface by impactors, volcanoes etc.
Microbes and macro fossils go hand-in-hand. Where one exists, one expects to find the other.


So the conclusions you draw from your assumptions are that single cell life does not exist nor has it ever existed on Mars?
......I don't believe we know enough about Mars, It's early atmospheric content, the salinity or otherwise of any liquid water and its early tetonic geography and the time frame of each to reach any firm conclusion.


I do believe [as apparently do many in the related discipline] that simple cell life may have existed in the past and maybe still do based on the evidence that far better conditions did exist in the past, long enough to support such simple life, but unfavourable for anything more complex apparently.

Colin Robinson
2013-May-03, 02:29 AM
As it turns out, multicellularity does have lab evidence supporting its sensitivities to external environmental changes. This much is known .. and it can easily happen quickly .. and it has to follow unicellularity. In this case, the key generalised function creating the pressure to evolve to multicellularity is co-operation in a resource competitive, gravity based environment, which is pretty much a fundamental feature in any evolving 'life' colony (by definition and in evidence).

Ratcliff et al, announced PNAS January 2012. (http://www.pnas.org/content/early/2012/01/10/1115323109.full.pdf)
Quick snapshot article here. (http://www.wired.com/wiredscience/2012/01/evolution-of-multicellularity/)

Thank you for these references, Selfsim.

The organism used in the experiment is a species of yeast. For a bit of background, let's look at what Wikipedia says about yeasts in general.


Yeasts are unicellular, although some species with yeast forms may become multicellular through the formation of a string of connected budding cells known as pseudohyphae, or false hyphae, as seen in most molds.

Ratcliff's paper in fact mentions (on page 2) that one of the yeast species which can form pseudo-hyphae is the very species used in the experiment, Saccharomyces cerevisiae. The paper explains how the snowflake clusters produced in the experiment differ from pseudo-hyphae.

So, Ratcliff et al have not brought about evolution from a strictly unicellular species to a multicellular one. Rather, they have taken a species that is usually unicellular, but is also known to form comparatively simple multicellular structures (the pseudo-hyphae), and they have induced that species to form a different sort of multicellular structure (the snowflake cluster).

It's a very interesting result.

But does it prove that any planet with unicellular life is certain to have multicellular species as well?

I don't think so.

Selfsim
2013-May-03, 02:31 AM
So the conclusions you draw from your assumptions are that single cell life does not exist nor has it ever existed on Mars?No.
There is no need for any conclusion.

......I don't believe we know enough about Mars, It's early atmospheric content, the salinity or otherwise of any liquid water and its early tetonic geography and the time frame of each to reach any firm conclusion.Agreed.
.. Therefore talk of microbes and sending test equipment specifically designed for that 'possibility' is premature, as there are other equally valid interpretations, (some even supported by lab based empirical evidence).

This was all learned decades ago .. from Viking's misguided ambiguous LR tests and yet some still cling to the belief that microbial life exists (and was detected) there.

Fascinating!


I do believe [as apparently do many in the related discipline] that simple cell life may have existed in the past and maybe still do based on the evidence that far better conditions did exist in the past, long enough to support such simple life, but unfavourable for anything more complex apparently.A belief!
.. (And not the mainstream science position).

Selfsim
2013-May-03, 02:56 AM
But does it prove that any planet with unicellular life is certain to have multicellular species as well?Proof only happens with direct evidence .. and in this case, we presently have an absence of evidence, (unless one is a 'Levinist'), and a lab demonstrated 'contingent predication' (from theory).

What we are discussing is the implications on speculation, of the key principles of Earthly theories (which guide us). Those theories cannot be taken as 'proof' of anything, nor do their 'predictions' constitute anything 'mainstream'.

Don J
2013-May-03, 03:08 AM
No.
.. Therefore talk talk of microbes and sending test equipment specifically designed for that 'possibility' is premature, as there are other equally valid interpretations, (some even supported by lab based empirical evidence).


Do you have any links about those empirical evidence tested in laboratory which produce the same results detected by the LR on Mars?


This was all learned decades ago .. from Viking's misguided ambiguous LR tests and yet some still cling to the belief that microbial life exists (and was detected) there.

Fascinating!

The reason for the ambiguity was caused by an another instrument which was uncorrectly calibrated. The instrument is called the GCMS and was conceived by another team of scientists.

The sensitivity of the GCMS instrument was eight order of magnitude lower than the LR.... The GCMS even frequently obtained negative results with live soils on Earth.
See page 5 and 6 of the PDF paper
http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf

To resume, the sensitivity of GCMS on Viking was set to detect organic content "in the kinds of soils you might have in your backyard or in arable land."but totally unable to detect organic content "in samples taken from Antarctica and from Siberia with active life that had the organic content of a few million cells per gram."

Don J
2013-May-03, 04:28 AM
Proof only happens with direct evidence .. and in this case, we presently have an absence of evidence, (unless one is a 'Levinist'), and a lab demonstrated 'contingent predication' (from theory).

What we are discussing is the implications on speculation, of the key principles of Earthly theories (which guide us). Those theories cannot be taken as 'proof' of anything, nor do their 'predictions' constitute anything 'mainstream'.
The Likelihood of Methane-producing Microbes on Mars....
............
European Space agency article
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Water_and_methane_maps_overlap_on_Mars_a_new_clue2


ESA PR 51-2004. Recent analyses of ESA’s Mars Express data reveal that concentrations of water vapour and methane in the atmosphere of Mars significantly overlap.

This result, from data obtained by the Planetary Fourier Spectrometer (PFS), gives a boost to understanding of geological and atmospheric processes on Mars, and provides important new hints to evaluate the hypothesis of present life on the Red Planet.

Levin's about that discovery:
http://www.gillevin.com/Mars/SPIE_Miller__CH4_2010.pdf

Selfsim
2013-May-03, 09:07 AM
Don J;

Feel free to continue campaigning for a second attempt at life detection. (Same for Levin).

I personally feel very little motivation for repeating experiments which have already returned inconclusive results (regardless of the reasons and explanations for that).

The strategy which motivated the experiments in the first place was fundamentally flawed, (and still persists), so I feel great reticence when it comes to supporting a repeat mission. The idea of detecting something to 'prove' someone's speculative fantasy, seems akin to the hunt for the Holy Grail.

If life turns up whilst exploring the planet, then so much the better.
If it exists there, I feel pretty confident it'll be noticed.

Colin Robinson
2013-May-03, 09:46 AM
If life turns up whilst exploring the planet, then so much the better.
If it exists there, I feel pretty confident it'll be noticed.

Not surprised you feel confident. After all, you wrote in your earlier posting...


Microbes and macro fossils go hand-in-hand. Where one exists, one expects to find the other.

In which case we can work out whether microbes are about without using a mass spectrometer, or a microscope, or even a magnifying glass.

It's just a matter of checking the sky-line for brontosaurus bones sticking out of the sand.

ASTRO BOY
2013-May-03, 11:06 AM
.. Therefore talk of microbes and sending test equipment specifically designed for that 'possibility' is premature, as there are other equally valid interpretations, (some even supported by lab based empirical evidence).


The only way to get an answer to the possibility of life to ever have existed is to send test equipment. That will then give us some extra validity one way or the other and possibily support or invalidate other interpretations.
Sitting on ones hands achieves nothing.





This was all learned decades ago .. from Viking's misguided ambiguous LR tests and yet some still cling to the belief that microbial life exists (and was detected) there.


Viking's reported findings were an interpretation which underwent peer review, plus even if that result was conclusive in the negative, certainly does not mean that microbrial life could not have, or had not existed somewhere on Mars sometime.......



.. (And not the mainstream science position).
I don't believe we have a firm mainstream position on whether life did or did not exist at one time on Mars.
The question is still undecided with plenty standing with the affirmative position.
The evidence for past milder conditions on Mars, is also evidence also for the possible likelyhood of microbrial life.

Don J
2013-May-04, 03:28 AM
Don J;

Feel free to continue campaigning for a second attempt at life detection. (Same for Levin).

A second attempt at life detection on Mars is inevitable which will give positive results(again) and that will lead to a big dilemma about a collect and return sample mission. The debate will turn around the danger of contamination....then as a perfect timing it will be decided to send a human mission to Mars.


I personally feel very little motivation for repeating experiments which have already returned inconclusive results (regardless of the reasons and explanations for that).

Datas collected by other probes after Viking missions rather point to Levin's conclusion, for example the detection of methane in the Martian atmosphere.
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Water_and_methane_maps_overlap_on_Mars_a_new_clue2


The measurements confirm so far that the amount of methane is very small – about 10 parts in a thousand million, so its production process is probably small. However, the exciting question remains: “Where does this methane come from?”

Methane, unless it is continuously produced by a source, only survives in the Martian atmosphere for a few hundreds of years because it quickly oxidises to form water and carbon dioxide, both present in the Martian atmosphere. So, there must be a mechanism that refills the atmosphere with methane.
Based on our experience on Earth, the methane production could be linked to volcanic or hydro-thermal activity on Mars. The High Resolution Stereo camera (HRSC) on Mars Express could help us identify visible activity, if it exists, on the surface of the planet”, continues Formisano. Clearly, if it was the case, this would imply a very important consequence, as present volcanic activity had never been detected so far on Mars.

Other hypotheses could also be considered. On Earth, methane is a by-product of biological activity, such as fermentation. “If we have to exclude the volcanic hypothesis, we could still consider the possibility of life,” concludes Formisano.

PFS observed that, at 10-15 kilometres above the surface, water vapour is well mixed and uniform in the atmosphere. However, it found that, close to the surface, water vapour is more concentrated in three broad equatorial regions: Arabia Terra, Elysium Planum and Arcadia-Memnonia.

Here, the concentration is two to three times higher than in other regions observed. These areas of water vapour concentration also correspond to the areas where NASA’s Odyssey spacecraft has observed a water ice layer a few tens of centimetres below the surface, as Dr Vittorio Formisano, PFS principal investigator, reports.

New in-depth analysis of PFS data also confirms that methane is not uniform in the atmosphere, but concentrated in some areas. The PFS team observed that the areas of highest concentration of methane overlap with the areas where water vapour and underground water ice are also concentrated. This spatial correlation between water vapour and methane seems to point to a common underground source.








The strategy which motivated the experiments in the first place was fundamentally flawed, (and still persists), so I feel great reticence when it comes to supporting a repeat mission. The idea of detecting something to 'prove' someone's speculative fantasy, seems akin to the hunt for the Holy Grail.

I don't think that a new mission at life detection on Mars will be guided by fantasy but rather by studying all the datas gathered by all the missions on Mars including Viking life detection results.

Selfsim
2013-May-04, 07:47 AM
A second attempt at life detection on Mars is inevitable which will give positive results(again) and that will lead to a big dilemma about a collect and return sample mission. The debate will turn around the danger of contamination....then as a perfect timing it will be decided to send a human mission to Mars.All outlined in the notorious NASA Astrobiology Roadmap. Nothing new here .. its just a plan with only inconclusive data and more stories behind it all.


Datas collected by other probes after Viking missions rather point to Levin's conclusion, for example the detection of methane in the Martian atmosphere.
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Water_and_methane_maps_overlap_on_Mars_a_new_clue2
Old hat ... the 2004 Mars Express PFS lacks precision, and requires an interpretive model which does not explain all the spectral anomalies in the data. The other two Earth-based measurements had difficulties distinguishing Mars' methane absorption spectra from Earth's. Curiosity has found none so far (why not?).
Again, inconclusive (at best).


I don't think that a new mission at life detection on Mars will be guided by fantasy but rather by studying all the datas gathered by all the missions on Mars including Viking life detection results.I don't think there's sufficient data guiding anything. NASA is simply following the Roadmap .. drawn up by fanciful 'Astrobiologists' .. (queue: Colin).

Selfsim
2013-May-04, 08:17 AM
The only way to get an answer to the possibility of life to ever have existed is to send test equipment. That will then give us some extra validity one way or the other and possibily support or invalidate other interpretations.
Sitting on ones hands achieves nothing.See, the problem lies in the first part of the first statement: "The only way to get an answer to the possibility of life to ever have existed ..."
The very wording implies that the search for life is the primary objective. That's what Viking was all about .. and look what we ended up with .. inconclusive results (which no-one can agree on), a bunch of 'faithful' 'hopefuls' unwilling to acknowledge the inconclusive outcomes, and the lead bio-testing design engineer attempting to resurrect his reputation by publishing seemingly endless sequels.

'Test equipment' requires designs. Designs call for models of what it is that is to be tested. Models come from speculation which assume that what the test equipment is designed for, exists, (for it to demonstrate its capabilities). The whole shebang is hopelessly flawed I'm afraid, and speculative 'Astrobiology' just confuses things even more.

Exploration of visible macro-features atypical for the landscape (along with geological test gear) is sufficient to eliminate what the sample isn't. From thereon, design of equipment to test the sample, is entirely dependent on optical (macro) examination, and the chemical composition of the sample. Trying to 'test for life' in advance of knowing the nature of the sample is just about pointless .. particularly when there is no sample!


Viking's reported findings were an interpretation which underwent peer review, plus even if that result was conclusive in the negative, certainly does not mean that microbrial life could not have, or had not existed somewhere on Mars sometime.......The result wasn't 'conclusive in the negative' ... it was inconclusive (in the positive)!


I don't believe we have a firm mainstream position on whether life did or did not exist at one time on Mars.
The question is still undecided with plenty standing with the affirmative position.
The evidence for past milder conditions on Mars, is also evidence also for the possible likelyhood of microbrial life.As I said: 'unknown'.

ASTRO BOY
2013-May-04, 08:52 AM
See, the problem lies in the first part of the first statement: "The only way to get an answer to the possibility of life to ever have existed ..."
The very wording implies that the search for life is the primary objective. That's what Viking was all about .. and look what we ended up with .. inconclusive results (which no-one can agree on), a bunch of 'faithful' 'hopefuls' unwilling to acknowledge the inconclusive outcomes, and the lead bio-testing design engineer attempting to resurrect his reputation by publishing seemingly endless sequels.



I for one would rather put the prospect for progress and discovery with the decisions of a "bunch of faithful hopefuls", then with the non decisions and negative actions on those that would do nothing and stagnate.
And of course as long as the results remain "inconclusive" NASA and other orginisations will continue to search for more validity or otherwise to those inconclusive results on our behalf.......I certainly will continue to support them in that endeavour in whatever way I can.

TooMany
2013-May-04, 07:22 PM
The very wording implies that the search for life is the primary objective. That's what Viking was all about .. and look what we ended up with .. inconclusive results (which no-one can agree on), a bunch of 'faithful' 'hopefuls' unwilling to acknowledge the inconclusive outcomes, and the lead bio-testing design engineer attempting to resurrect his reputation by publishing seemingly endless sequels.

'Test equipment' requires designs. Designs call for models of what it is that is to be tested. Models come from speculation which assume that what the test equipment is designed for, exists, (for it to demonstrate its capabilities). The whole shebang is hopelessly flawed I'm afraid, and speculative 'Astrobiology' just confuses things even more.

Exploration of visible macro-features atypical for the landscape (along with geological test gear) is sufficient to eliminate what the sample isn't. From thereon, design of equipment to test the sample, is entirely dependent on optical (macro) examination, and the chemical composition of the sample. Trying to 'test for life' in advance of knowing the nature of the sample is just about pointless .. particularly when there is no sample!

The result wasn't 'conclusive in the negative' ... it was inconclusive (in the positive)!

As I said: 'unknown'.

And your point is what? Astrobiologists are idiots because 1) life cannot possibly exist elsewhere? 2) if it does, it will be so different that our silly instruments will not detect it? 3) Viking failed to conclusively detect life, so all efforts to conclusively verify it are futile? 3) if something is unknown it should not be pursued as though it might exist? 4) anything that is not directly known with certainty is "speculative" and therefore deserves no further research?

You hammer on this endlessly and I think completely pointlessly. Let me ask you this: what do you want people to do or think in the context of extraterrestrial life? Anything specific or do you just like trying to make fun of "speculative" scientists in order to elevate yourself above them?

ASTRO BOY
2013-May-04, 09:30 PM
And your point is what? Astrobiologists are idiots because 1) life cannot possibly exist elsewhere? 2) if it does, it will be so different that our silly instruments will not detect it? 3) Viking failed to conclusively detect life, so all efforts to conclusively verify it are futile? 3) if something is unknown it should not be pursued as though it might exist? 4) anything that is not directly known with certainty is "speculative" and therefore deserves no further research?




I don't believe we really have to worry too much about whether any or all of the above points are true within certain sectors of society.
Coupled with the two variables of politics and economics, they may tend to slow things down some, but in the end the search will continue for ET life as well as going where we have not gone before.
No amount of negativity or pessimism will halt either of those goals.
Some are even saying that positive evidence of ET life will be found within our lifetimes.
And even if that prediction fails to come to fruition, the sheer size in numbers and extent of the Universe, will see the search continue culminating with manned efforts and manned stellar exploration beyond our solar system.
That put simply is our destiny.

TooMany
2013-May-04, 09:57 PM
I don't believe we really have to worry too much about whether any or all of the above points are true within certain sectors of society.
Coupled with the two variables of politics and economics, they may tend to slow things down some, but in the end the search will continue for ET life as well as going where we have not gone before.
No amount of negativity or pessimism will halt either of those goals.
Some are even saying that positive evidence of ET life will be found within our lifetimes.
And even if that prediction fails to come to fruition, the sheer size in numbers and extent of the Universe, will see the search continue culminating with manned efforts and manned stellar exploration beyond our solar system.
That put simply is our destiny.

Indeed I agree with you. Optimists will make the advances and there are always the naysayers in any endeavor. I was just curious about the motivation. It is a common stance, not unique to Selfsim.

ASTRO BOY
2013-May-04, 11:28 PM
I was just curious about the motivation. It is a common stance, not unique to Selfsim.


Yes, even in spite of what history has shown throughout the ages.

Selfsim
2013-May-05, 07:33 AM
0) And your point is what? Astrobiologists are idiots because 1) life cannot possibly exist elsewhere? 2) if it does, it will be so different that our silly instruments will not detect it? 3) Viking failed to conclusively detect life, so all efforts to conclusively verify it are futile? 4) if something is unknown it should not be pursued as though it might exist? 5) anything that is not directly known with certainty is "speculative" and therefore deserves no further research?(My numbering changes in bold .. to add precision and clarity to your query).

(0) I have never used the term "idiot", and I do not think of others in this way;
(1) Unknown (and largely irrelevant);
(2) Unknown;
(3) Viking's tests were designed from a flawed principle, (which others here, seem keen to repeat). They allowed for the possibility of a non-result, due to a lack of prior necessary and sufficient data, needed to isolate the samples from their native environment. This allowed for inconclusivity in associating the results with the samples.
(4) Thinking something as complex as life might exist elsewhere, but having no data on the possible configurations in which it might present itself, (from a simply astronomical-in-scale possible permutation space), results in no impact on its existence, or otherwise. Noticing things which present as atypical in an alien environment, is an effective detection strategy. (It is the current exploration strategy anyway ... regardless of this conversation);
(5) Anything not directly known, is unknown. It doesn't simply exist because speculation says it does. Research commences from the observation of something, followed by its isolation from its surroundings. Looking for a ghost, doesn't result in the discovery of a ghost, simply because I once convinced myself that ghosts might exist!


Let me ask you this: what do you want people to do or think in the context of extraterrestrial life?People can do and think whatever they like. I am no exception. I encourage people to think in a more disciplined and more productive way .. as opposed to being motivated from the initial, predestined principle of: "I think .. therefore it is"


Anything specific or do you just like trying to make fun of "speculative" scientists in order to elevate yourself above them?I'd say that comment is the beginnings of an ad-hom attack, and so I choose not to give it a serious response. Care to try again?

ASTRO BOY
2013-May-05, 08:48 AM
(5) Anything not directly known, is unknown. It doesn't simply exist because speculation says it does. Research commences from the observation of something, followed by its isolation from its surroundings. Looking for a ghost, doesn't result in the discovery of a ghost, simply because I once convinced myself that ghosts might exist!

People can do and think whatever they like. I am no exception. I encourage people to think in a more disciplined and more productive way .. as opposed to being motivated from the initial, predestined principle of: "I think .. therefore it is"



And yet science and cosmology procede on assumptions that are literally taken as truth or known...Why???...Becuase in many cases even though something may not be directly known, the data available makes its existence overwhelmingly positive.........Overwhelmingly enough to realise that although there is a non zero chance the answer maybe not what is expected, it's a reasonably safe bet and it's reasonably safe to procede under the assumption that the existence is positive.
And that to put it simply is why we will still search for bacterial life on Mars now, and life elswhere in the solar system on many promising environments....Imagine, Speculate, search and research.....That's science, ask Albert Einstein.

FarmMarsNow
2013-May-05, 05:29 PM
The necessity of compromise assures that a microscope is going to be sent to Mars. If one isn't sent, then there won't be as much support for missions. May as well start drawing it up. Those who believe in the possibility of life search for it, and those who don't search to implant it. Those who are interested in exploration are a mixed group of both types.

Don J
2013-May-05, 08:21 PM
(3) Viking's tests were designed from a flawed principle,....

Dare to explain more about what you mean about "flawed principle"?


They allowed for the possibility of a non-result, due to a lack of prior necessary and sufficient data, needed to isolate the samples from their native environment. This allowed for inconclusivity in associating the results with the samples.

No,that is the insensibility of the GCMS (organic matter detection instrument) destined to find organic matter in the samples which caused the ambiguity about the LR results ... this is explained by Levin in the PDF page 5-6 ...the GCMS instrument which was conceived by another team, was set to detect organic content in the kinds of soils you might have in your backyard or in arable land,but totally unable to detect organic content in samples taken from Antarctica and from Siberia with active life that had the organic content of a few million cells per gram...-as demonstrated by tests made after the Viking mission using a similar GCMS organic matter detection instrument.-
There was at least 30 attempts to find an explanation for the positive life detection results made by the LR instrument which turned around the mantra that it was chemistry rather than life. But none of these explanations were supported by peer reviewed papers.
see this post from another thread for details
http://cosmoquest.org/forum/showthread.php?12754-Levin-going-a-bit-too-far-in-his-zealotry&p=2118158#post2118158

TooMany
2013-May-05, 11:21 PM
(5) Anything not directly known, is unknown. It doesn't simply exist because speculation says it does. Research commences from the observation of something, followed by its isolation from its surroundings. Looking for a ghost, doesn't result in the discovery of a ghost, simply because I once convinced myself that ghosts might exist!

We have made many observations, particularly in the last century. We have learned much about life on earth and we understand the conditions under which it exists. We also have evidence of some similar conditions early on Mars. This makes it quite scientific to say that "life may have existed on Mars and may even still exist". This is something that we are trying to determine. It is nothing like your characterization of "looking for a ghost" which implies that the pursuit is unjustified or even absurd.



People can do and think whatever they like. I am no exception. I encourage people to think in a more disciplined and more productive way .. as opposed to being motivated from the initial, predestined principle of: "I think .. therefore it is"


In this instance you are absolutely wrong to state that this is an example of "I think ... therefore it is". So tell us, in this instance what would be productive.



I'd say that comment is the beginnings of an ad-hom attack, and so I choose not to give it a serious response. Care to try again?

You persistance in insulting researchers and all others involved in Mars exploration with the implication that they are making wild, unsupported speculations or chasing ghosts (in the field of astrobiology) has tried my patience.

Selfsim
2013-May-06, 07:42 AM
(3) Viking's tests were designed from a flawed principle, (which others here, seem keen to repeat). They allowed for the possibility of a non-result, due to a lack of prior necessary and sufficient data, needed to isolate the samples from their native environment. This allowed for inconclusivity in associating the results with the samples.Dare to explain more about what you mean about "flawed principle"?Exactly what I said above (see underlined).

The design of the GCMS should have catered for the detection of low concentration organics. Without this capability, no conclusions can be drawn.
Why was it not calibrated to detect lower levels of organics? Somewhere, someone decided on a set of assumed design parameters, which may not have been valid in the selected Martian testing environment. How/why did this occur?

The strategy issue I raise is related to the subtle difference in approach between the empirical and experimental methodologies. When exploring, the empirical method is quite effective. Experimental methodology requires prior confidence in the relationships amongst the experimental parameters. No such confidence exists at present in exo-life detection/experimentation. The Viking debacle demonstrated this quite clearly, (I thought).


No,that is the insensibility of the GCMS (organic matter detection instrument) destined to find organic matter in the samples which caused the ambiguity about the LR results ... this is explained by Levin in the PDF page 5-6 ...the GCMS instrument which was conceived by another team, was set to detect organic content in the kinds of soils you might have in your backyard or in arable land,but totally unable to detect organic content in samples taken from Antarctica and from Siberia with active life that had the organic content of a few million cells per gram...-as demonstrated by tests made after the Viking mission using a similar GCMS organic matter detection instrument.-What I said above covers where Levin is coming from.
The GCMS instrument should have been capable of detecting organics in the sample area (if present).

If it wasn't, then clearly it wasn't capable of supporting the LR results, and thus the whole life detection strategy was flawed.
Ya can't have the type of life being targetted, without having organics present ... so we can't rely solely on the LR results, without the confirmation of organics.

Taken together, the GCMS and LR results still lead to an inconclusive interpretation.

It doesn't matter now if the GCMS was 'at fault', or the LR results were. The end results remain inconclusive.


There was at least 30 attempts to find an explanation for the positive life detection results made by the LR instrument which turned around the mantra that it was chemistry rather than life. But none of these explanations were supported by peer reviewed papers.
see this post from another thread for details
http://cosmoquest.org/forum/showthread.php?12754-Levin-going-a-bit-too-far-in-his-zealotry&p=2118158#post2118158There is now more data from Phoenix and other missions .. The Levin paper was published prior to Phoenix perchlorate results, also .. so it is now somewhat dated.

Selfsim
2013-May-06, 08:24 AM
We have made many observations, particularly in the last century. We have learned much about life on earth and we understand the conditions under which it exists. We also have evidence of some similar conditions early on Mars. .. And we have established no clear causal relationships between Earth's past environment and its causal role in the emergence of life. We have no feel for the sensitivites involved. As a result, we cannot say whether the past Martian environment would cause the same 'effects' as it did here.

We do have a grasp of the sensitivities of modern life to present-day environmental conditions, however.


In this instance you are absolutely wrong to state that this is an example of "I think ... therefore it is". So tell us, in this instance what would be productive.A greater appreciation of empirical methods and application thereof, in exploration strategies.
I have concluded that this is largely missing in most conversations in this forum. This results in an imbalance, which then somehow results in the belief that theories drawn upon by Astrobiology, can somehow substitute for reality, (or existence), in the absence of empirical evidence. (It'll take some time to demonstrate exactly what I mean by that ... and why it is a flawed belief).


You persistance in insulting researchers and all others involved in Mars exploration with the implication that they are making wild, unsupported speculations or chasing ghosts (in the field of astrobiology) has tried my patience.You perceive insults? I suggest your perspective has resulted in that interpretation. Anything portrayed as science is open to interrogation. This is not an insult.

Astrobiology is currently about speculation. That's just the way it is.
Patience is a virtue.

ASTRO BOY
2013-May-06, 09:21 AM
Astrobiology is currently about speculation. That's just the way it is.
Patience is a virtue.


Actually all of science in general is about speculation, as well as Imagination, then forming hypothesis and then testing those hypothesis via experimentation and observation.
That's just the way it is........
Whether life exists on Mars in its most basic form is not confirmed yet one way or the other.
That doubt is and must be the imputus for continued science with whatever it takes....That's science, and is why those at the coal face are striving for more results to give greater clarity.



So far our little friends on the surface of Mars have confirmed water ice and shown conditions were at one time conducive to the possibilities of life.

Giving up on that search is not an option at this present time.

Selfsim
2013-May-06, 11:22 AM
Actually all of science in general is about speculation, as well as Imagination, then forming hypothesis and then testing those hypothesis via experimentation and observation.
That's just the way it is........Actually, when venturing into completely unexplored fields, the empirical methodology formally calls for large amounts of data to be accumulated before forming any speculative premise concerning the significance of the data, (or any expectations). Eventually, the investigation becomes less empirical and calls for more analysed, trended and historically condensed data. It also demands a high degree of your much beloved 'intuition' (from the investigator).

Your statement thus ignores this important and commonly adopted methodology in pure scientific research.

Experimental methodology requires sufficient knowledge of the variables involved. Different trials are strictly manipulated, so that inferences can be made as to causation of the observed change that results. This is precisely why the Viking experiments did not return conclusive results .. knowledge of the variables involved was incomplete and the GCMS calibration/sensitivity was set lower than the LR experiment's, as a result. In spite of later findings about why GCMS didn't detect organics, the Viking experience had already alerted many scientists as to just how ignorant science was about exo-life instrumentation/experimental design. Levin's investigations haven't altered this fundamental underlying issue, however.

This is the lesson learned, (by some), from Viking, and may well go some way to explaining why a follow-up mission has never eventuated, and why NASA has distanced itself from purely exo-life detection missions, since.
(I get the feeling that Levin however, puts it more down to politics and conspiracies. I suppose that's his prerogative .. but its a difficult one to swallow, don't you think?)

ASTRO BOY
2013-May-06, 09:09 PM
Actually, when venturing into completely unexplored fields, the empirical methodology formally calls for large amounts of data to be accumulated before forming any speculative premise concerning the significance of the data, (or any expectations). Eventually, the investigation becomes less empirical and calls for more analysed, trended and historically condensed data. It also demands a high degree of your much beloved 'intuition' (from the investigator).

Your statement thus ignores this important and commonly adopted methodology in pure scientific research.


No, that's fantasy on your part. There are many aspects of science that go hand in hand and make up the methodolgy you mention.
I recognise all of them and unlike you, I do not deride or sneer at any part of that methodolgy.
It's all part and parcel of what we know as science with plenty of evidence to back that view up.





Experimental methodology requires sufficient knowledge of the variables involved. Different trials are strictly manipulated, so that inferences can be made as to causation of the observed change that results. This is precisely why the Viking experiments did not return conclusive results .. knowledge of the variables involved was incomplete and the GCMS calibration/sensitivity was set lower than the LR experiment's, as a result. In spite of later findings about why GCMS didn't detect organics, the Viking experience had already alerted many scientists as to just how ignorant science was about exo-life instrumentation/experimental design. Levin's investigations haven't altered this fundamental underlying issue, however.




Oh, I totally agree, and this "uncertainty" and inconclusive results, are the prime reasons why continued research, experimentation and exploration must continue and I believe it will.








This is the lesson learned, (by some), from Viking, and may well go some way to explaining why a follow-up mission has never eventuated, and why NASA has distanced itself from purely exo-life detection missions, since.
(I get the feeling that Levin however, puts it more down to politics and conspiracies. I suppose that's his prerogative .. but its a difficult one to swallow, don't you think?)



Strange interpretations on your part. I do not believe NASA is distancing itself from any life detection missions or has ever done so.
They have a job to do with many aspects, and I believe they are doing that and achieving excellent results.
Levin has his own thoughts on the matter and I believe he feels strongly about them and I have some sympathy towards that view.
To say he is proceeding because of politics and conspiracies would to me seem be the view of someone else with another view and agenda.

TooMany
2013-May-06, 11:43 PM
Your statement thus ignores this important and commonly adopted methodology in pure scientific research.

Experimental methodology requires sufficient knowledge of the variables involved.

Different trials are strictly manipulated, so that inferences can be made as to causation of the observed change that results. This is precisely why the Viking experiments did not return conclusive results .. knowledge of the variables involved was incomplete and the GCMS calibration/sensitivity was set lower than the LR experiment's, as a result. In spite of later findings about why GCMS didn't detect organics, the Viking experience had already alerted many scientists as to just how ignorant science was about exo-life instrumentation/experimental design. Levin's investigations haven't altered this fundamental underlying issue, however.

This is the lesson learned, (by some), from Viking, and may well go some way to explaining why a follow-up mission has never eventuated, and why NASA has distanced itself from purely exo-life detection missions, since.
(I get the feeling that Levin however, puts it more down to politics and conspiracies. I suppose that's his prerogative .. but its a difficult one to swallow, don't you think?)

No you have it exactly backwards. Experimental methodology is used to gain knowledge of the variables involved. It takes lots of experiments to find out what's going on. You cannot preconceive a perfect experiment when you don't know what outcomes are possible. Sure we find out more about our ignorance by experimenting. That is no crime. Are you suggesting that you would have known how to do a much better experiment with the resources and knowledge available when the Viking project was building their experiment?

I don't know that NASA has "distanced" itself from life experiments. You should bear in mind that it's very important to their organization not to make fools of themselves in full view of the scientifically uneducated folks who control their funding. Remember the martian meteor? This is a real reason to take an extremely conservative approach in looking for evidence of past or present life on Mars. Another issue is that a negative result to existing life on Mars may give the funding folks an excuse to cut the missions without a thorough investigation of the possibility of life below surface or extinct life.

Given the conditions on Mars relative to what we know is life-friendly, surface life doesn't seem extremely probable, so it might be a fools errand for NASA to do some surface experiment and declare a negative result for life on Mars.

Don J
2013-May-07, 03:20 AM
The design of the GCMS should have catered for the detection of low concentration organics. Without this capability, no conclusions can be drawn.
Why was it not calibrated to detect lower levels of organics? Somewhere, someone decided on a set of assumed design parameters, which may not have been valid in the selected Martian testing environment. How/why did this occur?
The reason is that the GCMS was set to detect organic matter most scientists (still) believe exist on Mars (from meteoric impacts and infalls of interplanetary dust particles)


The GCMS instrument should have been capable of detecting organics in the sample area (if present).

If it wasn't, then clearly it wasn't capable of supporting the LR results, and thus the whole life detection strategy was flawed.
Ya can't have the type of life being targetted, without having organics present ... so we can't rely solely on the LR results, without the confirmation of organics.

No, the reason the CGMS was unable to detect organic matter in the Viking samples is because the CGMS was 8 orders of magnitude lower in sensitivity than the LR instrument for the reasons given above.


Taken together, the GCMS and LR results still lead to an inconclusive interpretation.

But it is strange that when NASA was aware for the fact that the CGMS was badly conceived they simply chosed to ignore that fact....and as you pointed out NASA rather chosed to distance itself from any other attempt at life detection on Mars?


Experimental methodology requires sufficient knowledge of the variables involved. Different trials are strictly manipulated, so that inferences can be made as to causation of the observed change that results. This is precisely why the Viking experiments did not return conclusive results .. knowledge of the variables involved was incomplete and the GCMS calibration/sensitivity was set lower than the LR experiment's, as a result. In spite of later findings about why GCMS didn't detect organics, the Viking experience had already alerted many scientists as to just how ignorant science was about exo-life instrumentation/experimental design.

It would have been easy to correct the GCMS calibration/sensitivity and send another Viking mission in the same area ...

Selfsim
2013-May-07, 07:29 AM
The reason is that the GCMS was set to detect organic matter most scientists (still) believe exist on Mars (from meteoric impacts and infalls of interplanetary dust particles)Yes .. that's what Levin's report said .. but a more cohesive strategy would have been for it to have been calibrated so it could have supported or falsified the LR results, eh?
(I think we might in loose agreement here?).

I suppose its easy to say this in arrears, some ~30 years later, and with the benefit of hindsight (and Levin's analysis) .. but it also wouldn't have been too hard to come up with that strategy initially, either.
I mean, doesn't: "two different teams built the instruments", show that they didn't have a cohesive strategy from the outset? (either that, or the mission had conflicting objectives (as far as the GCMS was concerned) .. ie: geologists wanted to see meteoric organics .. Astrobiologists wanted to see life (but don't worry about the organics ..)).

I personally don't 'blame' either camp. Viking, I think, was a premature attempt at testing exo-life hypotheses (and a rather expensive one at that).


No, the reason the CGMS was unable to detect organic matter in the Viking samples is because the CGMS was 8 orders of magnitude lower in sensitivity than the LR instrument for the reasons given above.Right .. but either way the GCMS results, (from the perspective from the LR results analysis team), was that there was no useful data (from GCMS) about the concentration of organics. So from their perspective, without that data, a fundamental piece of evidence was absent .. which ultimately thwarted the announcement of life. The net overall result is the same as if GCMS had detected no organics even if it had been calibrated at the same levels as the LR experiment.

The whole thing was just plain messed up primarily, (IMO), because of beliefs and expectations of what was believed would be found. (Perhaps by the sole geological focus of the GCMS experiment design .. but the mission wasn't solely about life detection, either ...).


But it is strange that when NASA was aware for the fact that the CGMS was badly conceived they simply chosed to ignore that fact....and as you pointed out NASA rather chosed to distance itself from any other attempt at life detection on Mars?Well, to be fair, the lesson learned was that exo-life detection, (if it is present), by using remotely managed probe based instrumentation, is highly prone to getting some or many of the variables incorrect, (the GCMS setting was Viking's particular issue) .. but it could have been just about anything else.
We have to remember almost nothing detailed was known about Mars' surface conditions before Viking, (in support of instrument calibrations, for eg). Hypothesis and theory led the way .. the lesson to be learned, is not to repeat this strategy (and unfortunately, many folk want to do exactly that).


It would have been easy to correct the GCMS calibration/sensitivity and send another Viking mission in the same area ...Well, I wouldn't say 'easy' .. and there still remains the distinct possibility that there is actually no life there. Patience is needed to properly answer this question if (for some reason) microbes are 'anticipated'. IMO, the search needs to take a back seat to environmental and geological data buildup, in order for its results to have a supportable context.

ASTRO BOY
2013-May-08, 12:41 AM
.. Astrobiologists wanted to see life (but don't worry about the organics ..))..


Yep, sure they do....But they also procede under the logical common sense rule...ie A Universe with the near infinite numbers and near infinite extent [if not infinite], coupled with homogenous and Isotropic observations of what we can see, that life other then on Earth should exist somewhere sometime.




I personally don't 'blame' either camp. Viking, I think, was a premature attempt at testing exo-life hypotheses (and a rather expensive one at that).

Why premature?


Again NASA may have made some mistakes [don't we all] but overall their road map to discovery and exploration should be supported and personal agendas locked away at this stage of proceedings.

The culmination of the robotic search and exploration of Mars will see the eventual manned mission....within 20 years I hope.
In the meantime the inconclusive results that have been obtained so far should be followed up on in all respects.

Don J
2013-May-08, 03:26 AM
Astrobiologists wanted to see life (but don't worry about the organics ..)).

Very unlikely, proof of that is that Viking was equipped with a third life detection instrument the Pyrolictic Release (PR)which detected that organic matter was continously produced on Mars although the signal detected by this instrument was insufficient to be considered evidence for life,it clearly showed the on-going production of organic matter.Page-6 of the PDF.
Post 1
http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf


Right .. but either way the GCMS results, (from the perspective from the LR results analysis team), was that there was no useful data (from GCMS) about the concentration of organics. So from their perspective, without that data, a fundamental piece of evidence was absent .. which ultimately thwarted the announcement of life. The net overall result is the same as if GCMS had detected no organics even if it had been calibrated at the same levels as the LR experiment.

Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.
Journal Of Geophysical Research PDF document:
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf


from post #74
There is now more data from Phoenix and other missions .. The Levin paper was published prior to Phoenix perchlorate results, also .. so it is now somewhat dated.


About perchlorate... from Phoenix update page:
http://martianchronicles.wordpress.com/2008/08/07/phoenix-update-pondering-perchlorates/
....
However, if the primary oxidizing agent is perchlorate, the news might not be quite so dire. Perchlorate is one of the slightly more benign oxidizers, since it tends to react more slowly than most. Also, if it was formed by breakdown of chloride salts at the surface, it probably is only present near the surface. Lower soil layers may not be as much at risk, and the deeper subsurface might be free of oxidants all together.

Selfsim
2013-May-09, 06:59 AM
Very unlikely, proof of that is that Viking was equipped with a third life detection instrument the Pyrolictic Release (PR)which detected that organic matter was continously produced on Mars although the signal detected by this instrument was insufficient to be considered evidence for life,it clearly showed the on-going production of organic matter.Page-6 of the PDF.
This result all depends on the type of oxidants present in the samples. One explanation was that oxidized iron, such as maghemite, could act as a catalyst to produce the results seen by the PR experiment.


Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.
Journal Of Geophysical Research PDF document:
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf


About perchlorate... from Phoenix update page:
http://martianchronicles.wordpress.com/2008/08/07/phoenix-update-pondering-perchlorates/
....
However, if the primary oxidizing agent is perchlorate, the news might not be quite so dire. Perchlorate is one of the slightly more benign oxidizers, since it tends to react more slowly than most. Also, if it was formed by breakdown of chloride salts at the surface, it probably is only present near the surface. Lower soil layers may not be as much at risk, and the deeper subsurface might be free of oxidants all together.The other thing I find annoying about most of these reports, is that they use the highly nebulous term 'organics'. There are many types of organic compounds .. many of which are not bio-organics at all.

The fact that both the GEX and PR experiments produced positive results even with the control sample, indicates that non-biological processes were at work in the soil.

Selfsim
2013-May-09, 12:02 PM
Just been reviewing the experiments and listening to some Levin YouTubes ...

The thing which strikes me the most is that the experiments are testing A LOT of theory interlaced with lots of speculative statements such as "hopefully consume the nutrient and give off gases" (etc). Even the so-called 'nutrients' were derived from organics produced in the original Miller-Urey experiments, which was only ever intended as a speculative analogue of Earth's early environment. Note that the idea that such an analogue was real and existed, is never questioned, in spite of it being an educated guess of what may have orginally existed at the time of life emergence on Earth. Did the same conditions ever exist to the same degree on Mars? Why would Martian micro-organisms, (or complex, UV-irradiated-for-eons ground chemistries - both inorganic and organic), react in the same way as Earth micro-organisms, when doused with such complex nutrient concoctions? Even Earthly contaminants were involved, too! My point is, that these experiments were conceived from some base chemical theory, (which is quite sound), interlaced with layers of hypotheses built on more hypotheses, built on .. "then hopefully if micro-organisms exist on Mars then hopefully ...", all of which is mostly just supposition.

And what happened? ... Ambiguity and unanticipated results.

Surely such ambiguous results (GEX, PR and the combined GEX, PR and LR ones), first and foremost, call into question the validity of the theory and speculations behind the experiment? Why not assume all this theory and speculation "which should have led to certain expected results", was basically in error, particularly in the case of Mars? Why the reluctance in scrutinising the hypothetical assumptions? Is this because we know we have insufficient data to support these speculations outside of Earth's pre-biotic and biotic environment (but no-one dares to bring that 'elephant-in-the-room' up!?!)

See, Levin was already convinced that his experiment technique was a 'winner' (on Earth for rapid detection of microbes). He was actually frustrated when it wasn't embraced in the other the US States, for testing water quality, (prior to his work for NASA). It seems he responded to this by lobbying to try it out on Mars .. and it returned his first ever ambiguous results. He certainly never questions all the life assumptions and speculations, which would probably support his views that his LR test actually detected Martian life, but what he's really saying is that his LR experiment detected Earth-life, because that's what his experimental design was built around ... not 'Martian-Life'.

Don J
2013-May-09, 02:01 PM
The other thing I find annoying about most of these reports, is that they use the highly nebulous term 'organics'. There are many types of organic compounds .. many of which are not bio-organics at all.

The Journal Of Geophysical Research make it clear that it is organic carbon.
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf
Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.



The fact that both the GEX and PR experiments produced positive results even with the control sample, indicates that non-biological processes were at work in the soil.
Can you point out to which control sample you are talking about with citation and reference ?Is the control sample giving exactly the same quantitative result?

Selfsim
2013-May-09, 10:15 PM
The Journal Of Geophysical Research make it clear that it is organic carbon.
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf
Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.Yeah .. but look at the organics they're talking about … chloromethane and dichloromethane. These things are industrial solvents like paint strippers, degreasers and aerosol propellants. Many represent toxicity to life, and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.

From the Navarro‐González et al paper, it looks as though could have been produced by various reactions which occured during the heating/reaction phase in the instruments themselves. They dismiss their idea however, that:
.. all the chloromethane was from a terrestrial source that formed in the TV oven from heating of chlorinated solvents or from adsorbed traces of methanol and HC1 Ie:
Since none of these compounds were detected at the same levels by the Viking Lander 1 instrument, it is unlikely that this was the source of CH3Cl.

I strongly recommend we stop using the general terms 'organic' and 'organic carbon' especially when we actually know what specific chemicals were detected.

I have a sneaking suspicion that this mis-use of the term term 'organic' in the hunt for exo-life, (eg: Mars), is deliberately being used to suggest 'life'. This is inappropriate when there are so many missing pathways, which have no supporting evidence for their presence in that environment).

The peer reviewed papers are specific .. but cursory glimpses by, and extraction of words that resonate with 'armchair' Astrobiologists, appears to be a major source of confusion.


Can you point out to which control sample you are talking about with citation and reference ?Is the control sample giving exactly the same quantitative result?The source I'm quoting from admittedly, was not peer reviewed (in confirmation to your previous point of such). See the 'Results' summary section towards the end.

This report was written for a space instrumentation (commercial) site by: Michael Caplinger, Malin Space Science Systems called "Life on Mars" (http://www.msss.com/http/ps/life/life.html) He is a specialist in Mars instrument design engineering. He was employed by Malin Space Science Systems (MSSS) which designs, builds, and operates space camera systems for NASA and commercial aerospace customers. Malin himself has been intimately involved in Mars and Space System Investigation roles for decades.

Admittedly the paper was written in 1995, but it appears to summarise accurately much of the (somewhat dated) 'consensus mainstream' position detail, also elaborated upon in the Life on Mars Wiki page. (I chose this document 'cause it was a little easier reading and had a nice summary of the complexity .. but I don't limit my position on that basis alone).

ASTRO BOY
2013-May-09, 10:49 PM
The Curiosity Rover like the other Mars Landers and Rovers in the past has pursued four main science goals and objectives.......

[1] To determine whether life ever did arise on Mars and indeed if it still exists.

[2]Characterize the Martian climate, now and in the distant past

[3]Determine the Martian geology

[4] To prepare the way for a manned mission to the red planet.

BioSci
2013-May-09, 10:51 PM
Yeah .. but look at the organics they're talking about … chloromethane and dichloromethane. These things are industrial solvents like paint strippers, degreasers and aerosol propellants. Many represent toxicity to life, and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.


Uh, that is the standard definition of organic compounds (from wiki):
"An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon (such as CO and CO2), and cyanides, as well as the allotropes of carbon such as diamond and graphite, are considered inorganic. The distinction between "organic" and "inorganic" carbon compounds, while "useful in organizing the vast subject of chemistry... is somewhat arbitrary".[1]

Basically, other than a few very simple compounds, if it contains C it is defined as "organic" no matter the source.

Selfsim
2013-May-10, 12:12 AM
Uh, that is the standard definition of organic compounds (from wiki):
"An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon (such as CO and CO2), and cyanides, as well as the allotropes of carbon such as diamond and graphite, are considered inorganic. The distinction between "organic" and "inorganic" carbon compounds, while "useful in organizing the vast subject of chemistry... is somewhat arbitrary".[1]

Basically, other than a few very simple compounds, if it contains C it is defined as "organic" no matter the source.Yes .. and even isotopic characterisation doesn't necessarily definitively distinguish organic from inorganic. The isotopic ratios of the carbon in the above mentioned compounds, is usually used on Earth to determine whether the sample is 'consistent with' exposure to typical bio-metabolic processes, or is more 'consistent with' exposure to inorganic/geological processes. This ultimately has to do with how we know the C3/C4 fixation processes work in Earth biology. There is no reason to assume this is the way it would work on Mars .. after all we don't see any plants there at present, for starters, do we?

This method is also used to relate the sample to a water source. This is what is presently under test by sending isotopic detection gear along on Curiosity .. (that, and trying to backtrack from a sample to its apparent liquid water origins). The method is also used to infer that a sample may have a terrestrial or deep space source .. (the latter becoming evident when comparing the ratio of C13/C14, (from memory), in a sample against the vast empirical database built up from Earth samples which we know are 'living'). If it isn't within the same range, then it is usually excluded from considerations of terrestrial origins and therefore inferred to be from space-based origins (we're talking comet and asteroid fragments here ..).

Mostly in comet fragment analysis, the presence of nitrogen and aliphatic hydrocarbons with longer chain lengths, is what they look for. Spectroscopic analysis from comet tail observations, permits confirmation of this from an independent source. Glycine is one such long chain organic molecule, which enters into the 'radar screen' as being of mild interest (and its a looong way from a humble dichloromethane molecule!)

Footnote (for Don J): Barring any inaccuracies in my recollections, all of what I say above comes from many reputable peer-reviewed source documents. (I understand much you favor that aspect). I am not just speaking opinions here. I'm happy to distinguish opinionated parts if I've missed any … just point 'em out if you like, and we can roll onwards from there.

Don J
2013-May-10, 12:41 AM
Yeah .. but look at the organics they're talking about … chloromethane and dichloromethane. These things are industrial solvents like paint strippers, degreasers and aerosol propellants. Many represent toxicity to life, and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.


If you look carefully at the study you will notice that the Earth sample of (Mars like soil) from the Chilian Atacama desert containing 32 +or - 6ppm organic carbon also produce chloromethane and dichloromethane when mixed with 1 wt% magnesium perclhorate and heated at 500 degree celcius using the same Viking detection protocols. That is from these results that a chemical kinetics model was developped to predict the level of oxidation and chlorination of organics in the Viking oven.From that chemical kinetics model they were able to determine the level of perchlorate and organic carbon from the reevaluation of the Viking results.
First chapter (Abstract)...
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf

Selfsim
2013-May-10, 01:39 AM
If you look carefully at the study you will notice that the Earth sample of (Mars like soil) from the Chilian Atacama desert containing 32 +or - 6ppm organic carbon also produce chloromethane and dichloromethane when mixed with 1 wt% magnesium perclhorate and heated at 500 degree celcius using the same Viking detection protocols. That is from these results that a chemical kinetics model was developped to predict the level of oxidation and chlorination of organics in the Viking oven.From that chemical kinetics model they were able to determine the level of perchlorate and organic carbon from the reevaluation of the Viking results.
First chapter (Abstract)...
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf.. And so? … (I'm missing your point here).

Don J
2013-May-10, 03:10 AM
.. And so? … (I'm missing your point here).
Sorry, for the lack of precision.That was in reply to that sentence that i split in two part...


Many represent toxicity to life, and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.

My point is that the paper demonstrated that -chloromethane and dichloromethane- are a by-product caused by the decomposition of the perchlorate when heated at 200+ degree celsius ...page 7 pdf
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf

So even if -chloromethane and dichloromethane- was detected in the Martian samples there is no toxicity for the organics or living matter of Mars soil at ambient Mars temperature.

Now about the other part of your sentence:


and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.

The reevaluation of the Viking GCMS datas demonstrate the presence of organic carbon in the Martian soil.
Thus certainly that give relevance to the presence or absence of microbial life functions when combined with the LR positive life detection results.

Selfsim
2013-May-10, 11:45 AM
Sorry, for the lack of precision.That was in reply to that sentence that i split in two part...

My point is that the paper demonstrated that -chloromethane and dichloromethane- are a by-product caused by the decomposition of the perchlorate when heated at 200+ degree celsius ...page 7 pdf
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf

So even if -chloromethane and dichloromethane- was detected in the Martian samples there is no toxicity for the organics or living matter of Mars soil at ambient Mars temperature.

Now about the other part of your sentence:

The reevaluation of the Viking GCMS datas demonstrate the presence of organic carbon in the Martian soil.
Thus certainly that give relevance to the presence or absence of microbial life functions when combined with the LR positive life detection results.Ok .. got ya, now.

Hmm ... the LR was the only experiment which didn't use a TV oven (except for deliberate sterilisation of the control sample ... with a subsequent negative result in the uptake of the Labelled C14 isotope .. which is to be expected from heat-killed microbes, eh?)

Interestingly too, the recent Curiosity results from Rocknest (dated March 12) ... (http://www.nasa.gov/mission_pages/msl/news/msl20121203.html)

SAM tentatively identified the oxygen and chlorine compound perchlorate. This is a reactive chemical previously found in arctic Martian soil by NASA's Phoenix Lander. Reactions with other chemicals heated in SAM formed chlorinated methane compounds -- one-carbon organics that were detected by the instrument. The chlorine is of Martian origin, but it is possible the carbon may be of Earth origin, carried by Curiosity and detected by SAM's high sensitivity design....a design which I believe makes use of TV ovens too, eh?
I guess these results are also entirely consistent with the outcomes of the Viking studies, too.
Hmm .. I wonder if they conducted contamination tests on the SAM instruments whilst in transit(?) We already know the drill bit escaped decontamination procedures before it left .. but it seems they used the soil scoop at Rocknest.

Interesting .... however ...

"We have no definitive detection of Martian organics at this point, but we will keep looking in the diverse environments of Gale Crater," said SAM Principal Investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md.See what I mean about how confusing this term 'organics' is? Here we have in one sentence that perchlorate (tentatively) and chlorinated methane compounds have been found .. but no 'organics'.
Clearly 'organics' is being used as a placeholder for more complex life, (or past life), relevant bio-organics. But if they're using TV Ovens in the SAM/GCMSs, then they're going to have the same 'desensitisation' outlined in the papers we've discussed. (Which I think, is the point you've been making all along, eh?) I would think any self-respecting martian microbe would turn its toes up and detroy any evidence of its makeup in this heating process.

It looks almost like a $2.5bill blunder, when coming from the Gonzales (et al dated 2010) and Levin dissertations (ongoing since the 1990s). According to these papers, Curiosity will never detect organics if they keep heating the samples. Any mission making use of the TV ovens in their MSs since Viking, would have been a huge, sustained blunder over the last 40 years, too! ..

Gee, not much wonder no-one wants to listen to Levin! It seems they'd be extraordinarily lucky to get another cent in funding for life detection for ages, if what he's been saying about his LR process is right!?! (Provided the martian 'organics' do in fact, turn out to be/have been 'life', of course ... ;) )

Colin Robinson
2013-May-10, 10:27 PM
Interesting .... however ...

"We have no definitive detection of Martian organics at this point, but we will keep looking in the diverse environments of Gale Crater," said SAM Principal Investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md.
See what I mean about how confusing this term 'organics' is? Here we have in one sentence that perchlorate (tentatively) and chlorinated methane compounds have been found .. but no 'organics'.
Clearly 'organics' is being used as a placeholder for more complex life, (or past life), relevant bio-organics.

Please look more closely at the words you've quoted from Paul Mahaffy. "no definitive detection of Martian organics".

I think what he's saying is: Yes, Curiosity detected small amounts of organic compounds (chorinated methane molecules) unfortunately we are not yet sure whether these are local Martian organics, or whether they are contaminants, i.e. compounds which Curiosity itself carried to Mars from Earth.

Look at this way, I don't think his comments show anything about the word "organics" being confusing. Anyone who doesn't know what organic molecules are, can find the answer in seconds from online sources like Wikipedia.

Don J
2013-May-11, 12:31 AM
Ok .. got ya, now.

Hmm ... the LR was the only experiment which didn't use a TV oven (except for deliberate sterilisation of the control sample ... with a subsequent negative result in the uptake of the Labelled C14 isotope .. which is to be expected from heat-killed microbes, eh?)

The thing you forgot to mention is that the control sample was used after the LR instrument detected a positive result on a sample at Martian ambient temperature ... thus the negative result obtained after heating the control sample to "sterilize" it have revealed that the positive result was not caused by a chemical reaction.

Here the protocol explained:


Should a positive response be obtained, a duplicate sample of the same soil would be heated to "sterilize" it. It would then be tested as a control and should it still show activity similar to the first response, that was evidence that the activity was chemical in nature. However, a nil, or greatly diminished response, was evidence for biology. This same control was to be used for any of the three life detection experiments that showed a positive initial result.

Text in context
http://en.wikipedia.org/wiki/Viking_spacecraft_biological_experiments


Labeled Release

(PI: Gilbert Levin, Biospherics Inc.) The Labeled Release (LR) experiment is the one that gave the most promise for the exobiologists. In the LR experiment, a sample of Martian soil was inoculated with a drop of very dilute aqueous nutrient solution. The nutrients (7 molecules that were Miller-Urey products) were tagged with radioactive 14C. The air above the soil was monitored for the evolution of radioactive 14CO2 gas as evidence that microorganisms in the soil had metabolized one or more of the nutrients. Such a result was to be followed with the control part of the experiment as described for the PR(Pyrolytic Release) below. The result was quite a surprise following the negative results of the first two tests, with a steady stream of radioactive gases being given off by the soil immediately following the first injection. The experiment was done by both Viking probes, the first using a sample from the surface exposed to sunlight and the second probe taking the sample from underneath a rock; both initial injections came back positive.
..........
Should a positive response be obtained, a duplicate sample of the same soil would be heated to "sterilize" it. It would then be tested as a control and should it still show activity similar to the first response, that was evidence that the activity was chemical in nature. However, a nil, or greatly diminished response, was evidence for biology. This same control was to be used for any of the three life detection experiments that showed a positive initial result.

Selfsim
2013-May-11, 09:47 AM
Well, Ok ... so if the negative control result supposedly rules out 'chemical reactions' as the cause of the positive LR result, then why were the 'martian organics' not detected by Curiosity's SAM?

Reading further, apparently, Curiosity uses a different technique ...
Martian Life Could Have Evaded Detection by Viking Landers (http://www.space.com/3038-martian-life-evaded-detection-viking-landers.html) ...

"Our study clearly demonstrates that future Mars missions should include other methodologies in addition to this one to detect extinct or extant life on Mars," Navarro-Gonzalez told SPACE.com.

He added that NASA's Mars Science Laboratory (MSL), scheduled to launch in 2009, will not have the same limitations as the Viking landers because it will analyze the Martian soil in a slightly different way. "The problem is how to get the organics from soil to the spectrometer," Navarro-Gonzalez said. "Viking used the heating process. The MSL will extract organic compounds using solvents first and then volatize them chemically" before analysis.

"With MSL, we expect to be sensitive to a substantially broader range of organic molecules than Viking..." said Paul Mahaffy of NASA Goddard Space Flight Center in Maryland, the principal investigator for the mission's sample and analysis instrument.

For one thing, the MSL's Sample Analysis at Mars (SAM) experiment will be able to heat samples much higher than 500 degrees Celsius. "That was the temperature limit for the Viking GC-MS experiment and this may be an issue for organic molecule extraction from some samples," Mahaffy said.The hunt goes on ... and there may be some chance yet.

Aside: Somewhere in all these papers I read that they have confirmed that the chorine species being detected, is definitely of martian origin (can't find the words .. will have another look when I get the chance). I was not aware that isotopic detection of Chlorine was amongst SAM's capability set(?)

Might do some further digging on just exactly what organics SAM is capable of detecting ... (will return to this shortly).

Selfsim
2013-May-11, 10:42 AM
So, Emily (Lakdawalla ) to the rescue ...
(http://www.planetary.org/blogs/emily-lakdawalla/2012/curiosity-instrument-sam.html)

SAM is required to obtain specific data sets to specific performance levels.


Inventory volatile organic compounds in rocks and soils, measuring anything that's more abundant than a few parts per billion (by mass).
Measure the distribution of molecular weights and chemical structures for organic compounds in rocks and soils. Wet chemistry analysis will be required to get at some of these. SAM is required to inventory compounds containing everything up to 20 carbons.
Inventory certain specific astrobiologically interesting molecules including amino acids, amines, and carboxylic acids.
Measure the carbon-13/carbon-12 ratio in refractory carbon compounds. This is where the combustion analysis comes in. SAM is required to measure abundances of such refractory compounds to the part-per-million level.
Measure the distribution of oxidation states of organic compounds. This gets at the environmental conditions that prevailed when they formed.
Inventory and temperature-profile volatile inorganic compounds in rocks and soils. This will get at abundances of certain minerals present in the rocks, like carbonates, sulfates, and clays, to the part-per-million level.
Measure the abundance and carbon-13/carbon-12 ratio of methane.
Measure how atmospheric gas concentrations vary over the course of a sol and over the course of Mars' seasons.
Measure the relative abundances and isotopic ratios of the noble gases argon, neon, xenon, and krypton. There are specific precision levels required for all these abundances and ratios ...


So, 'organics' becomes more clearly defined with the above specs!

We're talkin' some serious bio-organics, here folks - up to 20 carbon atoms .. thus inclusive of 'interesting' amino acids!
(Mind you, it looks like they might not be able to easily distinguish non-meteroic origins for certain bio-carbon compounds, on the basis of SAM results alone).

Note that Navarro-Gonzalez must have been referring to SAM's Wet Chemistry front end to the GC-MS. Notice that the solvents break up bigger molecules into smaller ones, then pass them onto to a low temperature incubator, so that the GC-MS can then analyse the products. This I would think, significantly improves the chances of avoiding the problems which arose with the Viking TV-GCMS.

Only problem is .. where are these larger chain martian organics?
If Curiosity's first SAM sample was as similar to Vikings and Phoneix's, including the detection of the expected (di)chloromethane products, (presumably, the 'chlorinated methane compounds' referred to a couple of posts back?), then why hasn't the wet front end process resulted in them being detected and classified in Curiosity's first SAM sample?

Selfsim
2013-May-11, 10:50 AM
Aside: Somewhere in all these papers I read that they have confirmed that the chorine species being detected, is definitely of martian origin (can't find the words .. will have another look when I get the chance). I was not aware that isotopic detection of Chlorine was amongst SAM's capability set(?)Oops ... 'twas in the quote I, myself, included in post #94, from the NASA Curiosity web page. I'm not clear on what evidence they have for the chlorine being of 'martian origin', if SAM isn't designed to measure chlorine isotopes(?) I think either Navarro-Gonzalez (etal) or Levin brought this shortcoming up, in the previously papers on Viking's instruments, too(?)

Selfsim
2013-May-11, 11:36 AM
Please look more closely at the words you've quoted from Paul Mahaffy. "no definitive detection of Martian organics".

I think what he's saying is: Yes, Curiosity detected small amounts of organic compounds (chorinated methane molecules) unfortunately we are not yet sure whether these are local Martian organics, or whether they are contaminants, i.e. compounds which Curiosity itself carried to Mars from Earth.

Look at this way, I don't think his comments show anything about the word "organics" being confusing. Anyone who doesn't know what organic molecules are, can find the answer in seconds from online sources like Wikipedia.Well, I'm reassured that Emily also recognises the problem with the usage of the term ...

... Before I begin, though, I want to talk about a problematic word: "organic." Look up definitions of "organic" on the Web and a great many of them circle around to life. But when a space scientist talks about organic compounds, usually all they mean is a compound that contains carbon and hydrogen. So carbon dioxide, diamond, and cyanides are not organic, but hydrocarbons (methane, ethane, propane, etc...) and alcohols and amino acids are. The Wikipedia entry on organic chemistry discusses the problematic, occasionally arbitrary, and often not-very-useful nature of this hair-splitting. So I'm going to use a different phrase, "carbon-containing compounds," because that's really what we're talking about here.
...
Then from the NASA curiosity article ..

SAM tentatively identified the oxygen and chlorine compound perchlorate. This is a reactive chemical previously found in arctic Martian soil by NASA's Phoenix Lander. Reactions with other chemicals heated in SAM formed chlorinated methane compounds -- one-carbon organics that were detected by the instrument. The chlorine is of Martian origin, but it is possible the carbon may be of Earth origin, carried by Curiosity and detected by SAM's high sensitivity design.So, maybe the chlorine is deduced to have come from the perchlorate (fair enough - no isotopic analysis required here to necessarily establish its martian-ness), but why can't they figure out where the carbon came from, by its SAM based isotopic ratio analysis?
Surely there's got to be carbon in a scoop of martian soil somewhere? I mean .. the atmosphere is primarily carbon-based isn't it .. we already know that mars got meteoric carbon the same way Earth did .. so why the procrastination about the martian-ness of the carbon component here?
Frustrating!

Selfsim
2013-May-11, 12:15 PM
And then ... Chlorinated Forms of Methane at 'John Klein' Site ... (http://www.nasa.gov/mission_pages/msl/multimedia/pia16836.html)

NASA's Curiosity rover has detected the simple carbon-containing compounds chloro- and dichloromethane from the powdered rock sample extracted from the "John Klein" rock on Mars.
...
Both chloro- and dichloromethane were also detected earlier by SAM at the "Rocknest" drift. It is possible that these simple carbon-containing compounds were produced by the reaction between Martian carbon and chlorine released when this sample was heated in the SAM oven. However, analysis of an additional drilled sample is required to help scientists understand if instead any residual terrestrial carbon from the drill, or perhaps chlorine left over from the Rocknest sample, is responsible for the generation of some or all of these compounds.So now they're using the term 'simple carbon-containing compounds' ... because that's all they detected via SAM at both sites (Klein and Rocknest)

So, all this talk of 'organics', (in the previous Viking discussion and papers), is easily explained by 'the reaction between Martian (perhaps) carbon and chlorine released when this sample was heated in the SAM oven'.

Looks like this one might have the usual Astrobiology hype at its heart, (which frequently creates obfuscation by conflating terminologies ... in this case the term 'organics', instead of the reality of: 'simple carbon-containing compounds').

I wonder where Prof Levin now stands in the light of this?

Don J
2013-May-11, 07:35 PM
And then ... Chlorinated Forms of Methane at 'John Klein' Site ... (http://www.nasa.gov/mission_pages/msl/multimedia/pia16836.html)


NASA's Curiosity rover has detected the simple carbon-containing compounds chloro- and dichloromethane from the powdered rock sample extracted from the "John Klein" rock on Mars.
...
Both chloro- and dichloromethane were also detected earlier by SAM at the "Rocknest" drift. It is possible that these simple carbon-containing compounds were produced by the reaction between Martian carbon and chlorine released when this sample was heated in the SAM oven. However, analysis of an additional drilled sample is required to help scientists understand if instead any residual terrestrial carbon from the drill, or perhaps chlorine left over from the Rocknest sample, is responsible for the generation of some or all of these compounds

So now they're using the term 'simple carbon-containing compounds' ... because that's all they detected via SAM at both sites (Klein and Rocknest)

So, all this talk of 'organics', (in the previous Viking discussion and papers), is easily explained by 'the reaction between Martian (perhaps) carbon and chlorine released when this sample was heated in the SAM oven'.

Looks like this one might have the usual Astrobiology hype at its heart, (which frequently creates obfuscation by conflating terminologies ... in this case the term 'organics', instead of the reality of: 'simple carbon-containing compounds').

I wonder where Prof Levin now stands in the light of this?
I suppose that as a wise men he will wait for all the tests planned for the mission and verifications been done before making any comments.
However here what he have to say about the Curiosity mission instruments capability. No need to say that he is watching the mission with great interest.He have also proposed some tests for the highly sophisticated camera aboard Curiosity.

Stealth Life Detection Instruments Aboard Curiosity
http://www.gillevin.com/Mars/SPIE_2012_As_Accepted_8-27-12.pdf

ASTRO BOY
2013-May-11, 11:22 PM
I suppose that as a wise men he will wait for all the tests planned for the mission and verifications been done before making any comments.
However here what he have to say about the Curiosity mission instruments capability. No need to say that he is watching the mission with great interest.He have also proposed some tests for the highly sophisticated camera aboard Curiosity.

Stealth Life Detection Instruments Aboard Curiosity
http://www.gillevin.com/Mars/SPIE_2012_As_Accepted_8-27-12.pdf


Interesting paper.....
If we happen to find basic microbrial/bacteria life on Mars, will we be able to differentiate as to whether it evolved on Mars when conditions were suitable, or whether it could have been deposited via Panspermia?

Selfsim
2013-May-12, 09:08 AM
I suppose that as a wise men he will wait for all the tests planned for the mission and verifications been done before making any comments.
However here what he have to say about the Curiosity mission instruments capability. No need to say that he is watching the mission with great interest.He have also proposed some tests for the highly sophisticated camera aboard Curiosity.

Stealth Life Detection Instruments Aboard Curiosity
http://www.gillevin.com/Mars/SPIE_2012_As_Accepted_8-27-12.pdfThanks for that.

Well, its all there, eh?

An explicit ban ...
NASA has often stated (e.g. MSL Science Corner) that it’s Mars Science Laboratory (MSL), “Curiosity,” Mission
to Mars carries no life detection experiments. This is in keeping with NASA’s 36-year explicit ban on such, imposed immediately after the 1976 Viking Mission to Mars.I was unaware of any officially, explicit, deliberate life testing 'bans' ... My understanding was that life testing could still be integrated within overall probe science goal testing programs, (wherever it can be physically accommodated inside the usual probe payload constraints). Are there any other more 'official' references to this 'ban'? (Or is this just Levin adding some 'color' to issue?)

... Then seemingly subterfuge, in order to circumvent that 'ban', by the use of 'stealth instruments'(??) ...

Curiosity’s stealth instruments are those seeking organic compounds, and the mission’s high-resolution camera system.Then the totally confident speculative premonition:
Hopefully, its stealth confirmations of life will be reported shortly.

Very strong ATM vibes there .. but so what, I ask? 'ATM' is nothing to be feared, or run from! Scientific consensus needs to stand on its merits .. or die!
In this particular case, he's done the work, covered many of the bases, and followed the countering views as far as is possible (IMO). In this case, there is hardcore scientific disagreement and now, productive, tests aboard Curiosity, which should be capable of detecting the 'molecules of interest', (including bio-organics if they exist), all which is good for scientific progress. Good on him.

I can't help but feel that the concepts we assign to 'metabolism', and its automatic association with bio-organics and life, may well turn out to be at stake here. Similarly, our concepts of how carbon compounds behave in a perfectly definable, yet atypical environment, might also be 'on the table'. Complexity in a natural environment has a way of catching expectations out, time and time again. The thing it catches out, is the predeterminism developed by the relative feeling of security, which consensus (mainstream) science affords those who adopt it because of who speaks it, rather than the principles it is based upon. Lab testing controls the surrounding environment, and constrains the known variables. Natural environments don't often work that way, and the intricate variations can make all the difference to the outcome. (This is already well known science).

He also (at least) acknowledges other options:
The LR results are not a snapshot, as are the “biomarkers,” but are long-term, continuous evidence of metabolism, as confirmed by metabolism-killing controls. Objectors would be driven to the sometimes proposed concept that chemistry on Mars differs from chemistry on Earth, that some mysterious reaction, not yet achievable in laboratories, is mimicking life. This would be a difficult case to make before competent chemists and physicists. One doesn't have to 'object' to anything, in order for the underlined part of this statement, to still be valid. Similarly, there is no need for 'mysteriousness', either. The case would be difficult to make because there would be no precedent to back it up. This is surely the nature of research and exploration .. and this is surely what Curiosity was created to investigate and uncover(?)

And what will happen if no 'bio-organics', or other other 'carbon-containing' molecules 'of interest', (and at cause), are found during SAM/Curiosity's usable lifetime?

What point is there in speculating more about all this? My view, is ... very little .. (aka zilch).

More progressive data gathering, testing, and a deliberate willingness to 'go where the data leads' is the tried and tested solution.

Don J
2013-May-12, 06:34 PM
Thanks for that.

Well, its all there, eh?

An explicit ban ...I was unaware of any officially, explicit, deliberate life testing 'bans' ... My understanding was that life testing could still be integrated within overall probe science goal testing programs, (wherever it can be physically accommodated inside the usual probe payload constraints). Are there any other more 'official' references to this 'ban'? (Or is this just Levin adding some 'color' to issue?)

You seemed well aware about some aspect of this "ban"some posts ago...So whatever the "ban" word be officially used by NASA or not the result is the same -No other life detection mission on Mars after Viking ...
You wrote in post 77

This is the lesson learned, (by some), from Viking, and may well go some way to explaining why a follow-up mission has never eventuated, and why NASA has distanced itself from purely exo-life detection missions, since.


... Then seemingly subterfuge, in order to circumvent that 'ban', by the use of 'stealth instruments'(??) ...

That is not what Levin is implying by "stealth -life detection- instruments".He said that the sensitivity of these instruments are now equal to the level of sensitivity of his LR instrument.The real "stealth life detection instrument " is his positive life detection results from the LR instrument aboard Viking.
Then, when finally there will be detection of organic matter by the Curiosity rover that will confirm that his LR results were valid and that there is living microorganisms in the Martian soil


Then the totally confident speculative premonition:

Which is based on the extremely good sensibility of the instruments for detecting organic matter.


Very strong ATM vibes there .. but so what, I ask? 'ATM' is nothing to be feared, or run from! Scientific consensus needs to stand on its merits .. or die!
In this particular case, he's done the work, covered many of the bases, and followed the countering views as far as is possible (IMO). In this case, there is hardcore scientific disagreement and now, productive, tests aboard Curiosity, which should be capable of detecting the 'molecules of interest', (including bio-organics if they exist), all which is good for scientific progress. Good on him.

I can't help but feel that the concepts we assign to 'metabolism', and its automatic association with bio-organics and life, may well turn out to be at stake here. Similarly, our concepts of how carbon compounds behave in a perfectly definable, yet atypical environment, might also be 'on the table'. Complexity in a natural environment has a way of catching expectations out, time and time again. The thing it catches out, is the predeterminism developed by the relative feeling of security, which consensus (mainstream) science affords those who adopt it because of who speaks it, rather than the principles it is based upon. Lab testing controls the surrounding environment, and constrains the known variables. Natural environments don't often work that way, and the intricate variations can make all the difference to the outcome. (This is already well known science).

He also (at least) acknowledges other options:


The LR results are not a snapshot, as are the “biomarkers,” but are long-term, continuous evidence of metabolism, as confirmed by metabolism-killing controls. Objectors would be driven to the sometimes proposed concept that chemistry on Mars differs from chemistry on Earth, that some mysterious reaction, not yet achievable in laboratories, is mimicking life. This would be a difficult case to make before competent chemists and physicists.

One doesn't have to 'object' to anything, in order for the underlined part of this statement, to still be valid. Similarly, there is no need for 'mysteriousness', either. The case would be difficult to make because there would be no precedent to back it up. This is surely the nature of research and exploration .. and this is surely what Curiosity was created to investigate and uncover(?)

And what will happen if no 'bio-organics', or other other 'carbon-containing' molecules 'of interest', (and at cause), are found during SAM/Curiosity's usable lifetime?

What point is there in speculating more about all this? My view, is ... very little .. (aka zilch).

More progressive data gathering, testing, and a deliberate willingness to 'go where the data leads' is the tried and tested solution.


One doesn't have to 'object' to anything, in order for the underlined part of this statement, to still be valid.

What he said about the "objectors" is that even if complex organic compounds were find on Mars the Objectors would always be driven to the sometimes proposed concept (remember that rethoric was used for Viking LR positive life detection results) that because chemistry on Mars differs from chemistry on Earth, that some mysterious (chemical) reaction, not yet achievable in laboratories, is mimicking life.This would be a difficult case to make before competent chemists and physicists.

Selfsim
2013-May-12, 11:25 PM
You seemed well aware about some aspect of this "ban"some posts ago...So whatever the "ban" word be officially used by NASA or not the result is the same -No other life detection mission on Mars after Viking ...
You wrote in post 77 … Well, 'reluctancy' is somewhat different in motivation from outright 'bans', eh? And its clear that Curiosity can detect molecules of 'considerable interest', (if they exist in its search zones) .. so, I wouldn't exactly say that means 'no other life detection equipment will be sent to Mars' would you?


That is not what Levin is implying by "stealth -life detection- instruments".He said that the sensitivity of these instruments are now equal to the level of sensitivity of his LR instrument.The real "stealth life detection instrument " is his positive life detection results from the LR instrument aboard Viking.
Then, when finally there will be detection of organic matter by the Curiosity rover that will confirm that his LR results were valid and that there is living microorganisms in the Martian soilLR was designed to imply terrestrial metabolism because that's a key part of our definition of 'life'. That part of the definition is as much 'up for grabs' as anything else, in the light of there being no past exo-life data to draw from, in forming conclusions. There are many other aspects which define life, which haven't yet been tested on a martian sample. I usually cite the example of recent tests (http://cosmoquest.org/forum/showthread.php?140063-How-Small-Can-Life-Be&p=2086479#post2086479) performed on what was thought to be 'nanobacteria' (some 15 or so of them). The result enabled them to rule out the samples as 'living entities', and associate them more closely with self-propagating mineral-fetuin complexes, dubbed 'nanons'.

There's quite a way to go (beyond Levin's LR tests), in order to declare 'life', (let alone more specifically, 'living micro-organisms').


Which is based on the extremely good sensibility of the instruments for detecting organic matter.Or, (somewhat more precisely), the ability of SAM's instrumentation to inventory compounds containing everything up to 20 carbons and interesting molecules including amino acids, amines, and carboxylic acids.


What he said about the "objectors" is that even if complex organic compounds were find on Mars the Objectors would always be driven to the sometimes proposed concept (remember that rethoric was used for Viking LR positive life detection results) that because chemistry on Mars differs from chemistry on Earth, that some mysterious (chemical) reaction, not yet achievable in laboratories, is mimicking life.This would be a difficult case to make before competent chemists and physicists.Well, nanobacteria and nanobes have kept a few guessing .. so why would what's been detected be any different from that?

At the end of the day, more data gathering is needed, and some of that data might require complex tasks to be performed and observed by an onsite human .. but I can't see a mission of such complexity and risk being undertaken on the sole basis of a positive Viking LR test result (IMO).

Don J
2013-May-13, 01:24 AM
At the end of the day, more data gathering is needed, and some of that data might require complex tasks to be performed and observed by an onsite human .. but I can't see a mission of such complexity and risk being undertaken on the sole basis of a positive Viking LR test result (IMO).
Why the need of sending a human mission to Mars?
Lets suppose that the Viking LR positive life detection results is backed by a positive detection of organic matter by Curiosity,
a robotic mission to collect sample(s) and return mission of Martian soil sample(s) to be examined on Earth by biologists whatever it came from one of the Viking landing site or from a Curiosity location, is far more easy and less costly.The only way that a human mission is needed is if they determine that there may be a risk of contamination of Earth with Martian living microbes.

Selfsim
2013-May-13, 02:44 AM
Why the need of sending a human mission to Mars?
Lets suppose that the Viking LR positive life detection results is backed by a positive detection of organic matter by Curiosity,
a robotic mission to collect sample(s) and return mission of Martian soil sample(s) to be examined on Earth by biologists whatever it came from one of the Viking landing site or from a Curiosity location, is far more easy and less costly.The only way that a human mission is needed is if they determine that there may be a risk of contamination of Earth with Martian living microbes.Yeah ... maybe. Levin (for eg) isn't even proposing going that far, either eh?
(Ie: bio-sampling 'dart' drops, etc).

Apart from emotive/philosophical issues, the task complexity is presently what ultimately drives the need for onsite human intervention/presence .. over robotics.

This in turn, would then be driven by the nature of such a finding.
To enable uncertainties to be eliminated, (allowing for unambiguous results), a certain level of testing complexity would have to be involved. (Eg: compare with ~15 tests for nanobacteria … and we knew precisely where they lived, beforehand!)

I think the complexity of the Viking tests, and the possible permutations arising immediately following the results, is a good example of how human presence could perhaps, have been used to mitigate most experimental ambiguities, (albeit at a cost).

I think the cost of these missions is great enough, that there needs to be other research goals, beyond just the investigation of any old 'organics'. As much as some folk have convinced themselves that finding complex bio-organics would be Earth-shattering, as far as return on investment to science is concerned, I have my doubts. It depends so much on what's discovered .. which is presently, (officially), 'nothing of bio-significance'. When/if that status changes, it really does come down to the nature of the finding. Until then, its all moot.

Don J
2013-May-13, 03:17 AM
Originally Posted by Don J
Why the need of sending a human mission to Mars?
Lets suppose that the Viking LR positive life detection results is backed by a positive detection of organic matter by Curiosity,
a robotic mission to collect sample(s) and return mission of Martian soil sample(s) to be examined on Earth by biologists whatever it came from one of the Viking landing site or from a Curiosity location, is far more easy and less costly.The only way that a human mission is needed is if they determine that there may be a risk of contamination of Earth with Martian living microbes.



Yeah ... maybe. Levin (for eg) isn't even proposing going that far, either eh?
(Ie: bio-sampling 'dart' drops, etc).

However, such robotic mission to collect and return a sample of Martian soil to Earth is planned by Nasa but this event will probably happen decades in the future.That is why Levin say that if organic matter is detected by Curiosity combined with the LR Viking positive results that we will not have to wait so long for the confirmation that there is living microorganisms in the Martian soil.
See Introduction chapter Pdf
http://www.gillevin.com/Mars/SPIE_2012_As_Accepted_8-27-12.pdf

Selfsim
2013-May-13, 07:26 AM
However, such robotic mission to collect and return a sample of Martian soil to Earth is planned by Nasa but this event will probably happen decades in the future.That is why Levin say that if organic matter is detected by Curiosity combined with the LR Viking positive results that we will not have to wait so long for the confirmation that there is living microorganisms in the Martian soil.
See Introduction chapter Pdf
http://www.gillevin.com/Mars/SPIE_2012_As_Accepted_8-27-12.pdfWell once again if he wants to declare life, then I'd like to know what sort of organics is sufficient for combining with the LR results, in order to declare the presence of life?

So far, SAM has analysed samples from Rocknest and John Klein (4 samples) and is now (?) targetting Cumberland. Chemcam has been fired >~50 times.
The main compounds/elements detected so far are: H2O, CO2, O2, SO2, H2S, H2, CH2Cl2 and CH3Cl. This suggests the presence of perchlorates, carbonates, sulfates and sulfides (clays mainly).

No 'organics' though.

We now know that the sites/samples tested so far, are 'organics' free. Given that the surface gets blown around by martian winds, that may well be what we continue to see everywhere. No 'organics' so far, is not what I'd say is a particularly good sign for Levin's hopes. We shall see, I suppose.
I really think some seriously complex organics would be needed to support LR's apparent metabolism results.

neilzero
2013-May-13, 07:57 AM
The hazard to Earth's population is not zero if we do a sample return, but likely close to zero. Life on Mars results are likely to continue to be uncertain, so perhaps we should concentrate on how a Mars colony of humans can get most of what they need, and want from the surface of Mars. Why not send some robotic factories, and see what they can produce and of what quality?
We don't want to make fuel on Mars for the return trip if a robotic factory can't make a significant amount of quality fuel from local material. Neil

Don J
2013-May-14, 04:16 AM
Well once again if he wants to declare life, then I'd like to know what sort of organics is sufficient for combining with the LR results, in order to declare the presence of life?

Organic carbon...
Probably in the range of Antarctic soil No.726 containing 0.03% organic carbon- which the GCMS was unable to detect from tests done prior the Viking mission.
(In 1979, Biemann reported that organics were undetectable in an Antarctic soil (No. 726) tested by the GCMS prior to launch,but did not say that organics were present in that sample, a significant omission.)-

-Note that the Antarctic soil No.726 provided a LR positive result very similar to the Martian soil sample(s) analysed by the Viking's LR:-
See
Antarctic Soil No. 726 and Implications for the Viking Labeled Release Experiment
http://www.gillevin.com/Mars/Reprint92-scan_images/Reprint92-scan.htm


So far, SAM has analysed samples from Rocknest and John Klein (4 samples) and is now (?) targetting Cumberland. Chemcam has been fired >~50 times.
The main compounds/elements detected so far are: H2O, CO2, O2, SO2, H2S, H2, CH2Cl2 and CH3Cl. This suggests the presence of perchlorates, carbonates, sulfates and sulfides (clays mainly).

No 'organics' though.

The first results are very good, at least for the possibility of ancient microbial life on Mars...
It's official: Primitive life could have lived on ancient Mars, NASA says.
http://www.space.com/20182-ancient-mars-microbes-curiosity-rover.html


CheMin and SAM identified some of the key chemical ingredients for life in this dust, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, researchers said. Intriguingly, the mix also suggested a possible energy source for indigenous Martian life, if any ever existed in the area.

"The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms," Paul Mahaffy, SAM principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement.



We now know that the sites/samples tested so far, are 'organics' free. Given that the surface gets blown around by martian winds, that may well be what we continue to see everywhere. No 'organics' so far, is not what I'd say is a particularly good sign for Levin's hopes. We shall see, I suppose.

The good stuff is expected to be find at
the clay deposits at the base of Mount Sharp — the 3-mile-high (5-kilometer) mountain at the center of Gale
http://www.space.com/16902-mars-rover-curiosity-life-building-blocks.html


The principal investigator for SAM is Paul Mahaffy of the Goddard Spaceflight Center, who has worked to put together the instrument for more than eight years.
He and other NASA scientists are quick to explain that finding organics on Mars will be very hard to do, and that it’s difficult to find organic carbon in rock samples even on Earth. But he sees some real opportunities.

In particular, the clay deposits at the base of Mount Sharp — the 3-mile-high (5-kilometer) mountain at the center of Gale — are especially promising, he said, because clays can trap and preserve organic molecules and compounds.



I really think some seriously complex organics would be needed to support LR's apparent metabolism results.
That is not what was originally needed by the Viking mission to support the Viking LR's metabolism results. A Martian soil sample containing 0.03% organic carbon is probably all it is needed....see Antarctic soil No.726 reference:
Antarctic Soil No. 726 and Implications for the Viking Labeled Release Experiment
http://www.gillevin.com/Mars/Reprint92-scan_images/Reprint92-scan.htm

Selfsim
2013-May-14, 09:35 AM
Organic carbon...
Probably in the range of Antarctic soil No.726 containing 0.03% organic carbon- which the GCMS was unable to detect from tests done prior the Viking mission.
(In 1979, Biemann reported that organics were undetectable in an Antarctic soil (No. 726) tested by the GCMS prior to launch,but did not say that organics were present in that sample, a significant omission.)-

-Note that the Antarctic soil No.726 provided a LR positive result very similar to the Martian soil sample(s) analysed by the Viking's LR:-
See
Antarctic Soil No. 726 and Implications for the Viking Labeled Release Experiment
http://www.gillevin.com/Mars/Reprint92-scan_images/Reprint92-scan.htm
Perhaps ... but until something worthy of the title 'organics' shows up on Mars (meaning, at an absolute minimum: complex carbon bound as sugars, amino acids, lipids, etc .. or even more complex compounds) ... it doesn't really matter what happened with the No. 726 sample ... does it?
(Its just an Earth based analogue ...)

The first results are very good, at least for the possibility of ancient microbial life on Mars...
It's official: Primitive life could have lived on ancient Mars, NASA says.
http://www.space.com/20182-ancient-mars-microbes-curiosity-rover.html
The only thing 'official' about this ... is that its 'official speculation'.
Ie valueless, as far as empirical science is concerned.


The good stuff is expected to be find at
the clay deposits at the base of Mount Sharp — the 3-mile-high (5-kilometer) mountain at the center of Gale
http://www.space.com/16902-mars-rover-curiosity-life-building-blocks.html
Yep .. bring it on!


That is not what was originally needed by the Viking mission to support the Viking LR's metabolism results. A Martian soil sample containing 0.03% organic carbon is probably all it is needed....see Antarctic soil No.726 reference:
Antarctic Soil No. 726 and Implications for the Viking Labeled Release Experiment
http://www.gillevin.com/Mars/Reprint92-scan_images/Reprint92-scan.htmThe proportion by mass is one thing (to confirm the Viking GCMS (relative) insensitivity) .. but the composition and complexity of the organics is all important.

Also, on Earth, it would be extremely rare to find a clay which contains no organics of biological origin ... but on Mars, it may well be the opposite, and be the dominant feature. Who knows? We shall see, eh? (More data needed).

ASTRO BOY
2013-May-14, 10:49 AM
The only thing 'official' about this ... is that its 'official speculation'.
Ie valueless, as far as empirical science is concerned.



Valueless?????
I certainly don't see it as valueless. And I'm sure most scientists, cosmologists and Astrophysicist would not see it as valueless either.
It's genuine logical speculation based on what data we have so far.
Just as the years of speculation of water ice on Mars was finally confirmed with Phoenix.
The speculation of course arose from other less conclusive data, that pointed to that eventual finding.
We have never seen BH's or DM as yet but mainstream science sees plenty of validity and reasons for the assumptions that are made.

Don J
2013-May-14, 06:32 PM
Space.com article:
It's official: Primitive life could have lived on ancient Mars, NASA says.
A sample of Mars drilled from a rock by NASA's Curiosity rover and then studied by onboard instruments "shows ancient Mars could have supported living microbes,

The only thing 'official' about this ... is that its 'official speculation'.
Ie valueless, as far as empirical science is concerned.

It is more than a speculation but an affirmation that Mars could have supported a habitable environment...
http://www.space.com/20182-ancient-mars-microbes-curiosity-rover.html


"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington. "From what we know now, the answer is yes."

Which is backed by


CheMin and SAM identified some of the key chemical ingredients for life in this dust, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, researchers said. Intriguingly, the mix also suggested a possible energy source for indigenous Martian life, if any ever existed in the area.

"The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,"

The fine-grained John Klein rock also contains clay minerals, suggesting a long-ago aqueous environment — perhaps a lake — that was neutral and not too salty, researchers said.

"We have found a habitable environment that is so benign and supportive of life that probably — if this water was around and you had been on the planet, you would have been able to drink it," said Curiosity chief scientist John Grotzinger, of Caltech in Pasadena.



Yep .. bring it on!

Perhaps ... but until something worthy of the title 'organics' shows up on Mars (meaning, at an absolute minimum: complex carbon bound as sugars, amino acids, lipids, etc .. or even more complex compounds) ... it doesn't really matter what happened with the No. 726 sample ... does it?
(Its just an Earth based analogue ...)

The proportion by mass is one thing (to confirm the Viking GCMS (relative) insensitivity) .. but the composition and complexity of the organics is all important.

But as -i have pointed out- what was originally needed for confirming the Viking's LR positive life detection results in Martian soil samples is the discovery of organic carbon.-You definitively seem to have difficulty in accepting the fact that this basic requirement is all that is needed-(?)
Antarctic Soil no.726 at least demonstrated that living microorganisms can live with the level of organic carbon of that sample...which by the way provided a similar LR positive life detection result that the Martian soil sample(s) analysed by the Viking's LR at two different location 4,000 miles apart on the surface of Mars.
http://www.gillevin.com/Mars/Reprint92-scan_images/Reprint92-scan.htm

Selfsim
2013-May-14, 11:42 PM
It is more than a speculation but an affirmation that Mars could have supported a habitable environment...
http://www.space.com/20182-ancient-mars-microbes-curiosity-rover.html

Which is backed by
...
But as -i have pointed out- what was originally needed for confirming the Viking's LR positive life detection results in Martian soil samples is the discovery of organic carbon.-You definitively seem to have difficulty in accepting the fact that this basic requirement is all that is needed-(?).. And you seem to think that its compulsory to accept that the confirmation of what we presently model as a 'habitable environment', necessarily implies the existence of life (in the past or present). It most certainly doesn't, as there is no non-terrestrially sourced data to support this conclusion.

Equally, the reason we call organic carbon, 'organic' on Earth, is because we have abundant evidence (from Earth's case), that biological processes are capable of producing it. This does not mean that biology is necessary for producing complex chain carbon based molecules, for which we have no other classification term other than the all encompassing term, 'organic'.

For example, LH amino acids are known to exist on comets, and thus demonstrates that non-terrrestrial processes are capable of producing biologically significant organic molecules. Does this mean that we can go ahead and declare life on Comet Wild 2 (following an LR test on a sample of it?) If so, then why hasn't this occurred already?

Answer => Because 'organic' molecules displaying 'metabolic-like' responses to an LR test, may not be sufficient cause for classifying them as pertaining necessarily to life.

This fixated idea that life is just some kind of 'shake and bake' chemistry, widely distributed throughout the universe wherever a 'habitable' environment exists and therefore 'allows' for its existence, seems to be what causes many, many diagnostic steps to be skipped over and largely trivialised by overly 'optimistic' amateur exo-life enthusiasts(?) 'Nanobacteria' required ~30 or so lab based tests, before the samples returned a negative life result! Why do you think it took so many tests .. and do you accept the end result of that barrage of empirical evidence?


Antarctic Soil no.726 at least demonstrated that living microorganisms can live with the level of organic carbon of that sample...which by the way provided a similar LR positive life detection result that the Martian soil sample(s) analysed by the Viking's LR at two different location 4,000 miles apart on the surface of Mars.
http://www.gillevin.com/Mars/Reprint92-scan_images/Reprint92-scan.htmLR was testing for a process which occurs on Earth, which is associated with biology - which is called called 'metabolism'. There was a question about whether or not soil 'chemistry' could have produced these same results on the martian tests carried out by Viking. The control samples did not produce the active evolved gases, so the working assumption that the positive LR result was not caused by a known 'chemical reaction' was adopted by some. This does not rule out that there may be active complex reactions and complex carbon based 'organic' compounds in the soil on Mars under ambient conditions there, which are, so far, unknown to be produced by non-biological sources. Levin even proposes that this possibility still exists (albeit with sarcasm).

Soil No 726 contained biological detritus and living organisms .. because that's what creates the overwhelming majority (by mass) of organics on Earth. This does not mean this is how Mars does it.

One might invoke the philosophically based principle of Occams Razor, if one is forced into a corner .. but no-one I can see, (except Levin), is currently in that position. Empirical testing is about evidence. Invoking such philosophical concepts is meaningless in that paradigm.

My bottom line is, as stated many times .. wait for the results of Curiosity's testing. What it does find, will determine the next steps .. and not some hopeful expectations.

Don J
2013-May-15, 02:03 AM
.. And you seem to think that its compulsory to accept that the confirmation of what we presently model as a 'habitable environment', necessarily implies the existence of life (in the past or present). It most certainly doesn't, as there is no non-terrestrially sourced data to support this conclusion.

Equally, the reason we call organic carbon, 'organic' on Earth, is because we have abundant evidence (from Earth's case), that biological processes are capable of producing it. This does not mean that biology is necessary for producing complex chain carbon based molecules, for which we have no other classification term other than the all encompassing term, 'organic'.

For example, LH amino acids are known to exist on comets, and thus demonstrates that non-terrrestrial processes are capable of producing biologically significant organic molecules.
.........
-Antarctic- Soil No 726 contained biological detritus and living organisms .. because that's what creates the overwhelming majority (by mass) of organics on Earth. This does not mean this is how Mars does it.


That is a well know fact that before life was able to develop on Earth that organic matter compounds and some other complex molecules were brought to Earth by Meteorites,interplanetary dust particles and comets.Thus the same for Mars which we know have abondant liquid water on its surface in the past.
You may enjoy this paper which explain that organic compounds are natural by-products of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.
http://www.astrochem.org/docs/Ciesla%202012-Disk%20Irradiation-Science.pdf
Source
http://www.astrochem.org/pub.php#2012


Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments to which they were exposed. We found that icy grains originating in the outer disk, where temperatures were less than 30 kelvin, experienced ultraviolet irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural by-products of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.



For example, LH amino acids are known to exist on comets, and thus demonstrates that non-terrrestrial processes are capable of producing biologically significant organic molecules.
Does this mean that we can go ahead and declare life on Comet Wild 2 (following an LR test on a sample of it?) If so, then why hasn't this occurred already?

Answer => Because 'organic' molecules displaying 'metabolic-like' responses to an LR test, may not be sufficient cause for classifying them as pertaining necessarily to life.

That is not the organic matter which produced the LR positive results but the living microorganisms present in the samples as demonstrated by all the samples tested from Earth samples prior the Viking mission.


This fixated idea that life is just some kind of 'shake and bake' chemistry, widely distributed throughout the universe wherever a 'habitable' environment exists and therefore 'allows' for its existence, seems to be what causes many, many diagnostic steps to be skipped over and largely trivialised by overly 'optimistic' amateur exo-life enthusiasts(?)

Professional biologists are all in agreement that a friendly planet environment containing all the elements necessary for the development of life is needed and the very good example they have for that conclusion is our good old Earth.


'Nanobacteria' required ~30 or so lab based tests, before the samples returned a negative life result! Why do you think it took so many tests .. and do you accept the end result of that barrage of empirical evidence?
You know what ,i am pretty sure that a LR test would have demonstrated that 'Nanobacteria' are not living things.


LR was testing for a process which occurs on Earth, which is associated with biology - which is called called 'metabolism'. There was a question about whether or not soil 'chemistry' could have produced these same results on the martian tests carried out by Viking. The control samples did not produce the active evolved gases, so the working assumption that the positive LR result was not caused by a known 'chemical reaction' was adopted by some. This does not rule out that there may be active complex reactions and complex carbon based 'organic' compounds in the soil on Mars under ambient conditions there, which are, so far, unknown to be produced by non-biological sources. Levin even proposes that this possibility still exists (albeit with sarcasm).
Read this,
Levin with a team of other scientists have personnaly tested the non-biological theory put forward to explain the positive LR results and that does not provide the Viking LR datas.
http://www.gillevin.com/Mars/1993_Tesla_Society_files/1993_tesla_society.htm




My bottom line is, as stated many times .. wait for the results of Curiosity's testing. What it does find, will determine the next steps ..

I agree...


and not some hopeful expectations.

Next steps will be based on expectations too, because NASA chosed to not carry life detection experiment since the Viking mission.It seem that keeping the ambiguity about past or present life on Mars is what drive all the missions on Mars since.
Demonstration:
http://www.space.com/20182-ancient-mars-microbes-curiosity-rover.html


A sample of Mars drilled from a rock by NASA's Curiosity rover and then studied by onboard instruments "shows ancient Mars could have supported living microbes,"

The discovery comes just seven months after Curiosity landed on Mars to spend at least two years determining if the planet could ever have hosted primitive life.

Here the key words:


To be clear, the new find is not evidence that Martian life has ever actually existed; Curiosity carries no life-detection instruments among its scientific gear.

Oops
Another mission will be needed.... still with no life detection instruments on board.
Eta
-See post 1 about Pheonix incapacity to detect organics because it was not equipped with an organic detection instrument for another example of ambiguity driving the need for another mission..-.
http://news.nationalgeographic.com/news/2008/06/080626-mars-lander.html


The MECA team also found that the soil contains magnesium, sodium, potassium, and chloride.

While these are all key nutrients, the tests don't reveal everything needed for life.

For example, the test looked only at inorganic nutrients, not organic compounds, and it didn't look at all of the dozens of potentially important trace nutrients.




Still, said MECA team leader Michael Hecht of NASA's Jet Propulsion Laboratory, "it's a huge step forward."

Yes, thus the need for Curiosity mission....

Selfsim
2013-May-15, 09:31 AM
That is a well know fact that before life was able to develop on Earth that organic matter compounds and some other complex molecules were brought to Earth by Meteorites,cosmic dusts and comets.Thus the same for Mars which we know have abondant liquid water on its surface in the past.
You may enjoy this paper which explain that organic compounds are natural by-products of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.
http://www.astrochem.org/docs/Ciesla%202012-Disk%20Irradiation-Science.pdf
Source
http://www.astrochem.org/pub.php#2012
Thanks .. will have a read when I get the chance .. (I am aware of protoplanetary disk chemistry theory as an explanation for the origin of organics. It does no harm to renew dormant knowledge, too .. :) )



For example, LH amino acids are known to exist on comets, and thus demonstrates that non-terrrestrial processes are capable of producing biologically significant organic molecules.
Does this mean that we can go ahead and declare life on Comet Wild 2 (following an LR test on a sample of it?) If so, then why hasn't this occurred already?

Answer => Because 'organic' molecules displaying 'metabolic-like' responses to an LR test, may not be sufficient cause for classifying them as pertaining necessarily to life.That is not the organic matter which produced the LR positive results ...but the living microorganisms present in the samples as demonstrated by all the samples tested from Earth samples prior the Viking mission.So? That doesn't have to mean that the martian positive LR results were generated by living microorganisms present in the martian soil.
If there were living organisms in the martian sample, then they'd have some amino acid base chemistry, no? If they were non-living, then they'd still exist at various stages of decomposition of DNA, proteins, complex enzymes, amino acids, etc, also(?) Amino acids are clearly able to provide evidence of metabolism, no(?) So why not declare life on Wild 2?

In summary what will be the basis for concluding that living organisms on Mars, produced the LR positive results? Just because that's what caused positive results in sample No. 726?
Mostly, all you have stated so far, is that there was 'likely 'organic carbon' in the reaction chamber. There is 'organic carbon' in amino acids too, no? So, say there were amino acids in the Viking Mars LR sample ... does this mean life is/was present on Mars? If so, then there must also be life on Wild 2(?)


Professional biologists are all in agreement that a friendly planet environment containing all the elements necessary for the development of life is needed and the very good example they have for that conclusion is our good old Earth.All the elements needed for life, are distributed throughout the universe. Does this mean that everywhere those elements aggregate, life will be present? How do you know this?

The statement about: "all the elements necessary for life being present", someplace, is a completely moot point, and is as good as saying nothing new! It carries no new information about the presence of life elsewhere, at all.


You know what ,i am pretty sure that a LR test would have demonstrated that Nanobacteria are not living things.I know for certain that fluorescent microscopy revealed no evidence of DNA in the 'nanobes'. Electron microscopy and gene amplification also returned no evidence of DNA. MALDI-TOF mass spectrometry was also used in confirming this. A lone LR test would have only shown that isotopically marked carbon was absorbed and re-emitted by whatever 'organics' might have been present (below GCMS' sensitivity range) and within its own sensitivity range .. but so what? This says nothing about exactly what 'organic, (apparently) metabolising molecules of interest' were actually present .. nor does it say that these were definitively, 'living' things.


Read this and you will see that that is not sarcasm.He have with a team of other scientist personnaly tested all the non -biological theory put forward to explain the positive results and none of them provide the Viking LR datas.
http://www.gillevin.com/Mars/1993_Tesla_Society_files/1993_tesla_society.htm
So? What about 'organic chemistry which may be present, but is not of biological origins?
The sarcasm I refer to is the declaration of some 'mysterious' chemical reaction (see the Levin quote below). The only 'mystery' may be that some particular scenario of organic chemistry has not yet been contemplated .. and so what? Did anyone envisage perchlorate in martian soil, until it was distinguished by instrumentation?
... that because chemistry on Mars differs from chemistry on Earth, that some mysterious (chemical) reaction, not yet achievable in laboratories, is mimicking life.This would be a difficult case to make before competent chemists and physicists.


Next steps will be based on expectactions too because NASA chosed to not carry life detection experiment since the Viking mission.It seem that keeping the ambiguity about past or present life on Mars is what drive all the missions on Mars since.
Demonstration:
http://www.space.com/20182-ancient-mars-microbes-curiosity-rover.html

Here the key words:


Oops
Another mission will be needed.... still with no life detection instruments on board.
Eta
-See post 1 about Pheonix incapacity to detect organics because it was not equipped with an organic detection instrument for another example of ambiguity driving the need for another mission..-.
http://news.nationalgeographic.com/news/2008/06/080626-mars-lander.html
So ambiguity is deliberate you think? I respect your right to hold that opinion ... (I've found this discussion rather enjoyable) ... and I decline to 'go there' with you (it ain't my kind of thing). (Not that this matters in the overall scheme of things, though .. :) )
At least we agree on: "more data needed"! :)


Yes, thus the need for Curiosity mission...... Which represents the next step in the vital, slow buildup of data, in response to a bewildering array of possible testing equipment and techniques. This is the strategy which will ultimately provide the necessary evidence for an eventual declaration of life, (if it exists there), or 'no life found', (if it isn't found). Without it, there will always be doubt and uncertainty. I really don't think Levin appreciates that this is what it takes. He seems to view his LR test as the ultimate, definitive means for eliminating all possible uncertainties in an alien environment, when it comes to life detection. I do not agree with that view, and I suspect, many others directly currently involved in the hunt for life on Mars, might agree with that(? -IMO)

Don J
2013-May-15, 06:37 PM
So? That doesn't have to mean that the martian positive LR results were generated by living microorganisms present in the martian soil.
If there were living organisms in the martian sample, then they'd have some amino acid base chemistry, no? If they were non-living, then they'd still exist at various stages of decomposition of DNA, proteins, complex enzymes, amino acids, etc, also(?) Amino acids are clearly able to provide evidence of metabolism, no(?) So why not declare life on Wild 2?

In summary what will be the basis for concluding that living organisms on Mars, produced the LR positive results? Just because that's what caused positive results in sample No. 726?

Living microorganisms caused the positive LR results in all the Earth samples tested which was followed by the control tests destined to kill the living microorganisms by poisoning or by heating, all control tests provided negative results after the death of the living microorganisms.The antarctic soil sample no 726 was particularly interesting because it demonstrated the limitation of the GCMS capacity to detect organic matter even in a sample proved to contain living microorganisms.
http://www.gillevin.com/Mars/1993_Tesla_Society_files/1993_tesla_society.htm


The LR Viking Instrument:
Earth Testing - aerobes, anaerobes, chemotrophs, heterotrophs, bacteria, algae, fungi: thousands of tests including pure cultures and soils from many places over the world, field tests in extreme environments. All tests were successful, with no false positives as demonstrated by poisoned or heat-sterilized controls. As few as 10 cells were detected.

ASTRO BOY
2013-May-15, 08:57 PM
Living microorganisms caused the positive LR results in all the Earth samples tested which was followed by the control tests destined to kill the living microorganisms by poisoning or by heating, all control tests provided negative results after the death of the living microorganisms.The antarctic soil sample no 726 was particularly interesting because it demonstrated the limitation of the GCMS capacity to detect organic matter even in a sample proved to contain living microorganisms.
http://www.gillevin.com/Mars/1993_Tesla_Society_files/1993_tesla_society.htm


Obviously we need to seriously get to work on a Martian soil sample return mission as nothing beats hands on expertise...not even our top notch robotic friends.
Such a mission will also give much needed data and experience in getting off Mars in preparation for the inevitable manned return mission.

As long as data and evidence is forthcoming in establishing prime conditions for life either now or in the past, missions in search of samples of or remnants of that possible life should and most certainly will continue, not only to Mars but other places such as Europa and Enceladus where the possible likelyhood of primitive life could exist.
Until we have some positive outcome one way or the other, the lack of certainty makes missions of this type necessary.
Answering with validity and confidence mankind's greatest question would be the great prize that awaits us.

Selfsim
2013-May-15, 09:57 PM
Living microorganisms caused the positive LR results in all the Earth samples tested which was followed by the control tests destined to kill the living microorganisms by poisoning or by heating, all control tests provided negative results after the death of the living microorganisms.The antarctic soil sample no 726 was particularly interesting because it demonstrated the limitation of the GCMS capacity to detect organic matter even in a sample proved to contain living microorganisms.
http://www.gillevin.com/Mars/1993_Tesla_Society_files/1993_tesla_society.htmThis is starting to sound a little repetitive.
Perhaps I could try explaining some background to this.

The LR tests have been designed to detect only one Earth-like life process (Earth-life metabolism) .. and they do that very reliably - acknowledged.

The search for exo-life in science, (not philosophy), is the test for a universal theory of life. Not all exo-life (if it exists) has to necessarily be Earth-like. There may be 'things' out there which emulate some Earth-like life functions, but fail in other respects. For a while, 'nanons' looked like that (they reproduce and intermingle with biology at the molecular levels). At the moment, we cannot predict what might constitute those things. This is one of the motivations in science for the exploration of the unknown - to find those things out. That universal theory of life, and its definitions, are subject to change in the light of extraterrestrial evidence, which eliminates uncertainty.

NASA Astrobiology acknowledges that our definitions of life are, by necessity, purely derived from Earth's instances of life (which all possess common characteristics). This skews and biases subsequent theory, which is in turn, called upon to interpret test results.

The LR test however, pursues a different goal. It is about detecting one purely Earth-like life process. As such, there is other data which must be gathered to constrain the knowledge of exactly what it is, that's being tested (and producing apparent 'metabolism'). On Earth, that's easy. On Mars (Viking), it wasn't (for whatever technical reasons). It doesn't matter how many Earth-life tests LR proved successful in detecting on Earth-life. These cannot exclude a non-terrestrial false positive result. Other data is needed to do this, which is being pursued by Curiosity. The LR control experiment (TV) appears to have 'de-activated' the apparent 'active metabolism' detected in LR. That is all we know.

I actually hope Curiosity identifies some kind of complex bio-organic molecules.
That hope doesn't interfere with the reality of what is actually detected, though.

Selfsim
2013-May-15, 10:19 PM
Obviously we need to seriously get to work on a Martian soil sample return mission as nothing beats hands on expertise...not even our top notch robotic friends.
Such a mission will also give much needed data and experience in getting off Mars in preparation for the inevitable manned return mission.This is part of NASA Astrobiology's published 'Roadmap'.

Precise readings from Curiosity's SAM analysis, I think, will be needed to justify the steps you mention. It will be interesting to see what happens if no complex molecules are detected. The path forward will be more difficult if this happens (unfortunately).


As long as data and evidence is forthcoming in establishing prime conditions for life either now or in the past, missions in search of samples of or remnants of that possible life should and most certainly will continue, not only to Mars but other places such as Europa and Enceladus where the possible likelyhood of primitive life could exist.
Until we have some positive outcome one way or the other, the lack of certainty makes missions of this type necessary.
Answering with validity and confidence mankind's greatest question would be the great prize that awaits us.Somewhat hopeful thinking (IMO).

The 'evidence' will have to be raw data, though (I agree).
Colourful interpretations of that data introduces uncertainty, risk, and a lack of confidence in the overall scientific process.

The days of romantic Saganist musings, may be passe and out of synch with economic realities.

Don J
2013-May-16, 01:28 AM
This is starting to sound a little repetitive.
Perhaps I could try explaining some background to this.

The LR tests have been designed to detect only one Earth-like life process (Earth-life metabolism) .. and they do that very reliably - acknowledged.

The search for exo-life in science, (not philosophy), is the test for a universal theory of life. Not all exo-life (if it exists) has to necessarily be Earth-like. There may be 'things' out there which emulate some Earth-like life functions, but fail in other respects. For a while, 'nanons' looked like that (they reproduce and intermingle with biology at the molecular levels). At the moment, we cannot predict what might constitute those things. This is one of the motivations in science for the exploration of the unknown - to find those things out. That universal theory of life, and its definitions, are subject to change in the light of extraterrestrial evidence, which eliminates uncertainty.

NASA Astrobiology acknowledges that our definitions of life are, by necessity, purely derived from Earth's instances of life (which all possess common characteristics). This skews and biases subsequent theory, which is in turn, called upon to interpret test results.

The LR test however, pursues a different goal. It is about detecting one purely Earth-like life process. As such, there is other data which must be gathered to constrain the knowledge of exactly what it is, that's being tested (and producing apparent 'metabolism'). On Earth, that's easy. On Mars (Viking), it wasn't (for whatever technical reasons). It doesn't matter how many Earth-life tests LR proved successful in detecting on Earth-life. These cannot exclude a non-terrestrial false positive result. Other data is needed to do this, which is being pursued by Curiosity. The LR control experiment (TV) appears to have 'de-activated' the apparent 'active metabolism' detected in LR. That is all we know.

In other words and as i have suspected even if the GCMS would have detected organic matter on Mars this would not have be enough combined with the Viking LR positive results to declare the detection of living microorganisms in the Martian soil, untill a sample of Martian soil -containing living microorganisms- is examined by a microscope....that explain why no other Mars mission was equipped with life detection instruments to verify the first results in the promising Viking's location(s) even after they were in the know that the GCMS was not sensitive enough.That explain also the modus operandi that i point out in post #117.Ambiguity +expectations=another mission....Thanks!

ASTRO BOY
2013-May-16, 01:56 AM
That explain also the modus operandi that i point out in post #117.Ambiguity +expectations=another mission....Thanks!


Bingo!!!

Selfsim
2013-May-16, 07:50 AM
In other words and as i have suspected even if the GCMS would have detected organic matter on Mars this would not have be enough combined with the Viking LR positive results to declare the detection of living microorganisms in the Martian soil, untill a sample of Martian soil -containing living microorganisms- is examined by a microscope….Huh? There's still a major perspective missing here. As I've said before, it depends on exactly what type of 'organic matter' is detected. (I'm talking at the molecular level - long chain complex carbon based 'bio'-molecules). You've assumed that a visible cell would be sufficient. Well nanobes looked like life-structures at microscopic scales, so did ALH 84001. Did a simple microscope resolve any ambiguities in either of these instances? ... Nope!
Evidence of both bio-molecules and cellular structures, along with positive LR results (and negative controls), would probably contribute significantly to the evidence of life, but there's no single 'silver bullet' test known in advance, when you don't know whether the target exists in the first place, or not.

If there had been sufficient organics in the soil, (or GCMS had better sensitivity), then GCMS should have been capable of categorising the molecular carbon present. Curiosity should romp it in on the molecular analysis front (if your speculated micro organisms are/have been homogeneously distributed across the surface there).

The Curiosity MAHLI Hand Lens Imager (http://msl-scicorner.jpl.nasa.gov/Instruments/MAHLI/) has a pixel scale/spatial resolution as high as 13.9 microns per pixel. Most Earth bacterial cells are around 0.2 microns in diameter and ~2 to 8 microns in length. Whilst getting a snapshot of a single cell might be a stretch, most bacterial cells do not exist individually, so MAHLI may be capable of imaging a cluster of them.


… that explain why no other Mars mission was equipped with life detection instrument to verify the first results in the promising Viking's location(s) even after they were in the know that the CGMS was not sensitive enough.SAM, MAHLI and ChemCam, are capable of analysing and categorising the longer chain bio-organics. This data is part of the data needed, in order to contribute towards an ultimate 'life/no life' conclusion in the future. There's lots of other types needed too. The SAM instument alone is quite bulky, and weighs in at 40Kgs. It is largely responsible for Curiosity's size. Viking's LR, PR and GEX instumentation, by comparison was 15.5Kgs (~40% of SAM). Its hard to see how both suites of instruments could have possibly been sent together(?)
Maybe Levin should have concentrated his efforts on miniaturisation of LR ... as opposed to the path he has taken since Viking(?)


That explain also the modus operandi that i point out in post #117.Ambiguity +expectations=another mission....Thanks!Do you really believe there would be no further missions if life was declared?
Surely, you can't be serious?

Frankly IMO, the seeming obsession with finding 'Earth-like life', represents a major risk to ultimately detecting exo-life.
Amateur enthusiasm, involving wild speculation and over-exuberance, feeds directly into that risk.

Selfsim
2013-May-16, 07:54 AM
That explain also the modus operandi that i point out in post #117.Ambiguity +expectations=another mission....Thanks!Bingo!!!You support and applaud a NASA-wide conspiracy theory?
(Wrong forum, methinks!)

ASTRO BOY
2013-May-16, 09:14 AM
You support and applaud a NASA-wide conspiracy theory?
(Wrong forum, methinks!)

There is no conspiracy theory...
Some mistakes and oversights may have occurred....
The data received so far from Mars orbiters and Landers, suggest that life as we know it, could have once existed there and possibily still could....
That inconclusiveness is enough for all possible efforts to continue the search for life rather then the sit on your hands and do nothing approach because of the often mentioned variables of politics and economics.....
And to top it all off, I'm pretty sure that NASA and other similar orginizations will continue the exploration of the solar system and beyond, both robotic and manned, for ETL and yes also just because it's there.

ASTRO BOY
2013-May-16, 09:33 AM
Do you really believe there would be no further missions if life was declared?
Surely, you can't be serious?


Um, not in the least.....
Someone has got their wires crossed somewhere.




Frankly IMO, the seeming obsession with finding 'Earth-like life', represents a major risk to ultimately detecting exo-life.


I don't believe that for one second and am rather bewildered how anyone could reach that conclusion.




Amateur enthusiasm, involving wild speculation and over-exuberance, feeds directly into that risk.


My enthusiasm may be that of an amateur, but as I have said a number of times, that enthusiasm is what I have proudly achieved from reading and listening to many reputable experts involved directly in the field of SETI and the search for ETL and general solar system exploration. Like I said, all reputable and knowledgable people who have made their mark in this discipline.

And of course your take with any speculation being "wild" is way wide of the mark as you well know plus that same reasonable logical speculation is held by the vast majority of space scientists I would suggest.
And it also aligns with the expert supported opinions from the same reputable people I often speak of.

Selfsim
2013-May-16, 11:07 AM
Frankly IMO, the seeming obsession with finding 'Earth-like life', represents a major risk to ultimately detecting exo-life.
Amateur enthusiasm, involving wild speculation and over-exuberance, feeds directly into that risk.Please note: This comment was not intended to be deliberately inflammatory, so do not read it that way. I offer the following evidence in support of my expressed view.

Each of the above mentioned 'responses' was clearly evident from Astrobiological speculative interpretations of the:
- 1976 Viking PR, LR, Gex and GCMS life testing suite results controversy;
- 1996 ALH84001 mars meteorite controversy;
- the 2010 Mono Lake Arsenic DNA controversy and;
- the 1989 to 2008 announcements that nanobacteria, (or 'nanons'), are the agents for all mineral and crystal precipitation, and all oxidation of metals. The subsequent finding being that the morphological structures in question, are in fact, self-propagating mineral-fetuin complexes devoid of DNA.

Each 'controversy' has resulted in varying degrees of damaged reputations, and a loss of public credibility for the scientific process.
(This is the risk I'm alluding to).
Levin also appears to be raising the stakes, setting the expectation that: should organics be found on Mars, then microbial life there can be 'declared' outright.
This is not a view supportable with the current lack of mars-based evidence at hand ... nonetheless, it has been proposed in this thread, and by Levin himself.

One has to ponder whether NASA's 'distancing' itself from outright life detection missions (to Mars in particular, over the years following Viking), might have been in direct response to the risks evoked by the complexities of attempting to remotely distinguish a hypothetical exo-life, of unknown type, of unknown presence, and of unknown whereabouts (if it is present).

Paul Wally
2013-May-16, 02:25 PM
I don't think there is any conspiracy. From looking at the latest Curiosity news conference (in March I think) it is quite clear that there is a sound overall strategy of where Mars exploration is heading. From the beginning it was clear that Curiosity is not a life-detection mission, but rather a search for signs of past habitability. But it's more than just about testing this single hypothesis.

Curiosity is really about geology; it is a field geologist. From the perspective of geology it is then clear where habitability fits into the overall picture. What they're trying to do is to map the geological history of Mars, and this is why the stratified layers of Mt Sharpe is so important. The habitable part will then be located within this overall geological record. So they will be able to see exactly when Mars was habitable, for how long, how the conditions changed during that time, and how it changed from there to be as it is today. I.e. a complete geological record of Mars. This makes sense because if the habitable zone can be located within an exact time period in the geological record of Mars then that will make it easier to plan future missions focused on detecting evidence of life, i.e. they will then know where to look (in a geological sense).

Don J
2013-May-16, 07:04 PM
Do you really believe there would be no further missions if life was declared?
Surely, you can't be serious?

That is not what I said at all.What i said is if all the Viking's instruments for detecting life on Mars have worked properly and that would have provided a strong positive for life...this would have be to early in the exploration of Mars as pointed out by the head biologist of the Viking mission saying "too much to early."Think about it, how much missions would have be needed after a positive result of all the Viking instruments.Probably only one or two missions for a collect sample and return mission for it to be tested on Earth that's all.To resume the hunt for life on Mars (past or present) is more profitable in (number of missions and funding) than finding life at the early stage of Mars exploration...like it would have be the case with Viking .You know the rest of the story about Mars exploration...it was decided to not carry life detection instrument on other Mars missions.... very wise don't you think?
Eta
Note that i am not saying that the GCMS was deliberatery set to not detect the organics in the martian soil sample(s) analysed by the Viking LR instrument.

KABOOM
2013-May-16, 07:22 PM
http://www.theglobeandmail.com/technology/science/canadian-mine-yields-worlds-oldest-free-flowing-water-new-research/article11938571/

Resevoir held under Canadian mines may yield parallels to any underground microbic "life" on Mars.

Selfsim
2013-May-17, 12:00 AM
That is not what I said at all.What i said is if all the Viking's instruments for detecting life on Mars have worked properly and that would have provided a strong positive for life...this would have be to early in the exploration of Mars as pointed out by the head biologist of the Viking mission saying "too much to early."Think about it, how much missions would have be needed after a positive result of all the Viking instruments.Probably only one or two missions for a collect sample and return mission for it to be tested on Earth that's all.To resume the hunt for life on Mars (past or present) is more profitable in (number of missions and funding) than finding life at the early stage of Mars exploration...like it would have be the case with Viking .You know the rest of the story about Mars exploration...it was decided to not carry life detection instrument on other Mars missions.... very wise don't you think?
Eta
Note that i am not saying that the GCMS was deliberatery set to not detect the organics in the martian soil sample(s) analysed by the Viking LR instrument.Thank you for your clarification there, Don J - much appreciated.
Whilst I (now) understand a little more where you're coming from, I find myself querying the speculative premise of the point you make, and make my own point that I personally, do not accept it as a reality:

… if all the Viking's instruments for detecting life on Mars have worked properly and that would have provided a strong positive for life...this would have be to early in the exploration of MarsHaving acknowledged the speculation, it is also appropriate to point out the bald-faced fact is, that Viking did not return this result, (for whatever reasons) and this is the reality left behind by Viking.

.. And as explained, I don't agree that some ~38 years later, (with the benefit of subsequent terrestrial Biological Sciences developments), that the results would now actually constitute a 'strong' a positive result. Note this is speculation, too. The fundamental original test design, was flawed by assumptions made at the time, about the Mars environment, thus allowing for the potential for false results, (positive or negative). These flaws also arose from speculative assumptions made in the equipment design, which was based on Earth-life detection methods and standards. This was to be expected at the time, due to a scarcity of information about the martian environment. These are the key lessons learned from the Viking experience, (as far as remote exo-life detection is concerned), and is my interpretation of "too much, too soon".

So we have historical fact, 'key lessons', and we have a speculative premise.

Even following your speculative 'lead', does not necessarily take me to your conclusion of: "is more profitable in (number of missions and funding) than finding life at the early stage of Mars exploration". The comparison is not valid. Any 'profit' has come from the bulk information returned, (as a result of the subsequent probes). This information is a necessary part, of some future declaration of martian life (if it exists). You are inferring that the information is redundant if Viking's life tests returned an overall positive result (the speculative premise) . I am saying that Viking's returns alone, would not have been sufficient (considering the benefit of ~38 yrs of hindsight), so more missions would have been needed, anyway.

To blindly accept the results of one test (LR), which had never been executed outside of Earth, over all other possible life diagnostic tests, to me, would have been "too much, too early"

You are welcome to your views .. I am not trying to change them. And I decline in accepting them as being the sole explanation for NASA not sending life tests back to Mars.

Acceptance of speculative opinions, is not mandatory in science.

That is my point.

Cheers
PS: For non-participating readers: This discussion is not 'an argument' as far as I'm concerned .. so please refrain from interpreting it that way. It is a conversation of value.

Selfsim
2013-May-17, 07:28 AM
Hmm .. looks like Chris McKay has been rattling his Astrobiology spin sabre again recently ...

Mars Icebreaker Life Mission ... (http://phys.org/news/2013-05-mars-icebreaker-life-mission.html)


... As such, McKay and his colleagues have spent about a decade developing the Icebreaker Life mission to Mars. The spacecraft would drill up to about 3 feet (1 meter) down and scan ice shavings for organic biomarkers—molecules that would be conclusive evidence of life, ones too complex to be produced non-biologically. Discovering any organic biomarkers such as enzymes would not only be evidence of life, but also shed light on the biology of any putative organisms, potentially yielding hints to their genetics and metabolism.... Don't worry 'bout that 'pesky LR old fashioned' experimental stuff, (to actually verify any metabolism present, or anything) ...

A battery of instruments can then analyze this material. For instance, the Signs of Life Detector (SOLID) can detect whole cells, complex organic molecules, and simple compounds of potential biological origin with the aid of a digital camera and the latest generation of lab-on-a-chip technology that essentially shrinks a lab's worth of beakers, flasks and other equipment to fit onto microchips for chemistry experiments.Which would certainly seem to be a much better way to go ... provided 'what ye seek', is actually there ...

Then ...
McKay cautioned Mars might neither have life now nor ever had it in the past. In addition, critics might say "we are advocating the search for organic biomarkers and we do not yet have direct evidence for organics. This is a valid criticism," McKay said. I'll say he needs Curiosity to turn up some of those organics. Which, incidentally it seems he's absolutely convinced himself are there (beyond any shadow of doubt ..).

And then, apparently hedging bets (in case of the mission getting the thumbs down) ..

However, the current government financial crisis might doom the Icebreaker Life mission more than any threats on Mars.
"From a technical point of view, it is perfectly possible," Schorghofer added. "From a budgetary and programmatic point of view, it is unlikely to launch as soon as 2018."... Seemingly no hint of Don J's idea of deliberate prolonging of the agony (for more missions)??

Don J
2013-May-17, 07:17 PM
Hmm .. looks like Chris McKay has been rattling his Astrobiology spin sabre again recently ...

Mars Icebreaker Life Mission ... (http://phys.org/news/2013-05-mars-icebreaker-life-mission.html)


A battery of instruments can then analyze this material. For instance, the Signs of Life Detector (SOLID) can detect whole cells, complex organic molecules, and simple compounds of potential biological origin with the aid of a digital camera and the latest generation of lab-on-a-chip technology that essentially shrinks a lab's worth of beakers, flasks and other equipment to fit onto microchips for chemistry experiments.

... Don't worry 'bout that 'pesky LR old fashioned' experimental stuff, (to actually verify any metabolism present, or anything) ...Which would certainly seem to be a much better way to go ... provided 'what ye seek', is actually there ...

The problem with such fragile electronic equipments is that it is impossible to use the same very high level of sterilization procedure used on Viking without destroying those very fragile electronic components. Thus the samples analyzed can be contamined by Earth spores or living microorganisms which can lead to inconclusive results...-for example the recent incertitude about the origin of carbon detected by Curiosity because the drill have not been adequately cleaned before launch-
See,
Sterilization procedure used on Viking and the problem -even the impossibility -to use the same standard to more recent very fragile electronics life detection instruments.
http://www.nap.edu/openbook.php?record_id=9895&page=17


Don't worry 'bout that 'pesky LR old fashioned' experimental stuff, ...

The LR instrument was not an experimental stuff....as proved by all the thousand of successfull tests.
Here the LR: weigh less than 25 pounds fully equipped Automated Microbial Metabolism Laboratory.
http://www.gillevin.com/Mars/Reprint49_files/Reprint49.htm


Then ...I'll say he needs Curiosity to turn up some of those organics. Which, incidentally it seems he's absolutely convinced himself are there (beyond any shadow of doubt ..).

He have the same certitude that Levin.


And then, apparently hedging bets (in case of the mission getting the thumbs down) ..


However, the current government financial crisis might doom the Icebreaker Life mission more than any threats on Mars.
"From a technical point of view, it is perfectly possible," Schorghofer added. "From a budgetary and programmatic point of view, it is unlikely to launch as soon as 2018."

... Seemingly no hint of Don J's idea of deliberate prolonging of the agony (for more missions)??

That will be the only revert since 38 years after Viking for those making a living from Mars missions 'search for life'....
Note that if organics are find by Curiosity it is possible that the kind of mission that guy propose will not be needed.You can be sure that Levin will be there with his positive life detection results by the Viking LR instrument the only one which will be proved to have worked adequately during the Viking mission

Selfsim
2013-May-18, 02:54 AM
The problem with such fragile electronic equipments is that it is impossible to use the same very high level of sterilization procedure used on Viking without destroying those very fragile electronic components. Thus the samples analyzed can be contamined by Earth spores or living microorganisms which can lead to inconclusive results...-for example the recent incertitude about the origin of carbon detected by Curiosity because the drill have not been adequately cleaned before launch-
See,
Sterilization procedure used on Viking and the problem -even the impossibility -to use the same standard to more recent very fragile electronics life detection instruments.
http://www.nap.edu/openbook.php?record_id=9895&page=17
.. Yeah .. difficult.
Perhaps this is something onsite humans could overcome(??)


The LR instrument was not an experimental stuff....as proved by all the thousand of successfull tests.
Here the LR: weigh less than 25 pounds fully equipped Automated Microbial Metabolism Laboratory.
http://www.gillevin.com/Mars/Reprint49_files/Reprint49.htm
A little miscommunication here .. I didn't mean to imply the experiment itself was in the experimental' stages of development. (Although, clearly, in terms of it not having been tested outside of Earth's environs, its Viking experience represented its first exo-'outing'.. but that wasn't really my point).
It appears to have been superseded by more compact, more diversified 'on-chip' technologies, although, I don't seem to be able to find any specs whatsoever on this "Signs of Life Detector (SOLID)" instrument! There's some material on the physical collection arm, but nothing on the 'smart' back-end part. I've posted threads previously about the single-chip DNA analysis apparatus, but so fa,r I've seen nothing on the integrated SOLID device.

Looks to be a little like a project in need of funding(??)

(The weight quoted for the Viking life analysis lab (25 pounds), is a little shy of the 15.5Kgs (34 pounds) figure I cited from the Lakdawalla article).


He have the same certitude that Levin.I notice he continues to imply that the perchlorates were the reason for GCMS not detecting the assumed organics. This is very much dependent on its concentration vs the concentration of organics though, and surely this will vary from location to location? (Curiosity's, Phoenix's, Viking's etc … they'll all return different concentration results, surely?)

I don't think I've ever heard/seen him saying anything about the GCMS design/sensitivity issue, though(??)


That will be the only revert since 38 years after Viking for those making a living from Mars missions 'search for life'....
Note that if organics are find by Curiosity it is possible that the kind of mission that guy propose will not be needed.Perhaps.
Curiosity can't detect DNA chirality, (for eg). I'm sure there will be other things it can't do, also .. Once again, it all depends on what it is, it finds!
You can be sure that Levin will be there with his positive life detection results by the Viking LR instrument the only one which will be proved to have worked adequately during the Viking missionThe GCMS worked for geological testing ... just not for detecting low concentration TV sensitive organics (which, it seems, it was never specifically intended to do).

Don J
2013-May-18, 04:12 AM
Sterilization procedure used on Viking and the problem -even the impossibility -to use the same standard to more recent very fragile electronics life detection instruments.
http://www.nap.edu/openbook.php?record_id=9895&page=17

.. Yeah .. difficult.
Perhaps this is something onsite humans could overcome(??)

Note that the complete sterilization was achieved with Viking to the point that the Viking LR life detection data are the only data that will ever be available from a PRISTINE Mars. They are priceless, and should be thoroughly studied...citation by Levin .
Good resume related to the present discussion in the phys.org article.
http://phys.org/news/2011-11-curiosity-viking-life-mars.html


The GCMS worked for geological testing ... just not for detecting low concentration TV sensitive organics (which, it seems, it was never specifically intended to do).

Unfortunately.....and also the unknown destructive effects of the perchlorates on the organics when heated at 500 degree Celsius in the oven used by the GCMS....
ETA
An interesting point about sample(s) preservation and contamination issues concern also a possible mission in the futur to return a sample of Mars soil to Earth for detailed study....here the precaution cited by Levin about such a mission which was planned for the year 2001 (uh!)..-planned mission which was obviously cancelled...But the recommandations are still valid.


Amidst all this renewal of the issue of life on Mars, NASA has announced that it will seek the “earliest possible mission, perhaps as early as the year 2001,” to return a sample of Mars soil to Earth for detailed study. I believe this would subject our planet and its life forms to an undue hazard. A more cautious progression might be to send robotic missions to Mars in 1998 to settle the life issue and determine something about any life found. Then any samples for detailed study by human scientists should be returned, not to Earth, but to a laboratory established for the purpose either on the Moon or on the Space Laboratory. In that way the Earth would be protected until we were certain that there was no hazard in returning a sample to Earth.

As early as 1975, Biospherics completed a detailed report under NASA contract entitled “Technology for Return of Planetary Samples.” A major problem in protecting the scientific integrity of the sample was pointed out but has yet to be addressed by NASA. Some means of protecting the sample against changes during the long return trip must be developed. A complex environmental chamber will have to be developed to maintain Martian atmospheric gas pressure and composition, Martian ambient temperature cycling, Martian diurnal lighting, water content in each of the phases occurring on Mars, pH, redox, and other still-undetermined parameters necessary to keep the sample pristine for its examination. AND, to preserve the sample to be able to examine it for living organisms, a whole life-support system must be provided and operated throughout the trip. Otherwise, any microorganisms present would likely use up some vital resource and be seriously impaired or DOA, thereby confusing the whole life issue. The report strongly recommends initial biohazard assessment and the development of suitable control technology. As stated above, the report urges that the sample not be returned directly to Earth, but to an off-Earth laboratory (on the space station)to determine any health or environmental threat.

The famous image returned to Earth from the Apollo Mission shows us how tiny and frail our planet is. We should protect it.

Selfsim
2013-May-18, 06:31 AM
Note that the complete sterilization was achieved with Viking to the point that the Viking LR life detection data are the only data that will ever be available from a PRISTINE Mars. They are priceless, and should be thoroughly studied...citation by Levin .
Good resume related to the present discussion in the phys.org article.
http://phys.org/news/2011-11-curiosity-viking-life-mars.html
Hmm .. more like romantic waxing lyrical Saganist-style stuff, than anything of scientific noteworthiness, methinks.
The 'nutrients' fed to the soil in the LR and GEX experiments, weren't exactly what I'd call 'pristine'!
They were the type of complex organics typically brewed up in a Miller-Urey like cooker ... they called it "chicken soup'!

An interesting point about sample(s) preservation and contamination issues concern also a possible mission in the futur to return a sample of Mars soil to Earth for detailed study....here the precaution cited by Levin about such a mission which was planified for the year 2001 (uh!)..-planned mission which was obviously cancelled...But the recommandations are still valid.Yeah .. I don't buy that a return sample couldn't be contained properly, once it got here.

The famous image returned to Earth from the Apollo Mission shows us how tiny and frail our planet is. We should protect it.... More emotional, overdone cliches ... We've been copping unsterilised rock from mars for billions of years, no?

Most of these concerns sound like a hangover from the 1960s/70s novels/movies .. perhaps "The Andromeda Strain" (http://en.wikipedia.org/wiki/Andromeda_strain)(?)
Its also a way too premature a concern, too ... where is the evidence of any noteworthy organics?
There may be none .. now that would throw a big spanner in all these plans and concerns, eh?

Don J
2013-May-18, 06:40 AM
Yeah .. I don't buy that a return sample couldn't be contained properly, once it got here.

That possibility was effectively in study in 2005...note that New technology is needed for several functions...
Planetary protection technology for Mars Sample Return
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1559390
Abstract


The NASA Mars Exploration Program has recently adopted a plan that includes a first Mars Sample Return (MSR) mission proposed for launch in 2013. Such a mission would deal with two new categories of planetary protection requirements: (1) assuring a very low probability of inadvertent sample release in order to provide extra protection against the extremely unlikely possibility of biological hazards in the returned material; and (2) keeping the samples free of round-trip Earth organisms to facilitate evaluation after return to Earth. This paper describes the planetary-protection-related technical challenges awaiting any MSR mission and describes work in progress on technology needed to meet these challenges. New technology is needed for several functions.

Containment assurance requires breaking the chain of contact with Mars: the exterior of the sample container must not be contaminated with Mars material either during the loading process or during launch from the Mars surface. Also, the sample container and its seals must survive the worst Earth impact corresponding to the candidate mission profile, the Earth return vehicle must provide accurate delivery to the Earth entry corridor, and the Earth entry vehicle must withstand the thermal and structural rigors of Earth atmosphere entry - all with an unprecedented degree of confidence. Sample contamination must be avoided by sterilizing the entire spacecraft, a challenge with modern avionics, or by sterilizing the sample collection and containment gear and then isolating it from other parts of the spacecraft.


. More emotional, overdone cliches ... We've been copping unsterilised rock from mars for billions of years, no?

Because these meteorites from Mars were naturally sterilized by the extreme heat caused by the friction with the Earth atmosphere and i suppose also that the millions/billions of years passed in the harsh cosmic space radiation evironment must be a good sterilization process.

Selfsim
2013-May-18, 07:15 AM
Fobos-Grunt was designed to become the first spacecraft to return a macroscopic sample from an extraterrestrial body (but it didn't make it out of Earth orbit) - I'm not aware of any particularly extraordinary special isolation technologies for that mission(?)

Luna 24 in 1976, and the Apollos returned moon samples - no worries there.

Hayabusa returned microscopic grains of asteroid material in 2010 and Stardust returned cometary dust from Wild 2 in 2006.

No-one seems to have been too worried about any of these samples contaminating Earth!

What makes a Mars return sample so much different from any of these?

Don J
2013-May-18, 07:27 AM
Fobos-Grunt was designed to become the first spacecraft to return a macroscopic sample from an extraterrestrial body (but it didn't make it out of Earth orbit) - I'm not aware of any particularly extraordinary special isolation technologies for that mission(?)

Luna 24 in 1976, and the Apollos returned moon samples - no worries there.

Hayabusa returned microscopic grains of asteroid material in 2010 and Stardust returned cometary dust from Wild 2 in 2006.

No-one seems to have been too worried about any of these samples contaminating Earth!

All these space bodies including the Moon have zero atmosphere and are naturally sterilized by the harsh cosmic space radiation environment. ...


What makes a Mars return sample so much different from any of these?

The answer is simple:
Studies demonstrate that Mars could have supported life in the past and the possibility that living microorganisms have adapted and survived is not zero.

Selfsim
2013-May-18, 08:50 AM
All these space bodies including the Moon have zero atmosphere and are naturally sterilized by the harsh cosmic space radiation environment. ...Funny ... I thought that's why McKay et al are developing an ice drill(?) ... Y'know, because surface organic bio-markers are just about 'sterilised' by Mars' ambient UV, too(?)
I could've sworn I saw a paper somewhere which estimated the depth where lots of organic bio-markers have to 'live' in order to escape the surface UV?
McKay seems to think 3 feet is the go ...

Anyway, presumably the surface of Wild 2 contained Glycine (a biogenic amino acid found in proteins, and an essential component involved in the synthesis of purines (nucleotide bases in our DNA)). So, clearly, the 'sterilising cosmic radiation' didn't do away with that organic bio-marker!

(Man this Astrobiology stuff is ... err .. difficult to pin down)!


The answer is simple:
Studies demonstrate that Mars could have supported life in the past and the possibility that living microorganisms have adapted and survived is not zero.But we already know how to kill them don't we?
... A little heat, a little perchlorate .. and zap!

Don J
2013-May-18, 03:20 PM
Funny ... I thought that's why McKay et al are developing an ice drill(?) ... Y'know, because surface organic bio-markers are just about 'sterilised' by Mars' ambient UV, too(?)
I could've sworn I saw a paper somewhere which estimated the depth where lots of organic bio-markers have to 'live' in order to escape the surface UV?
McKay seems to think 3 feet is the go ...

Other study mention the possibly that one inch below the surface is good enough for UV protection...



Anyway, presumably the surface of Wild 2 contained Glycine (a biogenic amino acid found in proteins, and an essential component involved in the synthesis of purines (nucleotide bases in our DNA)). So, clearly, the 'sterilising cosmic radiation' didn't do away with that organic bio-marker!

No atmosphere on Wild2.The possibility that living microorganisms have developped is zero.Nothing comparable to Mars about the possibility to have supported life in the past and the possibility that microorganisms have adapted and survived in the Martian soil.


But we already know how to kill them don't we?
... A little heat, a little perchlorate .. and zap!

The principle of a sample return mission is for studying a pristine sample...which in the case of Mars may contain living microorganisms.Thus the need for extreme precautions as pointed out in that study.
Planetary protection technology for Mars Sample Return
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1559390

Selfsim
2013-May-19, 06:32 AM
No atmosphere on Wild2.The possibility that living microorganisms have developped is zero.Nothing comparable to Mars about the possibility to have supported life in the past and the possibility that microorganisms have adapted and survived in the Martian soil.Not wanting to divert the thread away form Mars, but by way of comparison, Wild 2 (http://en.wikipedia.org/wiki/Wild_2) is far more consistent with the exo-life paradigm of 'habitability', than Mars appears to be. It has active chemistry including long chain hydrocarbons, a wide range of organic compounds, including two that contain biologically usable nitrogen, gycine aminos, evidence for the presence of liquid water, active outgassing vents, (an atmosphere of sorts?), oxygen isotope signatures, etc.
Interestingly, NASA sent retrieved 81P/Wild particles to about 150 scientists around the globe (upon its return)! Planetary protection protocols? (Evidently not!?!)

So, I ask again .. what makes Mars sample returns so special as to trigger concerns of contamination of Earth's biosphere?


The principle of a sample return mission is for studying a pristine sample...which in the case of Mars may contain living microorganisms.Thus the need for extreme precautions as pointed out in that study.So, from what you appear to be saying, the establishment of planetary protection protocols, is dependent on who thinks which target 'may contain living organisms', eh?

What kind of risk aversion strategy is that?

Colin Robinson
2013-May-19, 07:08 AM
Not wanting to divert the thread away form Mars, but by way of comparison, Wild 2 (http://en.wikipedia.org/wiki/Wild_2) is far more consistent with the exo-life paradigm of 'habitability', than Mars appears to be. It has active chemistry including long chain hydrocarbons, a wide range of organic compounds, including two that contain biologically usable nitrogen, gycine aminos,

Presence of all those compounds, while interesting, is not what I would call "active chemistry". The question is whether the compounds formed billions of years ago, and then remained constant, or are complex organics forming right now? If complex organic molecules are forming right now, or for that matter decomposing right now, that is what I would call "active chemistry".


evidence for the presence of liquid water,

Over what period(s) in the comet's history was water liquid? Has it been liquifying regularly, or has it been in the form of ice for billions of years in the Oort Cloud, until the comet got deflected into the inner solar system and some of the ice then melted?

Selfsim
2013-May-19, 07:32 AM
Presence of all those compounds, while interesting, is not what I would call "active chemistry". The question is whether the compounds formed billions of years ago, and then remained constant, or are complex organics forming right now? If complex organic molecules are forming right now, or for that matter decomposing right now, that is what I would call "active chemistry".
...
Over what period(s) in the comet's history was water liquid? Has it been liquifying regularly, or has it been in the form of ice for billions of years in the Oort Cloud, until the comet got deflected into the inner solar system and some of the ice then melted?We really should start another thread if this topic is of interest ...
The quick and dirty answer however, is that it appears, (from the sample return evidence of 81P/Wild) (http://phys.org/news/2011-04-frozen-comet-watery-scientists.html), that certain collected minerals could have only formed in the presence of liquid water. The current idea is that the heat source creating such liquid, might be from minor collisions with other bodies, (or radioactive decay in the core). If it was the former, then it would suggest that it may be happening all the time, therefore suggesting continuous active chemistry.

Whilst I agree that your questions are good ones Colin, the same questions could also be applied to Mars ... and remain just as unanswered and unknown as in the case of the comet!

Paul Wally
2013-May-19, 12:49 PM
We really should start another thread if this topic is of interest ...
The quick and dirty answer however, is that it appears, (from the sample return evidence of 81P/Wild) (http://phys.org/news/2011-04-frozen-comet-watery-scientists.html), that certain collected minerals could have only formed in the presence of liquid water. The current idea is that the heat source creating such liquid, might be from minor collisions with other bodies, (or radioactive decay in the core). If it was the former, then it would suggest that it may be happening all the time, therefore suggesting continuous active chemistry.

Whilst I agree that your questions are good ones Colin, the same questions could also be applied to Mars ... and remain just as unanswered and unknown as in the case of the comet!

Comets are of great importance to astrobiology, whether there is active chemistry or not. The reason is that ice is a very good preserver of complex organic molecules. So I say, McKay's ice drill could be used on comets, the lunar poles, Mars polar region and then we do comparative studies. Say if certain complex organics are found on Mars, but they are not found in any comets or on the lunar south pole, then we know that they are most probably "home grown" rather than delivered by comets or meteorites.

We now know how the organics are destroyed so it's just a matter of looking in the right places where that mechanism doesn't exist, like beneath the Martian surface, permafrost ice or in the polar ice.

Don J
2013-May-19, 06:28 PM
Not wanting to divert the thread away form Mars, but by way of comparison, Wild 2 (http://en.wikipedia.org/wiki/Wild_2) is far more consistent with the exo-life paradigm of 'habitability', than Mars appears to be. It has active chemistry including long chain hydrocarbons, a wide range of organic compounds, including two that contain biologically usable nitrogen, gycine aminos, evidence for the presence of liquid water, active outgassing vents, (an atmosphere of sorts?), oxygen isotope signatures, etc.
Interestingly, NASA sent retrieved 81P/Wild particles to about 150 scientists around the globe (upon its return)!

Here the explanation about the presence of these complex organic compounds discovered on Wild 2 including how they were produced within the solar nebula


Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments to which they were exposed. We found that icy grains originating in the outer disk, where temperatures were less than 30 kelvin, experienced ultraviolet irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural by-products of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.

in that 2012 paper.
http://www.astrochem.org/docs/Ciesla%202012-Disk%20Irradiation-Science.pdf
Source
http://www.astrochem.org/pub.php#2012



Planetary protection protocols? (Evidently not!?!)

So, I ask again .. what makes Mars sample returns so special as to trigger concerns of contamination of Earth's biosphere?

The description about what they have find on Wild 2 is about non living "tingies".The possibility that there may still exist linving microorganisms on Mars even if not proven, lead to the extreme bio-secutity protocol needed for a Mars sample return.


So, from what you appear to be saying, the establishment of planetary protection protocols, is dependent on who thinks which target 'may contain living organisms', eh?

What kind of risk aversion strategy is that?

The return of a sample which may contain living microorganisms (in Mars soil) versus something containing non living microorganisms is what makes the difference.

Here the kind of cross-contamination who may happen on Mars because the actual Curiosity rover was not cleaned and sterilized according to the protocols....and also the consequences for the Curiosity Mission (terrestrial organics could contaminate soil samples, giving experiments false positives).
"The earth strain"--- have nasa missions contaminated mars.
http://www.dailygalaxy.com/my_weblog/2011/12/the-earth-strain-have-nasa-missions-contaminated-mars.html


Should Earth bacteria make it to the surface of Mars' Gale Crater -landing site of the Mars Curiosity rover (above), terrestrial organics could contaminate soil samples, giving experiments false positives of a second genesis on Mars. Even worse, should there be indigenous life on Mars, any accidental microbes from Earth could destroy microbial alien life.
During the preparation for the launch of NASA's Mars Science Laboratory (MSL) Curiosity on Nov. 26, a step in the "planetary protection" procedure wasn't adhered to. The procedure's key purpose is to make sure organic material from Earth doesn't get transferred accidentally to the Red Planet.

So imagine what are the risks for the Earth about a return Martian soil sample which may contain living microorganisms -if the return capsule is not properly sealed and sterilised-(among other things: see link)...do you want to take the risk.

Planetary protection technology for Mars Sample Return
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1559390

Possible free papers on google:
http://www.google.ca/search?q=Planetary+protection+technology+for+Mars+ Sample+Return&ie=utf-8&oe=utf-8&rls=org.mozilla:en-US:unofficial&client=firefox-a&gbv=1&sei=Mi2ZUaHIErPF4AP4-YCQCQ

Selfsim
2013-May-19, 10:25 PM
… Say if certain complex organics are found on Mars, but they are not found in any comets or on the lunar south pole, then we know that they are most probably "home grown" rather than delivered by comets or meteorites.Nonsense.
In this hypothetical, all we 'know' is that they were found on Mars, and not on the comets sampled, nor were they found in samples tested from the lunar south pole.

The hypothetical is presently inaccurate anyway, as they have been found on a comet (81P), and not on Mars! (Glycine is a complex organic molecule).


We now know how the organics are destroyed so it's just a matter of looking in the right places where that mechanism doesn't exist, like beneath the Martian surface, permafrost ice or in the polar ice.How do we now know that the organics were destroyed?

Are you referring to TV destruction of active chemistry, .. the effects of other sterilising chemistry (eg: perchlorate by-products) … surface UV sterilisation, (hypothesised in Mars' case), or because of some superficial over-simplification of sample results, (coupled together with our arbitrary definitions of comets/asterioids), which somehow now mysteriously excludes the possible presence of complex organics on them?

If no 'complex organics' are found someplace, this does not tell us what destroyed them! 'Complex organics' have been detected floating around in space! Are you saying that whatever "destroyed" them on comets/asteroids, is absent everywhere in a region of space where they have been detected? If this is so, then why isn't the simple absence of 'complex organics', in a given region of space (or comets/asteroids), not just as valid as your hypothetical complex organics-free comets/asteroids?

TooMany
2013-May-19, 10:26 PM
Concerning NASA's motives in not including "life-detection" experiments in explorers since Viking:

Claims of life detection tend to become sensationalized by the press and have resulted in some embarrassments for NASA, such as the Mars rock controversy. Although many experts disagreed that the Mars rock contained evidence of life, the nature of what is seen in that rock is still not fully understood as far as I am aware. Nor is the nature of so-called nanobes found on Earth well understood as yet.

Any indirect evidence currently obtainable for life on Mars will be subject to debate. An enthusiastic endorsement of some finding as evidence of life that turns out not to be 100% definitive invites public and particularly political ridicule.

These are reasons for NASA to take an extremely conservative approach to answering the question "is there life on Mars".

Another problem NASA may face, if they include "life detection" equipment, is that a negative result for surface life could be damaging to the entire Mars exploration program. That is, public or political support might be undermined by a negative finding. A positive finding of life on the surface seems somewhat of a long shot, even if life does exist on Mars. Surface conditions do not appear conducive to life. UV radiation and cosmic rays are largely unfiltered by the thin atmosphere. There is little to no evidence of existing surface water. Also there has been strong evidence of oxidizing compounds (perchlorates). These perchlorates may exist due to UV powered chemical reactions on the surface.

Given all that, I can see why there is not a high priority placed on surface life detection experiments. Yet, it does appear that surface conditions may be quite, well, superficial. Just looking the hole drilled by Curiosity, it appears that the familiar reddish surface is nothing but a thin covering over material with a very different appearance. It is possible that the life-damaging perchlorates exist only in this very thin layer of material and that they are of no consequence under the surface. This surface chemistry added to confusion over the Viking results.

So to me, the conservative course that NASA has chosen is well justified and probably does not reflect any hidden conclusion that life cannot exist on Mars nor that life could not have existed in the past. Studying the geology of Mars will give us more information about the possibility of past life and may provide hints about where we should look for extant or fossil life in future missions.

TooMany
2013-May-19, 10:41 PM
If no 'complex organics' are found someplace, this does not tell us what destroyed them! 'Complex organics' have been detected floating around in space! Are you saying that whatever "destroyed" them on comets/asteroids, is absent everywhere in a region of space where they have been detected? If this is so, then why isn't the simple absence of 'complex organics', in a given region of space (or comets/asteroids), not just as valid as your hypothetical complex organics-free comets/asteroids?

Isn't it rather obvious what might destroy complex organic molecules on the surface of Mars? Constant exposure to UV light will destroy most organics, even fairly robust ones like those used in plastics are destroyed by UV radiation at levels lower than exist on the surface of Mars. Just look at what happens to organic dyes on Earth from light shining through a window (which removes a good chunk of the UV).

Unlike Earth, there are few processes on Mars capable of rapidly exposing intact organic compounds to the surface. Once organics arrive at the surface, they are quickly destroyed. Conditions inside comets are different. We see organics in cometary tails because they are exposed by the melting of volatiles that have protected them from UV rays. The same is true of organics we find in meteors.

Here's a question for you. Why would Earth be so well endowed with organics and not Mars?

Selfsim
2013-May-19, 11:23 PM
Isn't it rather obvious what might destroy complex organic molecules on the surface of Mars? Constant exposure to UV light will destroy most organics, even fairly robust ones like those used in plastics are destroyed by UV radiation at levels lower than exist on the surface of Mars. Just look at what happens to organic dyes on Earth from light shining through a window (which removes a good chunk of the UV). .. A simple UV opaque barrier prevents this from happening … like hiding them behind a rock!
Let me see .. oh yeah .. Viking already did that test ..

Unlike Earth, there are few processes on Mars capable of rapidly exposing intact organic compounds to the surface. Once organics arrive at the surface, they are quickly destroyed. Conditions inside comets are different. We see organics in cometary tails because they are exposed by the melting of volatiles that have protected them from UV rays. The same is true of organics we find in meteors.You mean like what happens each season on the polar regions of Mars?


Here's a question for you. Why would Earth be so well endowed with organics and not Mars?Hmmm .. the presence of extant and past life?

… Notice that how I answer, doesn't have to have anything to do with empirical reality .. (in a speculation forum).

Selfsim
2013-May-19, 11:32 PM
Out of interest in the noble cause of electron conservation, (they're useful for lots of other things y'know), I'll get to where I'm coming from ..

IMO, I don't 'get' that the development of planetary protection measures or (initiatives) is specifically limited to Mars return sample missions. It does seem like a good idea to undertake such measures, in order to eliminate uncertainties which are explainable by terrestrial contamination mechanisms, for any and all sample return missions, though.

So why should a Mars return sample mission be singled out, and lumbered with the exorbitant costs of developing orbiting (or lunar) based labs for the purpose? I find this difficult to accept, given that we still haven't yet found any positively unambiguous evidence of extant complex organics (etc) there anyway?

Its an entirely separate topic, (IMO). Worthy of its own thread, even? ..

Paul Wally
2013-May-20, 02:36 AM
Nonsense.
In this hypothetical, all we 'know' is that they were found on Mars, and not on the comets sampled, nor were they found in samples tested from the lunar south pole.

All I'm saying is that if certain organics are found on Mars which are not found anywhere else we looked (except Earth of course) then they most probably formed on Mars. Of course that will require sampling from a sufficiently large number of locations external to Mars to get something representative.



The hypothetical is presently inaccurate anyway, as they have been found on a comet (81P), and not on Mars! (Glycine is a complex organic molecule).

What is your point. I didn't say complex organic molecules are not found in comets.


How do we now know that the organics were destroyed?

I said we know how they are destroyed. The mechanism for their destruction exists on the surface of Mars currently. So whatever complex organics were delivered to Mars via impacts from comets and meteorites must have been destroyed on the surface, but they might still exist sub-surface or inside polar ice where they are not exposed to the same conditions as on the surface (Perchlorate and UV).


If no 'complex organics' are found someplace, this does not tell us what destroyed them! 'Complex organics' have been detected floating around in space! Are you saying that whatever "destroyed" them on comets/asteroids, is absent everywhere in a region of space where they have been detected? If this is so, then why isn't the simple absence of 'complex organics', in a given region of space (or comets/asteroids), not just as valid as your hypothetical complex organics-free comets/asteroids?

You misread me completely. I never said complex organics are destroyed on comets/meteorites. They are destroyed on the current surface of Mars. That is
the only explanation for why they are not there. Given that Mars have been bombarded with comets and meteorites for billions of years means that complex organics must have been delivered to Mars, and that is why their absence on the surface requires explanation.

Don J
2013-May-20, 03:51 AM
Out of interest in the noble cause of electron conservation, (they're useful for lots of other things y'know), I'll get to where I'm coming from ..

IMO, I don't 'get' that the development of planetary protection measures or (initiatives) is specifically limited to Mars return sample missions. It does seem like a good idea to undertake such measures, in order to eliminate uncertainties which are explainable by terrestrial contamination mechanisms, for any and all sample return missions, though.

Extensive measures are taken for the protection of other celestial bodies against cross-contamination by Earth living microorganisms and terrestrial organic matter as a result of spacecraft missions.
http://www.nap.edu/openbook.php?record_id=9895&page=17
For example this debate about
Preventing the Forward Contamination of Europa
http://www.nap.edu/catalog.php?record_id=9895


So why should a Mars return sample mission be singled out, and lumbered with the exorbitant costs of developing orbiting (or lunar) based labs for the purpose?

We have already a space station the only thing needed will be the construction of a laboratory attached to it.


I find this difficult to accept, given that we still haven't yet found any positively unambiguous evidence of extant complex organics (etc) there anyway?

With all due respect !You definitively seem to have a difficulty to accept the possibilty that there are living microorganisms which may have adapted and survived only few inches below the surface of Mars where they are protected from the UV ...but by chance scientists seem to see a real risk.
The best protection at a real low cost is never return a Mars soil sample(s)to Earth and never send a human mission on Mars.Maybe the risk of contamination is the reason why there is a project for a human mission on Phobos rather than Mars.

Selfsim
2013-May-20, 07:26 AM
All I'm saying is that if certain organics are found on Mars which are not found anywhere else we looked (except Earth of course) then they most probably formed on Mars. Of course that will require sampling from a sufficiently large number of locations external to Mars to get something representative.Which shows that the empirical tests "from a sufficiently large number of locations external to Mars to get something representative" are necessary before this hypothesis carries any weight other than casual interest!

What is your point. I didn't say complex organic molecules are not found in comets.The point was made clear .. the point was that the hypothetical is not even based on a scenario of what is presently known!

I said we know how they are destroyed. The mechanism for their destruction exists on the surface of Mars currently. We don't know how, or whether they were 'destroyed' ... there are many explanations for their apparent absence .. note: not necessarily their 'destruction', either. In this hypothetical, you have taken as reality, that all complex organics were in fact, "delivered to Mars via impacts from comets and meteorites" and then destroyed by seemingly one mechanism (UV/perchlorate activity)? Is this interpretation correct?

So whatever complex organics were delivered to Mars via impacts from comets and meteorites must have been destroyed on the surface, but they might still exist sub-surface or inside polar ice where they are not exposed to the same conditions as on the surface (Perchlorate and UV). Are you stating this "must" as fact, or is it part of your now, embellished-with-assumptions, speculative hypothesis?
Who says specific complex organic-bearing comets/meteorites delivered their 'payloads' to the polar regions? How did the delivered organics get underground, without being altered into something else in the process? What effect did the impact event have on them? Did it alter their composition prior to Mars' extant environmental influences? Did the impact event also alter Mars' extant environmental conditions? Why doesn't their encapsulation in polar ice also alter their (hypothetically) originally 'delivered' composition?

You misread me completely. I never said complex organics are destroyed on comets/meteorites. They are destroyed on the current surface of Mars. That is the only explanation for why they are not there.It is not the "only" explanation for their presently apparent absence. Comets (& meteorites) also endure exposure to sterilising surface radiation. So far this, (and admittedly perchlorate presence), is the only mechanism you have cited, which also effects the surface of comets (not sure about the perchlorates, though .. I'm sure we can find some alternative cometary oxidant to take its place, though).
Oh, and also, Levin has yet another explanation for the apparent "absence" of organics. Have you considered this in your exclusion of all other "possibilities" (reference: "must", in your above 'hypothetical' (which now appears to have morphed into reality))? If so, why?
Given that Mars have been bombarded with comets and meteorites for billions of years means that complex organics must have been delivered to Mars, and that is why their absence on the surface requires explanation.An explanation which will mean very little without more data from Mars.

Demands for 'explanations', cannot generate physical reality in the absence of sufficient, unambiguous onsite data ... which is presently, vastly incomplete, to the extent that empirical reality cannot yet be established, (regardless of speculative hypotheticals).

Selfsim
2013-May-20, 08:25 AM
Extensive measures are taken for the protection of other celestial bodies against cross-contamination by Earth living microorganisms and terrestrial organic matter as a result of spacecraft missions.
http://www.nap.edu/openbook.php?record_id=9895&page=17
For example this debate about
Preventing the Forward Contamination of Europa
http://www.nap.edu/catalog.php?record_id=9895
Yep .. I'm aware of this .. (they also slip-up from time to time). :)

The 'forward' contamination issue is more about eliminating measurement uncertainties. (Enter the panspermists)

The 'backwards' contamination issue however, is common to all sample returns .. not just planetary, (or even Martian only sample returns).

We have already a space station the only thing needed will be the construction of a laboratory attached to it.Yep .. point taken. Does the ISS have the necessary equipment to carry out any more in-depth sample analysis than say, an onsite Curiosity-style lab?
If not, then how much additional cost would that contribute to a Mars sample return mission, I wonder? Any ideas?

With all due respect! You definitively seem to have a difficulty to accept the possibilty that there are living microorganisms which may have adapted and survived only few inches below the surface of Mars where they are protected from the UV ...I have no difficulties in doing this.
'Accepting the possibility' is irrelevant.


but by chance scientists seem to see a real risk.Scientists have irrelevant opinions too y'know .. they're human.
Oh ... yeah ..and a small number are actually empowered, in varying degrees, to propose and design experiments for testing properly formed scientific hypotheses, too.

The best protection at a real low cost is never return a Mars soil sample(s)to Earth and never send a human mission on Mars.Maybe the risk of contamination is the reason why there is a project for a human mission on Phobos rather than Mars.On what empirical basis is the risk mitigated by doing a sample reurn from Phobos? Is Phobos 'immune' from Martian micro-organisms? How do we know this?

Don J
2013-May-20, 07:09 PM
.. A simple UV opaque barrier prevents this from happening … like hiding them behind a rock!
Let me see .. oh yeah .. Viking already did that test ..

The reason they have returned a rock to take a soil sample under it was to verified the early hypothesis put forward during the Viking mission that the LR positive results was caused by a chemical reaction with an oxidant that the UV action may have formed on the Martian surface.The fact that the LR have provided a positive result also with a sample of soil taken under a rock have demonstrated that the LR positive results was not caused by an oxidative chemical reactions.

-To resume the perchlorate which is an oxidant is not the cause of the LR positive results but is the cause for the GCMS not detecting the organics compounds in the samples.
-Then
because perchlorate(when heated in the GCMS oven at 200 celsius degree+) would have broken down any Martian organics , the question of whether or not Viking found organic compounds is still wide open. -
http://en.wikipedia.org/wiki/Viking_spacecraft_biological_experiments#Controver sy


Organic compounds seem to be common, for example, on asteroids, meteorites, comets and the icy bodies orbiting the Sun, so detecting no trace of any organic compound on the surface of Mars came as a surprise. The GC-MS was definitely working, because the controls were effective and it was able to detect traces of the cleaning solvents that had been used to sterilize it prior to launch.[9] At the time, the total absence of organic material on the surface made the results of the biology experiments moot, since metabolism involving organic compounds were what those experiments were designed to detect. However, the general scientific community surmise that the Viking's biological tests remain inconclusive.[1][10][11][12] Most researchers surmise that the results of the Viking biology experiments can be explained by purely chemical processes that do not require the presence of life, and the GC-MS results rule out life.

Despite the positive result from the Labeled Release experiment, a general assessment is that the results seen in the four experiments are best explained by oxidative chemical reactions with the Martian soil. One of the current conclusions is that the Martian soil, being continuously exposed to UV light from the Sun (Mars has no protective ozone layer), has built up a thin layer of a very strong oxidant. A sufficiently strong oxidizing molecule would react with the added water to produce oxygen and hydrogen, and with the nutrients to produce carbon dioxide (CO2).

On August 2008, the Phoenix lander detected perchlorate, a strong oxidizer when heated above 200°C. This was initially thought to be the cause of a false positive LR result.[13][14] However, results of experiments published in December 2010[15][16][17] propose that organic compounds "could have been present" in the soil analyzed by both Viking 1 and 2, since NASA's Phoenix lander in 2008 detected perchlorate, which can break down organic compounds. The study's authors found that perchlorate can destroy organics when heated and produce chloromethane and dichloromethane as byproduct, the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars. Because perchlorate (when heated in the oven at 200 celsius degree+)would have broken down any Martian organics, the question of whether or not Viking found organic compounds is still wide open.[18][19]

Don J
2013-May-20, 07:28 PM
The 'backwards' contamination issue however, is common to all sample returns .. not just planetary, (or even Martian only sample returns).

I have no difficulties in doing this.
'Accepting the possibility' is irrelevant.

Scientists have irrelevant opinions too y'know .. they're human.
Oh ... yeah ..and a small number are actually empowered, in varying degrees, to propose and design experiments for testing properly formed scientific hypotheses, too.

The absence of 100 percent certitude that there is no danger of contamination from a Martian soil sample return is enough.


On what empirical basis is the risk mitigated by doing a sample reurn from Phobos? Is Phobos 'immune' from Martian micro-organisms? How do we know this?
Phobos is as sterile than our Moon that must be good as empirical basis.

Selfsim
2013-May-20, 10:05 PM
The reason they have returned a rock to take a soil sample under it was to verified the early hypothesis put forward during the Viking mission that the LR positive results was caused by a chemical reaction with an oxidant that the UV action may have formed on the Martian surface.No.
A second sample was taken from a different environment for comparison of results with the first sample. 'Seemingly' one shielded almost entirely from UV, 'probably' for eons.
From a subsequent comparison of LR test results between the two samples, the major characteristics were found to be similar.
Assuming the sample contents (chemicals) to be 'approximately similar', apparently the presence of long term exposure to UV, did not significantly alter the LR results.

(One point here is that empirical testing deliberately avoids setting out to verify a hypotheses. To deliberately do so is pure pseudoscience. The usual posture taken, is one which allows for the results to actually falsify the hypothesis under test. Seeking verification (only) automatically rules this out, which is why this isn't the objective).


The fact that the LR have provided a positive result also with a sample of soil taken under a rock have demonstrated that the LR positive results was not caused by an oxidative chemical reactions.Well, one might also point out that evidently, under the hypothesis that the sample contains 'metabolising micro-organisms', the apparent metabolism displayed by these hypothetical micro-organisms, appears to be largely uneffected by long term exposure to martian UV.

This would be one interpretation only, also. There are others which have not been eliminated. GCMS producing more sensitively precise results by adopting different test techniques (like low temperature wet chemistries), would have made a big difference. There may be other reactions not considered so far, which could also account for an LR positive result. These are presently only eliminated by what is currently known or hypothesised from terrestrial experience. Mars is not a terrestrial experience. Uncovering what these 'unknowns' might be, is the overall scientific purpose behind exploration of Mars.


-To resume the perchlorate which is an oxidant is not the cause of the LR positive results but is the cause for the GCMS not detecting the organics compounds in the samples.The release of chloromethane and dichloromethane required the presence of other organics in the reaction chamber. So far, exactly what those organics were, where they originated, and why they evolved the labelled gases, is not yet known.

The cause of the positive LR results, is thus also not yet known.

-Then
because perchlorate(when heated in the GCMS oven at 200 celsius degree+) would have broken down any Martian organics , the question of whether or not Viking found organic compounds is still wide open. -
http://en.wikipedia.org/wiki/Viking_spacecraft_biological_experiments#Controver syI agree that: "whether or not Viking found organic compounds is still wide open".
:)

Selfsim
2013-May-20, 10:14 PM
The absence of 100 percent certitude that there is no danger of contamination from a Martian soil sample return is enough.A matter of risk assessment, and of subsequent evidence based judgment.


Phobos is as sterile than our Moon that must be good as empirical basis.(i)References?
(ii) How do we know Phobos is 'sterile', (seeing as you've stated it as empirical fact .. which differs significantly from speculation)?

Selfsim
2013-May-20, 11:35 PM
Just sharing some reflective thoughts here, (so please excuse the slight diversion .. 'twill only be a one-post 'behind the scenes explanation of my thoughts/motivations) ...

For me, the conversations with Paul Wally, TooMany and now Don J, (the Phobos analogy), all have one major aspect in common .. they all draw upon examples of astronomical objects grouped together under common features (ie: planets, moons and comets). Whilst these objects obviously do have certain features in common, they have also ended up exhibiting dramatically different features in spite of those common features, as well. The outwardly visible (macro) effects of the presence of evolved life, is one of them. The causes of apparent metabolism, (in response to Levin's LR tests on Mars), may also be another of them - we don't yet know.

The arguments put forward by Paul, TooMany and Don J, all draw upon the macro astronomical features in common, and attempt to draw inference from these to make definitive statements about the 'likelihood' of life increasing (usually by arguing the connections between the environment, which is known to constrain, (within certain limits), the Evolution of life on Earth).

This however, completely ignores the equally valid dissimilarity aspects amongst the planets, moons, comets and asteroids which populate our Solar System. Why do we choose to infer from only the physical similarities and not the dissimilarities? Surely this results in a bias and an imbalance, when considering the total evidence at hand?

We might have cleverly developed physical explanations for similarities and dissimilarities which provide the quite sound basis of empirically based Physics principles in order to guide research .. but exploration of another planet has to be about testing inferences derived from those explanations, to see if such inferences are in fact, valid (they may not be). If we allow those inferences to drive the interpretation of the results, we are no longer testing those inferences. We are attempting to prove them right .. which is a philosophically based objective, usually regarded as exclusive from Empirical Science(?)

Don J
2013-May-21, 12:22 AM
Originally Posted by Don J View Post
The reason they have returned a rock to take a soil sample under it was to verified the early hypothesis put forward during the Viking mission that the LR positive results was caused by a chemical reaction with an oxidant that the UV action may have formed on the Martian surface


No.
A second sample was taken from a different environment for comparison of results with the first sample. 'Seemingly' one shielded almost entirely from UV, 'probably' for eons.
From a subsequent comparison of LR test results between the two samples, the major characteristics were found to be similar.
Assuming the sample contents (chemicals) to be 'approximately similar', apparently the presence of long term exposure to UV, did not significantly alter the LR results.

Right for the LR results, but in your reply to Too Many in post 152 the subject in litige was about the destruction of complex organic molecule at the surface of Mars by the UV.The LR test was about metabolism....The soil sample taken on the surface and the sample taken in the soil under the rock protected from the UV and from the surface oxidant provided similar LR positive metabolism results. Thus proving that the LR positive results was not caused by a oxidative chemical reactions.
See page 5 of the PDF (post 1)
http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf
"After the first LR positive result....
Some astrobiologists immediately suggested that the Martian soil was "activated" by the UV light hitting it.We quickly eliminated that theory by moving a rock at dawn and testing the soil underneath.It was fully active."

Selfsim
2013-May-21, 02:12 AM
Right for the LR results, but in your reply to Too Many in post 152 the subject in litige was about the destruction of complex organic molecule at the surface of Mars by the UV.The LR test was about metabolism....The soil sample taken on the surface and the sample taken in the soil under the rock protected from the UV and from the surface oxidant provided similar LR positive metabolism results. Thus proving that the LR positive results was not caused by a oxidative chemical reactions. .. and thus also showing that the 'apparent metabolism' displayed by the unshielded sample, was uneffected by eons of exposure to UV at the surface … which would be an unexpected result, if the sample contained Earth-like, (complex organic molecular) based microbiology ...

Apparently, it wasn't UV which killed off the 'apparent metabolism'.
The current hypothesis is that the 'deactivation' was achieved courtesy of chloromethane/dichloromethane by-products, produced during the heating in the reaction chamber combined with the interaction of organics and perchlorate (with perchlorate being confirmed to be present within the vicinity of Phoenix, to the north, and now Curiosity (to the East?)

See page 5 of the PDF (post 1)
http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf
"After the first LR positive result....
Some astrobiologists immediately suggested that the Martian soil was "activated" by the UV light hitting it.We quickly eliminated that theory by moving a rock at dawn and testing the soil underneath.It was fully active."Just because Levin is using the results to make his point, doesn't mean it doesn't also show other things ...

Paul Wally
2013-May-21, 02:33 AM
Which shows that the empirical tests "from a sufficiently large number of locations external to Mars to get something representative" are necessary before this hypothesis carries any weight other than casual interest!


Yeah, the weight comes after the idea is put to the test. But without the idea there is nothing to test.


The point was made clear .. the point was that the hypothetical is not even based on a scenario of what is presently known!

What is presently known? I'm more interested in discussing possible ways of knowing more in the future. One proposal is that we humans should investigate the different water ices on the Moon, Mars, comets, and now Mercury and compare their organic contents. There will certainly be something important to learn from that.



We don't know how, or whether they were 'destroyed' ... there are many explanations for their apparent absence .. note: not necessarily their 'destruction', either. In this hypothetical, you have taken as reality, that all complex organics were in fact, "delivered to Mars via impacts from comets and meteorites" and then destroyed by seemingly one mechanism (UV/perchlorate activity)? Is this interpretation correct?

Yes some organics and water are delivered by comets and meteorites, also by micro meteorites. These are some of the ways water and organics gets onto a planetary body. This seems to be generally the way the solar system works. They've even discovered ice with what looks like concentrations of complex organics on Mercury's poles.

It is becoming more clear now that the Martian surface environment is, as they say, "hostile" to organic molecules. If Curiosity could just find something solid with carbon atoms in it, I'll be very happy. But as things stand now the only significant amount of carbon we know about is in the atmosphere.


Who says specific complex organic-bearing comets/meteorites delivered their 'payloads' to the polar regions?
Not just to the polar regions of Mars but wherever they land. It's just that in the polar regions they get frozen over and get preserved in that way for possibly billions of years.

Don J
2013-May-21, 03:03 AM
.. and thus also showing that the 'apparent metabolism' displayed by the unshielded sample, was uneffected by eons of exposure to UV at the surface … which would be an unexpected result, if the sample contained Earth-like, (complex organic molecular) based microbiology ...

In fact the sample from Viking 1 was coming from trench(s) digged by the Lander sampling arm...
http://nssdc.gsfc.nasa.gov/imgcat/html/object_page/vl1_11d128.html


The Viking 1 Lander sampling arm created a number of deep trenches as part of the surface composition and biology experiments on Mars. The digging tool on the sampling arm (at lower center) could scoop up samples of material and deposit them into the appropriate experiment. Some holes were dug deeper to study soil which was not affected by solar radiation and weathering. The trenches in this ESE looking image are in the "Sandy Flats" area of the landing site at Chryse Planitia. The boom holding the meteorology sensors is at left. (Viking 1 Lander, 11D128)



Apparently, it wasn't UV which killed off the 'apparent metabolism'.
The current hypothesis is that the 'deactivation' was achieved courtesy of chloromethane/dichloromethane by-products, produced during the heating in the reaction chamber combined with the interaction of organics and perchlorate (with perchlorate being confirmed to be present within the vicinity of Phoenix, to the north, and now Curiosity (to the East?)
Just because Levin is using the results to make his point, doesn't mean it doesn't also show other things ...

Nothing killed off the metabolism detected by the LR instrument the results were positive.However that is right that the GCMS instrument whose function was to detect the organic compounds was "deactivated" by the effect you describe.The fact that chloromethane/dichloromethane by-products was present in the GCMS datas demonstrate that organic compounds and perchlorate were present in the Mars soil sample(s) analysed... The indirect evidence of the presence of organics compounds in the Martian soil samples combined with the positive LR results demonstrate that the LR instrument have effectively detected a metabolic reaction which on Earth is exclusively produced by living microorganisms present in the soil.

Selfsim
2013-May-21, 03:48 AM
Yeah, the weight comes after the idea is put to the test. But without the idea there is nothing to test.Moot point.

What is presently known?Complex organics were unambiguously discovered from particles collected by Stardust from 81P. No complex organics have been unambiguously detected on Mars. Your hypothetical was the opposite of that.

I'm more interested in discussing possible ways of knowing more in the future. One proposal is that we humans should investigate the different water ices on the Moon, Mars, comets, and now Mercury and compare their organic contents. There will certainly be something important to learn from that.Maybe .. maybe not.
Without results, we don't know that.
'Important' is another one of those meaningless Astrobiological terms, frequently applied before an actual measurement. It is usually speculation prior to the measurement, and thus contributes little/nothing to empirical knowledge.

Yes some organics and water are delivered by comets and meteorites, also by micro meteorites. These are some of the ways water and organics gets onto a planetary body. This seems to be generally the way the solar system works. They've even discovered ice with what looks like concentrations of complex organics on Mercury's poles.Speculation? (See underlines).
The hypothesis of delivery of complex organics by meteorites and comets, is also 'under test' ... by measuring the geological composition on other planetary bodies.
Assuming its validity and 'importance', in the context of life origins, and then assuming this as the basis of some other speculation, does not add to physical knowledge.

Even if complex organics are delivered to planetary bodies via impactors, this doesn't mean that such molecules stay intact or complex! The resultant substances may in fact be completely useless as a 'bio-marker' and/or irrelevant for abiogenesis research. Its all unknown, and ideas are under test, that's all.


It is becoming more clear now that the Martian surface environment is, as they say, "hostile" to organic molecules. Apparently not .. according to Levin .. based on evidence from the martian LR tests!?!
It may be 'hostile' from a terrestrial, extant bio-organics life perspective, though .. but that's all we have evidence for at the present.
Glycine is a complex bio-organic and is also functional in living organisms, and it seems to have survived exposure to interplanetary and space-based radiation, as it was returned to Earth by Stardust from the tail of 81P!
The statement you make, needs to be worded way more specifically .. making more precise references than 'organic molecules'. Otherwise, it is entirely misleading for the purposes of this discussion. That: 'complex organics' of significance to active bio-chemical processes, has not yet been discovered on Mars, may just be a function of the ever increasing coverage of the test space. This factor, has in no way, come anywhere near being eliminated yet.


.. Not just to the polar regions of Mars but wherever they land. It's just that in the polar regions they get frozen over and get preserved in that way for possibly billions of years.Notice that the two big impact craters on South Polar region of Mars, Hellas Planitia and Argyre Planitia are both thought to have occurred during the Last Heavy Bombardment (LHB) - the precise timing of which is controversial. It also seems that life on Earth may have already existed before the LHB. The Martian impactors therefore may have no bearing on possible martian abiogenesis (pre-biotic, or whatever). They may also not have contained complex organics in the first place, so they they may also represent very little when it comes to hypothesised complex organics in the Southern Polar region (if they do exist there).

Once again hypotheses are under test with Mars exploration .. and cannot supplant the results of generic empirical test measurements! The laboratory equipment on Mars, is not designed to test specific hypotheses (like exo-life presence on Mars). They are designed to detect whatever may be there. IMO, and in this sense, exo-life hypotheses considerations should be kept at arms length, and should certainly be separated from the goal of retrieving readings which eliminate environmental uncertainties. The ambiguity resulting from the Viking life measurements demonstrated the flaw in designing experiments which assume the existence of the target being 'sought, (or hypothesised into 'existence').

Selfsim
2013-May-21, 05:47 AM
In fact the sample from Viking 1 was coming from trench(s) digged by the Lander sampling arm...
http://nssdc.gsfc.nasa.gov/imgcat/html/object_page/vl1_11d128.htmlInteresting ..
How did they know at the time, that the holes were: 'dug deep enough such that the soil was not affected by solar radiation'?
All loose soil on mars has been affected by wind. Wind exposes soil particles to solar radiation.
There have been more extensive models developed since Viking.
They all remain debatable, AIUI.


Nothing killed off the metabolism detected by the LR instrument the results were positive.However that is right that the GCMS instrument whose function was to detect the organic compounds was "deactivated" by the effect you describe.The fact that chloromethane/dichloromethane by-products was present in the GCMS datas demonstrate that organic compounds and perchlorate were present in the Mars soil sample(s) analysed... The indirect evidence of the presence of organics compounds in the Martian soil samples demonstrate that the positive results from LR have effectively discovered metabolic reaction which on Earth is exclusively produced by living microorganisms present in the soil.i) What 'indirect evidence' are you referring to?
ii) AIUI, terrestrial contamination in the sample reaction chamber has not been eliminated as the possible source of some particular type of residual 'organics'(?) (Aside: It beats me how they discount the added 'nutrient' components, from being a source of the mysterious 'organics'(??) )
iii) Even if 'organic compounds' were present in the LR martian soil samples, there is no exclusion of the possibility that the particular composition of them, might be capable of producing a positive LR response under ambient martian conditions .. (Any exclusions alluded to by Levin, seems to only be by virtue of his "oppositions' " inability to propose a viable mixture of organics, which replicates the martian results. This would seem to allow for things which they so far, simply haven't yet proposed(?) .. Which would seem to be a pretty poor basis for excluding unknowns!

I, (for eg), know that some classes of organic reactions can behave as oscillators under certain conditions. They aren't considered to be metabolising organics, either. Has this class of organic reactions been considered as a possibility?

This section of Levin's document also sets off alarm bells with me (page 6):
d. Second Injection of nutrient:
Although not part of the official criteria for a biological response, a second injection of nutrient solution was made after completion of the nominal eight days of the LR experiment. There was an immediate re-absorption of approximately 20% of the headspace gas, as seen in Figure 4. Saying that the second injection should have produced a new evolution of gas, many critics cited this as evidence against biology. However, as seen in Figure 5, one of the Antarctic soils tested by the LR showed a similar re-adsorption of headspace gas. This indicates that the organisms died during the test period, and that, when wetted again, the soil re-adsorbed gas.Why didn't he confirm that the Antarctic organisms did actually die? If he did this, he certainly hasn't stated this unequivocally. Why not? Is he speculating here?

Secondly, notice that the soil demonstrates readsorption of the nutrient without subsequent evolution of isotopically marked gases, (during this phase). This could also indicate that the active components had reached an equilibrium state, and further addition of nutrients would thus have little/no effect from thereon. 'Death' of the hypothesised organisms is another hypothesis. There may be other hypotheses … more data is needed .. not just Levin's say-so.

Don J
2013-May-21, 06:37 PM
i) What 'indirect evidence' are you referring to?

-chloromethane and dichloromethane- are a by-product caused by the rapid destruction of the organic compounds by the perchlorate when the perchlorate is heated at 200+ degree celsius ...see page 7 pdf so the fact that the GCMS detected chloromethane and dichloromethane is the indirect evidence that organic compounds were present in the Martian soil samples as well as perchlorate.
mckay


On a paper published in December 2010,[15] the scientists suggest that if organics were present, they would not have been detected because when the soil is heated to check for organics, perchlorate destroys them rapidly producing chloromethane and dichloromethane, which is what the Viking landers found.

Navarro–Gonzáles, Rafael; Edgar Vargas, José de la Rosa, Alejandro C. Raga, Christopher P. McKay (15 December 2010). "Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars". Journal of Geophysical Research – Planets 115 (E12010).
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf


Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.




ii) AIUI, terrestrial contamination in the sample reaction chamber has not been eliminated as the possible source of some particular type of residual 'organics'(?) (Aside: It beats me how they discount the added 'nutrient' components, from being a source of the mysterious 'organics'(??) )

The only thing detected during a blank test made during Mars travel was the products used to clean the oven and chamber reaction on both Viking.


iii) Even if 'organic compounds' were present in the LR martian soil samples, there is no exclusion of the possibility that the particular composition of them, might be capable of producing a positive LR response under ambient martian conditions .. (Any exclusions alluded to by Levin, seems to only be by virtue of his "oppositions' " inability to propose a viable mixture of organics, which replicates the martian results. This would seem to allow for things which they so far, simply haven't yet proposed(?) .. Which would seem to be a pretty poor basis for excluding unknowns!

The burden of the proof is on the side of the detractors to prove that other explanations can provide the same datas detected by the Viking LR...until now at least 40 theories were presented no one was peer-reviewed and no one was able to replicate the LR datas.


I, (for eg), know that some classes of organic reactions can behave as oscillators under certain conditions. They aren't considered to be metabolising organics, either. Has this class of organic reactions been considered as a possibility?

Maybe you can work on that and try to replicate the Viking LR positive results backed with a peer-reviewed paper.

TooMany
2013-May-21, 07:38 PM
.. A simple UV opaque barrier prevents this from happening … like hiding them behind a rock!
Let me see .. oh yeah .. Viking already did that test ..

To listen to NASA scientists, I'm not sure Viking successfully tested anything, let alone whether there are organics behind rocks. And, if you want to test where there is no UV exposure, behind a rock is not going to do the job.



You mean like what happens each season on the polar regions of Mars?

What I mean is that there is nothing that approaches the power of weathering processes on Earth on Mars. It is nearly airless (relative to our atmosphere) there is little to no moving surface water. So if there are organics under the surface, I would not expect to see significant quantities moving to the surface to keep up with the breakdown rate from UV and cosmic ray exposure. Don't forget the apparent oxidizing conditions on the surface.



Hmmm .. the presence of extant and past life?

No you misunderstand. What I'm referring to is the potential for organics is not obviously all that different on Mars than Earth. You are referring to the synthesis by life processes of more complex organics from simpler ones on Earth. I am referring to the carbon and organic endowment of the planets in the first place. It really isn't settled how earth gots it's endowment of carbon and early organic compounds. They may have been inherent, they may have been delivered by comets or some combination. The similarity of the two planets poses no obvious mechanism for Mars to be devoid of organics while Earth is rich in them.



… Notice that how I answer, doesn't have to have anything to do with empirical reality .. (in a speculation forum).

No it does not. But we don't send robots to Mars to search for conditions supportive of life because we have already empirical knowledge that such conditions existed. This is a point to you seem unable to accept - that science usually speculates and then undertakes experiment to provide empirical evidence, not the other way around.

Selfsim
2013-May-22, 12:07 AM
To listen to NASA scientists, I'm not sure Viking successfully tested anything, let alone whether there are organics behind rocks. And, if you want to test where there is no UV exposure, behind a rock is not going to do the job.See page 5 of the PDF (post 1)
http://www.gillevin.com/Mars/THE_VIK...FE_ON_MARS.pdf (http://www.gillevin.com/Mars/THE_VIKING_MISSION_AND_LIFE_ON_MARS.pdf)
"After the first LR positive result....
Some astrobiologists immediately suggested that the Martian soil was "activated" by the UV light hitting it. We quickly eliminated that theory by moving a rock at dawn and testing the soil underneath. It was fully active."(Quote courtesy of Don J .. thanks Don!)


What I mean is that there is nothing that approaches the power of weathering processes on Earth on Mars. It is nearly airless (relative to our atmosphere) there is little to no moving surface water. So if there are organics under the surface, I would not expect to see significant quantities moving to the surface to keep up with the breakdown rate from UV and cosmic ray exposure. Don't forget the apparent oxidizing conditions on the surface.Apparently, the UV and oxidant on the very surface, doesn't prevent the detection of active, 'apparent' metabolism!
(See above quote from Levin on Viking Mars LR test results).


No you misunderstand. What I'm referring to is the potential for organics is not obviously all that different on Mars than Earth. You are referring to the synthesis by life processes of more complex organics from simpler ones on Earth.The bulk of soil organics on Earth, has been shown, (via extensive, replicable lab testing and sampling), to come from detritus and microbiological decomposition of past life, (which incidentally results in simpler organic compounds). You might be speaking about 'potential for organics', which would be speculation. I am speaking about empirical fact. The two are not comparable. The empirical fact is what we know. We don't know anything from pure speculation.


I am referring to the carbon and organic endowment of the planets in the first place. It really isn't settled how earth gots it's endowment of carbon and early organic compounds. They may have been inherent, they may have been delivered by comets or some combination. The similarity of the two planets poses no obvious mechanism for Mars to be devoid of organics while Earth is rich in them.Working backwards in time from known empirically established fact, the presence of life, and past life, is the known cause of the bulk of the organics buildup on Earth. Anything else is just speculation .. which is currently under test by exploration of planets like Mars. The speculation can be changed instantly, in the face of unambiguous test results … the facts can't be changed to suit the story, however.


No it does not. But we don't send robots to Mars to search for conditions supportive of life because we have already empirical knowledge that such conditions existed. This is a point to you seem unable to accept - that science usually speculates and then undertakes experiment to provide empirical evidence, not the other way around.Is that speculation .. or are you saying these opinions are a reality?

Scientific experimental method (http://en.wikipedia.org/wiki/Experiment) ..
.. is an orderly procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis.This is a fundamentally different statement from "science usually speculates and then undertakes experiment to provide empirical evidence", because the speculation can be rendered 'false', by the observation of something else found to be 'true'. (Provided the experiment is capable of eliminating uncertainty). Speculation which might lead to a hypothesis, is thus entirely uncertain, prior to testing the hypothesis, and thus carries little/no scientific weight.

The impetus for launching exploratory interplanetary probes, is built partly on a repository of astronomical observational data at hand. Real scientific speculation is based on prior empirically sourced data … not stories.

ASTRO BOY
2013-May-22, 12:16 AM
Speculation which might lead to a hypothesis, is thus entirely uncertain, prior to testing the hypothesis, and thus carries little/no scientific weight.

.


I suppose we can be thankful then that some speculation carries plenty of scientific weight...otherwise we could still be swinging in the trees!

ASTRO BOY
2013-May-22, 02:26 AM
I suppose we can be thankful then that some speculation carries plenty of scientific weight...otherwise we could still be swinging in the trees!

Examples of course are the "speculative" assumptions of homegenity and Isotropy, as logical as they certainly are, and to paraphrase someone in another thread, we once could "logically" speculate/assume that the far side of the Moon was cratered similar to the near side.
Too much to do at present to think of the myriad of other logical speculative assumptions/ideas but that should suffice.

Selfsim
2013-May-22, 03:05 AM
-chloromethane and dichloromethane- are a by-product caused by the rapid destruction of the organic compounds by the perchlorate when the perchlorate is heated at 200+ degree celsius ...see page 7 pdf so the fact that the GCMS detected chloromethane and dichloromethane is the indirect evidence that organic compounds were present in the Martian soil samples as well as perchlorate.
mckay

Navarro–Gonzáles, Rafael; Edgar Vargas, José de la Rosa, Alejandro C. Raga, Christopher P. McKay (15 December 2010). "Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars". Journal of Geophysical Research – Planets 115 (E12010).
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf
Ok .. thanks for that .. just a slight wording misunderstanding. (I thought you may have been referring to some other external separate test, etc .. )

'Organic carbon', eh? .. But where and what is it?
(It'd be great if something turned up in Curiosity's Cumberland's SAM results ..) :)


The only thing detected during a blank test made during Mars travel was the products used to clean the oven and chamber reaction on both Viking.Viking 1 TV GCMS showed the presence of Freon E type and absorbed water .. For Viking 2:
.. but the subsystem involved in the soil analysis, namely, the sample ovens and the tubing and valves prior to and possibly after the gas chromatographic column, were not as clean [Biemann et al., 1977]... They go on to conclude that the (di)chloromethane(s) were 'most likely' synthesised in part from primarily the soil sample contents … (not the original contaminants) because none of the contaminating compounds in question, were detected at the same concentration levels (on the blank runs) needed to generate the (di)chloromethanes detected in the active sample runs (on Viking 1).
Anyway, I think we quoted Mahaffy(?) as saying they detected (di)chloromethanes from the Curiosity John Klein drilling (… from memory .. I think??)

( … Just confirming what I think we're both agreeing on here ..)


The burden of the proof is on the side of the detractors to prove that other explanations can provide the same datas detected by the Viking LR...until now at least 40 theories were presented no one was peer-reviewed and no one was able to replicate the LR datas.I don't agree that life can be declared on the basis of an: 'hypothesis of best fit', which in itself is based on an experiment whose results were ambiguous, regardless of how good the explanation for that ambiguity is. And that may be dependent on the type soil organics detected by Curiosity, (if any), from Gale Crater … then again, it may not … because of the geographical separation and different terrain of Viking's test area compared with Curiosity's.

'Burdens of proof' only become relevant when there is no ambiguity in the test results underpinning the hypothesis/theory. Unfortunately, in the case of Viking's tests, there always will be ambiguity. .. ("Extraordinary claims …"??)


Maybe you can work on that and try to replicate the Viking LR positive results backed with a peer-reviewed paper.Nice try … :)

Selfsim
2013-May-22, 03:28 AM
Examples of course are the "speculative" assumptions of homegenity and Isotropy, as logical as they certainly are, The combination of these form the Cosmological Principle, and are backed by the bulk of Astronomical observations to date, and Physical Laws. Individually, they are working assumptions, and are appropriately presented as being subject to falsification by experiment, or other replicable observations/measurements (which are actively pursued).

They are not simply 'speculative assumptions' and it is regarded as inappropriate to claim that they are.


… and to paraphrase someone in another thread, we once could "logically" speculate/assume that the far side of the Moon was cratered similar to the near side. .. and so??

The 'logicality' of some speculation, still carries little/no weight, until empirical testing produces its results. (Which is a core theme of the Viking tests, and of this thread, actually).

'Logicality' is philosophy … and does not supplant knowledge derived from empirical science!
To suggest it does, is mantra from meta-physics, (and that's being polite about it), .. which quite distinct from science).

Don J
2013-May-22, 03:35 AM
I don't agree that life can be declared on the basis of an: 'hypothesis of best fit', which in itself is based on an experiment whose results were ambiguous, regardless of how good the explanation for that ambiguity is. And that may be dependent on the type soil organics detected by Curiosity, (if any), from Gale Crater … then again, it may not … because of the geographical separation and different terrain of Viking's test area compared with Curiosity's.

'Burdens of proof' only become relevant when there is no ambiguity in the test results underpinning the hypothesis/theory. Unfortunately, in the case of Viking's tests, there always will be ambiguity. .. ("Extraordinary claims …"??)

The finding of a circadian rythm in the Viking LR datas- combined with the LR positive results + the demonstrated possibility that there was organic compounds in the Martian soil samples analysed(post 169)- would be a good indication that Viking did indeed find life on Mars.


Circadian rhythms are internal clocks found in every known life-form—including microbes—that help control biological processes, such as waking, sleeping, and temperature regulation.

On Earth this clock is set to a 24-hour cycle, but on Mars it would be about 24.7 hours—the length of a Martian day.

Guess what, a Martian circadian rythm was discovered in the Viking LR datas:
http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/
Evidence for Martian Rhythm

Still, the new findings are consistent with a previous study published by Miller, in which his team found signs of a Martian circadian rhythm in the Viking LR experiment results.

Circadian rhythms are internal clocks found in every known life-form—including microbes—that help control biological processes, such as waking, sleeping, and temperature regulation.

On Earth this clock is set to a 24-hour cycle, but on Mars it would be about 24.7 hours—the length of a Martian day.

In his previous work, Miller noticed that the LR experiment's radiation measurements varied with the time of day on Mars.

"If you look closely, you could see that the [radioactive-gas measurement] was going up during the day and coming down at night. ... The oscillations had a period of 24.66 hours just about on the nose," Miller said.

"That is basically a circadian rhythm, and we think circadian rhythms are a good signal for life."

Selfsim
2013-May-22, 04:04 AM
The finding of a circadian rythm in the Viking LR datas- combined with the LR positive results + the demonstrated possibility that there was organic compounds in the Martian soil samples analysed(post 169)- would be a good indication that Viking did indeed find life on Mars.Tee hee .. Ok .. 'good indication' is pretty innocuous .. in this case, because of the legitmately solid background work that's clearly been done for Viking (and over recent times), I just may be able to live with that … (just maybe, though .. :) )
(PS: What 'I think' doesn't really count for much though, eh? Let's get some data! :) )


Guess what(?) a Martian circadian rythm was discovered in the Viking LR datas:
http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/
Evidence for Martian Rhythm

Still, the new findings are consistent with a previous study published by Miller, in which his team found signs of a Martian circadian rhythm in the Viking LR experiment results.

Circadian rhythms are internal clocks found in every known life-form—including microbes—that help control biological processes, such as waking, sleeping, and temperature regulation.

On Earth this clock is set to a 24-hour cycle, but on Mars it would be about 24.7 hours—the length of a Martian day.

In his previous work, Miller noticed that the LR experiment's radiation measurements varied with the time of day on Mars.

"If you look closely, you could see that the [radioactive-gas measurement] was going up during the day and coming down at night. ... The oscillations had a period of 24.66 hours just about on the nose," Miller said.

"That is basically a circadian rhythm, and we think circadian rhythms are a good signal for life."This is the 'complexity analysis' study applied to the Viking data, eh? ...

The team concedes, however, that this finding by itself isn't enough to prove that there's life on Mars.
"It just says there's a big difference between the active experiments and the controls, and that Viking's active experiments sorted with terrestrial biology and the controls sorted with nonbiological phenomena," Miller said.
Cheers

Don J
2013-May-22, 04:13 AM
Interesting ..
How did they know at the time, that the holes were: 'dug deep enough such that the soil was not affected by solar radiation'?
All loose soil on mars has been affected by wind. Wind exposes soil particles to solar radiation.

You can have the datas about how deep they digged , also the under the rock sample collected by Viking 2. (Biology Sampling Under Notch Rock)

Good reading!
Collecting Soil Samples
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL%202%20Primary

All LR datas from Viking lander VL1 and VL2 ...
Viking Lander Labeled Release
Experimenter's Notebook
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htm

Don J
2013-May-22, 04:30 AM
Tee hee .. Ok .. 'good indication' is pretty innocuous .. in this case, because of the legitmately solid background work that's clearly been done for Viking (and over recent times), I just may be able to live with that … (just maybe, though .. :) )
(PS: What 'I think' doesn't really count for much though, eh? Let's get some data! :) )

ETA
Well, the right wording from the article is rather very probant:
http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/
"That is basically a circadian rhythm, and we think circadian rhythms are a good signal for life."
So now the detractors will have to find an explanation also for the Martian circadian rythm whose on Earth is associated with life.Do you have the explanation?


This is the 'complexity analysis' study applied to the Viking data, eh? ...

No,the complexity analysis study applied to the Viking data is here: (provided in post 169)That you chosed to ignore!!!
Navarro–Gonzáles, Rafael; Edgar Vargas, José de la Rosa, Alejandro C. Raga, Christopher P. McKay (15 December 2010). "Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars". Journal of Geophysical Research
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf
ETA 2
If you want to make your own reevaluation of the Viking LR datas see:
Viking Lander Labeled Release Experimenter's Notebook
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htm

Cheers!
--------------
Waiting for the Video of Martian bacteria sitting in a petri dish.
http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/


Despite his own conviction that the Viking mission detected life on Mars, Miller said he doesn't expect most people will be convinced until they can look at a video of Martian bacteria sitting in a petri dish.

"But for some reason, NASA has never flown a microscope that would let you do something like that," he said. "If they can fly a microscope for the geologists, they should be able to fly one for the biologists."

Based on the bolded part above and the demonstrared fact that NASA forbid any life detection experiments since Viking....it seem more and more evident that the quest for life on Mars (past or present) seem preferable for those making a living from Martian missions than finding a definitive proof of it existence.


Miller said he doesn't expect most people will be convinced until they can look at a video of Martian bacteria sitting in a petri dish.

But we know that NASA will never set that kind of mission experiment as pointed out by Miller.


But for some reason, NASA has never flown a microscope that would let you do something like that," he said. "If they can fly a microscope for the geologists, they should be able to fly one for the biologists."

ASTRO BOY
2013-May-22, 04:41 AM
The combination of these form the Cosmological Principle, and are backed by the bulk of Astronomical observations to date, and Physical Laws. Individually, they are working assumptions, and are appropriately presented as being subject to falsification by experiment, or other replicable observations/measurements (which are actively pursued).

They are not simply 'speculative assumptions' and it is regarded as inappropriate to claim that they are.


All scientific theories are subject to possible falsification...that's the name of the game and part of what science is. And logical speculation is part of that.
Plus I don't believe it is innapropriate...but as I said, we have many more examples.





T
.. and so??

??? And so we have another example of logical speculation....




The 'logicality' of some speculation, still carries little/no weight, until empirical testing produces its results. (Which is a core theme of the Viking tests, and of this thread, actually).

Bingo!!!! Some speculation...not all speculation.
Some have/do carry plenty of scientific weight.





'Logicality' is philosophy … and does not supplant knowledge derived from empirical science!
To suggest it does, is mantra from meta-physics, (and that's being polite about it), .. which quite distinct from science).


Again something I have never said. Naturally new found knowledge may support logical speculation or invalidate it.
Examples of both are evident. I'm quite enthusiastic about going where we have not gone before to obtain whatever knowledge is waiting there to be obtained.
In summing you seem to be "splitting hairs" and being pedant on some matters, while misquoting or misinterpreting on others.

Paul Wally
2013-May-22, 05:08 PM
Speculation? (See underlines).
The hypothesis of delivery of complex organics by meteorites and comets, is also 'under test' ... by measuring the geological composition on other planetary bodies.
Assuming its validity and 'importance', in the context of life origins, and then assuming this as the basis of some other speculation, does not add to physical knowledge.

Even if complex organics are delivered to planetary bodies via impactors, this doesn't mean that such molecules stay intact or complex! The resultant substances may in fact be completely useless as a 'bio-marker' and/or irrelevant for abiogenesis research. Its all unknown, and ideas are under test, that's all.


Really? How about some carbonaceous chondrite (http://en.wikipedia.org/wiki/Carbonaceous_chondrite) and also check out the Murchison meteorite (http://en.wikipedia.org/wiki/Murchison_meteorite) which was seen falling from the sky in Australia. Why would these meteorites, which are rich in complex organics, land on Earth and somehow avoid falling on Mars over a period of billions of years? It is quite obvious that
complex organic molecules must have landed on Mars in tact. So either they are still there on Mars today or they've been destroyed by some process.


Glycine is a complex bio-organic and is also functional in living organisms, and it seems to have survived exposure to interplanetary and space-based radiation, as it was returned to Earth by Stardust from the tail of 81P!

Compare that to geological timescale exposure on the Martian surface.



Notice that the two big impact craters on South Polar region of Mars, Hellas Planitia and Argyre Planitia are both thought to have occurred during the Last Heavy Bombardment (LHB) - the precise timing of which is controversial. It also seems that life on Earth may have already existed before the LHB. The Martian impactors therefore may have no bearing on possible martian abiogenesis (pre-biotic, or whatever). They may also not have contained complex organics in the first place, so they they may also represent very little when it comes to hypothesised complex organics in the Southern Polar region (if they do exist there).

Why would none of all the meteorites that has ever fallen on Mars contain complex organics. It's a statistical improbability.

Selfsim
2013-May-23, 12:15 AM
Really? How about some carbonaceous chondrite (http://en.wikipedia.org/wiki/Carbonaceous_chondrite) and also check out the Murchison meteorite (http://en.wikipedia.org/wiki/Murchison_meteorite) which was seen falling from the sky in Australia. Why would these meteorites, which are rich in complex organics, land on Earth and somehow avoid falling on Mars over a period of billions of years? It is quite obvious that
complex organic molecules must have landed on Mars in tact. So either they are still there on Mars today or they've been destroyed by some process. Again, you use a demanding question posed from a hypothetical paradigm, answer it yourself (in the negative), and then infer there can be no other explanation other than what you insist upon … all in the absence of empirical data of relevance in the first place, ie: in this case, the presence of said organics on Mars!

Your point is not my point! You are attempting to defend an hypothesis using logical arguments, in a thread which attempts to focus discussion on the opportunity of actually 'going where the empirical test data leads'!

My point is that the hypothesis is presently being put to the test, by the geological detailed exploration of an impact crater on Mars, where the hypothesis predicts the presence of organics .. and so far, no 'complex organics' (of bio-significance) have been identified.

'Complex organics' of 'bio-significance', weren't found in return sample Lunar rocks, nor in Lunar meteorite samples. Mars' incident UV radiation did not prevent the detection of 'apparent metabolism'. 'Complex organics', of 'bio-significance', were found in some carbonaceous chondritic meteorite deposits on Earth. A comet (81P) was also found to expel 'complex organics' of 'bio-significance'. All of these objects have been exposed to varying degrees and intensities by UV/cosmic radiation. … 'Them is the facts' ... and they are what establishes the reality of what we now know … and not argued hypotheses built around them!

What we find on Mars, is another (rare) opportunity to extend that reality .. (bring on the test data).


Compare that to geological timescale exposure on the Martian surface.Do we know how long the surface materials of that comet were exposed to radiation? How long would that be, compared with Mars' case/incident intensities? How do we know this?
(Note: 81P exhibited copper sulfide which (so far) is known to form in the presence of water. This conflicts with the 'cold comet' hypothesis. Radiogenic heating is one counter-hypothesis. How does longterm exposure to radioactive decay also not 'destroy' complex organics (like Gylcine)? .. (Do you see why 'logical hypotheses' do not establish empirical fact?) )


Why would none of all the meteorites that has ever fallen on Mars contain complex organics. It's a statistical improbability.Why is it a statistical improbability? Please demonstrate excluding speculative hypotheses. (Please include: that there were no complex organics found in the returned moon rock samples (also presumably including hypothetical meteoric ancestry), and terrestrially sourced Lunar meteorite samples).

Now, planetary formation hypotheses have been established as a way of providing a working explanation consistent with facts (to varying degrees) .. but that hypothesis isn't what establishes physical reality, is it?

Please note (for readers): My point here, is not to make claims of (or advocate) alternatives to mainstream adopted hypotheses. My point here is that mainstream hypotheses do not supplant the physical reality established from non-terrestrially sourced empirical test data. If such data is absent, we should go get it .. hypotheses always remain the variables.

Selfsim
2013-May-23, 02:13 AM
You can have the datas about how deep they digged , also the under the rock sample collected by Viking 2. (Biology Sampling Under Notch Rock)

Good reading!
Collecting Soil Samples
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL%202%20Primary

All LR datas from Viking lander VL1 and VL2 ...
Viking Lander Labeled Release
Experimenter's Notebook
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htmThanks for those links.

Very interesting.

I notice the GEX, PR and GCMS results are notably absent from those pages.

There's a lot of material around about the GCMS controversy, but most of it is not current.

Anyway, the notebook link above, answers my questions about what was in the 'chicken soup'. I have a few questions about the state of cleanliness of the LR chamber following injection of these nutrients .. (but I suspect this was already exhaustively checked out, though .?.). Presumably residual organics from this concoction couldn't have effected subsequent LR (or GCMS) results(?)
They also seem to heat the sample in the LR chamber (only to about 10 or 15 degrees) ..lots going on there, methinks. (Just thinking out aloud here .. not sure what to make of that ..)

Seems the trenches were only a couple of inches deep .. yet the 'apparent metabolism' was uneffected by UV exposure at those depths. The radioactivity count seems to rise and fall in sympathy with the 'head temperature'. (There's almost a direct correlation with that .. not sure what to make of that, though ..)

Selfsim
2013-May-23, 02:36 AM
ETA
Well, the right wording from the article is rather very probant:
http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/
"That is basically a circadian rhythm, and we think circadian rhythms are a good signal for life."
So now the detractors will have to find an explanation also for the Martian circadian rythm whose on Earth is associated with life.Do you have the explanation?Well, I'm reminded of the patterns some cosmologists 'read into' the WMAP CMBR measurements.

Seriously though, the initial setting out assumptions are extremely formulaic. (Some might call them 'optimistic'). The circadian rhythm hypothesis, is just another hypothesis.
I still question the influence the original assumptions might have had on an experiment design, which was highly focused on finding specifically Earth-like microbacteria. (Whilst I 'get' that this might be appropriate for a non-terrestrial carbon-based lifeform test, the main question arising from the ambiguity resulting, in retrospect (and admittedly, somewhat unfairly with the aided benefit of hindsight) is:

"Was testing this hypothesis ever likely to optimise potential scientific return-on-investment, when compared with more generalised testing?"
I would say what's happened since Viking, represents the answer to that question. Still, frankly I can't see why sending a small microscope is such a big deal .. but that's one for the probe design teams to answer.


No,the complexity analysis study applied to the Viking data is here: (provided in post 169)That you chosed to ignore!!!
Navarro–Gonzáles, Rafael; Edgar Vargas, José de la Rosa, Alejandro C. Raga, Christopher P. McKay (15 December 2010). "Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars". Journal of Geophysical Research
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf
Not ignored .. (I read it). There was a lot of information to process and a lot of flak on this thread to respond to.
No direct response means nothing!


ETA 2Waiting for the Video of Martian bacteria sitting in a petri dish.
http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/

Despite his own conviction that the Viking mission detected life on Mars, Miller said he doesn't expect most people will be convinced until they can look at a video of Martian bacteria sitting in a petri dish.

"But for some reason, NASA has never flown a microscope that would let you do something like that," he said. "If they can fly a microscope for the geologists, they should be able to fly one for the biologists."Based on the bolded part above and the demonstrared fact that NASA forbid any life detection experiments since Viking....it seem more and more evident that the quest for life on Mars (past or present) seem preferable for those making a living from Martian missions than finding a definitive proof of it existence.

But we know that NASA will never set that kind of mission experiment as pointed out by Miller."Was testing this hypothesis ever likely to optimise potential scientific return-on-investment, when compared with more generalised testing?"

Don J
2013-May-23, 04:28 AM
Seems the trenches were only a couple of inches deep .. yet the 'apparent metabolism' was uneffected by UV exposure at those depths.
That means that the action of the UV is affecting only a thin layer of the surface of the Martian soil.
Do you have a study demonstrating that the UV are so powerfull that they are able to penetrate through the soil at a couple of inches deep ?
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL%201%20Primary

Selfsim
2013-May-23, 07:47 AM
That means that the action of the UV is affecting only a thin layer of the surface of the Martian soil.
Do you have a study demonstrating that the UV are so powerfull that they are able to penetrate through the soil at a couple of inches deep ?
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL%201%20PrimaryOk .. now I understand.

Yep .. the recent study: "Effects of Long-Term Simulated Martian Conditions on a Freeze-Dried and Homogenized Bacterial Permafrost Community (http://www.ncbi.nlm.nih.gov/pubmed/19371163)". (Aviaja Hansen, Lars Jensen etal), drew the conclusions that:

persistent long-term forward contamination of Mars is unlikely as long as bacterial cells are deposited in the upper 2 cm of the martian surface dust" and that "Biomolecules, such as bacterial DNA and proteins, were more resistant to destruction than the bacteria themselves.

Another current relevant study is: "Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions (http://www.ncbi.nlm.nih.gov/pubmed/19371162)." (David Smith, Andrew Schuerger, etal). They conclude that:

Though certain terrestrial bacteria pose a serious contamination threat to Mars, the researchers found that the bacterium tested could not survive the UV levels typically found on the martian surface.... Viking's trenches were 2.5 cms (VL2 from under Notch Rock), to about 5 cms (VL1 Sandy Flats).

So, in theory, we should see more apparent LR activity from the deeper samples ... (I don't think this can easily be established from the Viking LR results, unfortunately).

(I was assuming the 'depth of survival' was something more along the lines of McKay's Ice-Drill '3 feet or greater' depth (or a little less) .. not the 2cms concluded above).

And then we have this from Wiki: (http://en.wikipedia.org/wiki/Manned_mission_to_Mars#Longevity_of_endospores_and _resistance_to_Mars_surface_conditions)


The Expose E experiment on the International Space Station included a simulation of exposure to the Mars surface and produced stunning results. When they were in multi-layers, 5% of spores were able to survive on the surface for at least 125 days (3,000 hours) exposed to direct Martian daylight (simulated by filtering the direct light from the sun to Martian levels). An appreciable quantity of spores were able to survive the same period even in monolayers. Then 70-75% of the initial population survive the same period on the simulated Mars surface in shadows.
The spores used were of two species, Bacillus pumilus SAFR-032 isolated from an air lock of the spacecraft assembly facility at the Jet Propulsion Laboratory, which showed elevated resistance to UV radiation and hydrogen peroxide treatment compared to the wild-type strain, and Bacillus subtilis, which is found in soil and in the human gut.

So, following the Expose E paradigm, if Earth-like life can achieve such UV hardiness (& survivability) when removed from their terrestrial habitat, why did Curiosity's SAM not detect Mars' Evolved complex organics at Rocknest and Klein?

So other questions (just out of my own curiosity ...)
Why wouldn't Mars micro-organisms have adapted a defense mechanism against surface UV exposure? (Lots of terrestrial organisms have achieved this ...). Why haven't the first two mentioned studies above, taken this into consideration? Why don't we see macro signs of micro-organisms on Mars' surface rocks? (I know Levin thinks there may be such signs ... but the photos he was working from, were very grainy and later photos from Opportunity, Phoenix and Curiosity showed no signs ...).

Overall, the '2cms' hypothesis and Viking LR/Expose E and Evolutionary Theory, seem to be trying to explain: 'no surface life on Mars', and 'surface life on Mars', (respectively).
:confused:
Rather than trying to explain/answer all these questions with yet another hypothesis, we should put aside all these 'hypotheses' and 'analogue/models', for the time being, and get on with gathering the data! (IMO). SAM is the opportunity before us! Let's use it (while it lasts)!

Don J
2013-May-23, 06:05 PM
Ok .. now I understand.

Yep .. the recent study: "Effects of Long-Term Simulated Martian Conditions on a Freeze-Dried and Homogenized Bacterial Permafrost Community (http://www.ncbi.nlm.nih.gov/pubmed/19371163)". (Aviaja Hansen, Lars Jensen etal), drew the conclusions that:


persistent long-term forward contamination of Mars is unlikely as long as bacterial cells are deposited in the upper 2 cm of the martian surface dust"


... Viking's trenches were 2.5 cms (VL2 from under Notch Rock), to about 5 cms (VL1 Sandy Flats).

So, in theory, we should see more apparent LR activity from the deeper samples ... (I don't think this can easily be established from the Viking LR results, unfortunately).

No need to dig deeper the Viking LR instrument showed positive results -after injection of nutrients- in all the samples ranging from 2.5 cm and 5 cm below the surface which demonstrate that at 2.5 cm and deeper below of the martian surface dust, living Martian microorganisms have adapted and survived.
See the LR graphs and details:
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htm

See VL1 Cycle 1 test with injection of nutrients followed by a control sample test VL1 Cycle 2 heated at 160° C for about 3 hours to sterilize the sample as a control for comparison to VL1 cycle 1 results.+++all the other LR tests.
-Click on display cycle 1 datas for graph.ect-
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/tlframe1.htm

For LR tests made by Viking 2:
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/tlframe2.htm

Selfsim
2013-May-23, 09:07 PM
Ok .. I understand the working hypothesis (Levin's etal).

So let's look at it from the other perspective ...

What would it take to falsify it?

Don J
2013-May-23, 10:54 PM
why did Curiosity's SAM not detect Mars' Evolved complex organics at Rocknest and Klein?

Here a clue,
Untill now Curiosity as only looked for organic compounds by drilling in rocks... NASA scientists are quick to explain that finding organics on Mars will be very hard to do, and that it’s difficult to find organic carbon in rock samples even on Earth.
More:
http://www.space.com/16902-mars-rover-curiosity-life-building-blocks.html

Selfsim
2013-May-24, 03:44 AM
why did Curiosity's SAM not detect Mars' Evolved complex organics at Rocknest and Klein?Here a clue,
Untill now Curiosity as only looked for organic compounds by drilling in rocks... NASA scientists are quick to explain that finding organics on Mars will be very hard to do, and that it’s difficult to find organic carbon in rock samples even on Earth.
More:
http://www.space.com/16902-mars-rover-curiosity-life-building-blocks.htmlWell, that's not entirely true (that's only a Mahaffy comment). Rocknest was a soil drift (not a rock drilled sample).

Also, I refute that: "its difficult to find organic carbon in rock samples on Earth"! (http://en.wikipedia.org/wiki/Organic_carbon#Measurement)
With oceanic particulate organic carbon maps like this (http://en.wikipedia.org/wiki/File:POC.png) or this (http://disc.sci.gsfc.nasa.gov/gesNews/new_ocean_color_radiometry_products), or this, (http://disc.sci.gsfc.nasa.gov/giovanni/additional/newsletters/giovanni-news-newsletters/giovanni_news_March_2010) his statement is either close to bunkum, or shows that he is simply throwing the public a 'low-ball', to cover the possibility of a non-finding, following so much hype about martian 'organics'.

According to that rather well-written article, (IMO), which summarises the 'to-ing and fro-ing' about all this, there are many opinions, some at odds with others;

- Grunsfield says "we'll find out soon enough';
- Mahaffy says: "finding organics will be very hard to do .. but he sees some real opportunities';
- Steele concluded that the organics <in terrestrially sourced meteorites> "were definitely not the result of terrestrial contamination and so were possibly from Mars";
- McKay seems overhwhelmed with the prevalence of organic material (and microbes) on Earth .. but he thinks Curiosity/SAM should be able to find the "gobs" of organics hidden by Mars' perchlorate;

-Biemann: "leader for the Viking GC-MS experiment, has sharply criticized the perchlorate theory. In a published comment on the Navarro-Gonzalez and McKay paper, he and Jeffrey Bada of the Scripps Institution wrote that the theory is based on faulty data and unfounded extrapolations, and that it ignores the known presence of several cleaning compounds found in the GC-MS during the Viking experiments"
They also contend that if the process described by McKay and Navarro-Gonzalez had taken place, that other compounds - in this case other chlorinated aromatic molecules - would also be produced on Mars, yet they were not";

- Biemann and Bada agree that meteorites with 'organic carbon' fall continuously onto Mars, but the organics are destroyed by high energy radiation, which causes the build-up of oxidising agents, so if SAM can't detect 'em … then they don't survive on the surface;

… Then there's the methane(ists);

- Mumma and Geranimo Villaneuva, who put their money on C12/C13 ratio measurements as an indicator of martian 'life.

And Levin of course, who thinks living microbes have already been found.

What a hodgepodge of speculative mumbo-jumbo .. all covering just about any and all ideas the human mind can seemingly dream up!

There's a contrived answer for every contingency …!

Whilst I look forward to, (yep .. opinion), a complex bio-organic-looking molecule turning up, what will be the conclusion if it doesn't?

More of the above kind of stuff, I suspect(?)

Don J
2013-May-24, 04:22 AM
Well, that's not entirely true (that's only a Mahaffy comment). Rocknest was a soil drift (not a rock drilled sample).

Also, I refute that: "its difficult to find organic carbon in rock samples on Earth"! (http://en.wikipedia.org/wiki/Organic_carbon#Measurement)
his statement is either close to bunkum, or shows that he is simply throwing the public a 'low-ball', to cover the possibility of a non-finding, following so much hype about martian 'organics'.

The thing you seem to forget is that the rock -and- the soil drift at Rocknest in which Curiosity have drilled into are billions of years old. Even on Earth, which is teeming with life, it can be difficult to find evidence of it in such old rocks. This is because it is hard to preserve organic material over such long periods of time even if it is present.
_
NASA science team member, Ralph Milliken answers your questions about the Mars Curiosity Rover Mission
http://www.facebook.com/notes/brown-university/nasa-science-team-member-ralph-milliken-answers-your-questions-about-the-mars-cu/10151236671061534


With oceanic particulate organic carbon maps like this (http://en.wikipedia.org/wiki/File:POC.png) or this (http://disc.sci.gsfc.nasa.gov/gesNews/new_ocean_color_radiometry_products), or this, (http://disc.sci.gsfc.nasa.gov/giovanni/additional/newsletters/giovanni-news-newsletters/giovanni_news_March_2010)

Well your ocean mapping example of -particulate organic carbon- is hard to apply to MARS (in the actual Mars environment condition) .I let you figure why?

Selfsim
2013-May-24, 08:51 AM
The thing you seem to forget is that the rock -and- the soil drift at Rocknest in which Curiosity have drilled into are billions of years old. Even on Earth, which is teeming with life, it can be difficult to find evidence of it in such old rocks. This is because it is hard to preserve organic material over such long periods of time even if it is present. I think you may have confused 'organic carbon' with 'organic material' ...(??)... The two terms overlap, and one does not exclusively imply the other. (Remember I mentioned the confusion introduced by the imprecision of Astrobiology, caused by the sloppy usage of terminologies?) This is what Ralph said:
The extreme optimist in me thinks that we might actually find evidence of organic material on Mars, but the rocks we are exploring are likely several billion years old and we know from our experience on Earth that it is very difficult to preserve evidence of life in such old rocks. However, detecting organic material is not a goal of the mission, we are more focused on understanding whether or not Mars had past environments that could have been habitable.Mahaffy used the term: "organic carbon" .. not "organic material". "Organic carbon" covers decomposed residuals derived from (once living) "organic material", but is not exclusively limited to that. Not all organic compounds are created by living organisms, and living organisms do not only leave behind organic material. For instance, a clam's shell, doesn't contain significant amounts of 'organic carbon', so it may not be considered 'organic matter'. Urea however, is one of many organic carbon compounds that can be synthesized without any biological activity.

So, 'organic carbon' (compounds) can exist for eons, and may not necessarily have come from living things, and I don't see any real reason why it wouldn't be well dispersed all over the surface, (if indeed, Mars was well-sprinkled by meteorite impacts(?)). None was detected in the wind drift soil sample (note: not a rock drilling), called 'Rocknest' (according to Mahaffy).

Well your ocean mapping example of -particulate organic carbon- is hard to apply to MARS (in the actual Mars environment condition) .I let you figure why?The point was that 'organic carbon', is abundant on Earth .. and thus, not at all hard to find. The maps demonstrate the widespread distribution of it (albeit, courtesy of the oceans .. which ultimately participate in the formation of sedimentary rocks, which commonly bear organic carbon). As that organic carbon does not necessarily have to have come from past living matter, measurable amounts of it should be present in sedimentary rocks, like those presently being encountered by Curiosity. The evaporite sedimentary minerals on Mars, should surely contain some portion of organic carbon compounds, but according to Mahaffy .. none were detected.

... All of the above, I think, is consistent ... if we truly are following the terrestrial models in all of this speculation, that is ...

Selfsim
2013-May-24, 11:05 AM
I think the problem here is that the Klein sample was heated in the GCMS. (http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=5126) Dichloromethane and chloromethane was produced.

I don't think they've attempted to use the 'wet front-end' functionality of SAM (prior to the GCMS). If they'd done that, then they should have been able to identify whatever organic carbon compounds may have been in the sample.

They only have nine solvent liquid cups to work with .. so I'll bet they're holding off using them until they get to some clay layers at the base of Mt Sharp ... and until they have purged the whole system of any terrestrial contaminants(??)

The reason Mahaffy is saying they haven't detected any martian 'organic carbon', is because they haven't gone looking for it explicitly yet, (ie: using the solvent technique prior to pyrolysis ...)

That makes sense!?!

Interestingly though, the 'blank runs' of GCMS, (done prior to sampling), still showed, (albeit), lower levels of both dichloromethane and chloromethane!
Which shows that there is still residual terrestrial organic carbon somewhere in the system.
So, they may be detecting a combination of both terrestrial residual, and martian organic carbon .. but what are the overall proportions ... and what are the compositions of each proportion?

Paul Wally
2013-May-24, 01:27 PM
Again, you use a demanding question posed from a hypothetical paradigm, answer it yourself (in the negative), and then infer there can be no other explanation other than what you insist upon … all in the absence of empirical data of relevance in the first place, ie: in this case, the presence of said organics on Mars!

What hypothetical paradigm is that? There is plenty of evidence that complex organic molecules are found in comets and a whole class of meteoritic material, and that those are of extraterrestrial origin dating back billions of years. This is also consistent with evidence of complex hydrocarbons detected in interstellar dust clouds. I'm just connecting the dots here.



My point is that the hypothesis is presently being put to the test, by the geological detailed exploration of an impact crater on Mars, where the hypothesis predicts the presence of organics .. and so far, no 'complex organics' (of bio-significance) have been identified.

What hypothesis is that? There are many hypotheses making different predictions about where exactly we might find organics on Mars.



Do we know how long the surface materials of that comet were exposed to radiation? How long would that be, compared with Mars' case/incident intensities? How do we know this?

The materials detected by Star dust come from deep inside the comet.


Why is it a statistical improbability? Please demonstrate excluding speculative hypotheses.
Because Earth and Mars are located in the same part of the solar system subjected to the same general space environment for billions of years.



(Please include: that there were no complex organics found in the returned moon rock samples (also presumably including hypothetical meteoric ancestry), and terrestrially sourced Lunar meteorite samples).

Unlike Earth and Mars, there are no known mechanisms (except ice) on the Moon that could preserve, distribute and concentrate organic materials on the surface. Where we might find them is inside the ice deposits at the poles. I say we should follow the ice. Ice and complex organics seem to go together for a number of different reasons.

Colin Robinson
2013-May-25, 01:29 AM
Why is it a statistical improbability? Please demonstrate excluding speculative hypotheses. (Please include: that there were no complex organics found in the returned moon rock samples (also presumably including hypothetical meteoric ancestry), and terrestrially sourced Lunar meteorite samples).

Actually samples taken from the lunar surface by the Apollo missions do contain low but measurable concentrations of quite complex organic molecules, such as benzene. See Organic analysis of lunar samples (http://www.ncbi.nlm.nih.gov/pubmed/11998860)

I think that's one reason why scientists were surprised by the results of mass spectrometer experiment of the Viking mission to Mars. It seemed to show nil organics in the sample. Although it did register a trace of organo-chlorine compounds which were interpreted as contaminants from Earth.

Selfsim
2013-May-25, 02:58 AM
Actually samples taken from the lunar surface by the Apollo missions do contain low but measurable concentrations of quite complex organic molecules, such as benzene. See Organic analysis of lunar samples (http://www.ncbi.nlm.nih.gov/pubmed/11998860)

I think that's one reason why scientists were surprised by the results of mass spectrometer experiment of the Viking mission to Mars. It seemed to show nil organics in the sample. Although it did register a trace of organo-chlorine compounds which were interpreted as contaminants from Earth.Spacecraft exhaust by-product contamination (http://www.lpi.usra.edu/meetings/LEA/presentations/tues_pm/Dworkin.pdf) (? .. methinks) … (Slide 7)

Thrusters used mixtures of hydrazine N2H4, methyl-hydrazine (CH3)nN2H2 and nitrogen tetroxide N2O4. The byproducts will thus contain compounds of NH3, H2O, CO, NO, O2, CO2, NO2 and trace organics.

Selfsim
2013-May-25, 03:20 AM
… I'm just connecting the dots here.... And that's the point.
Dots can be connected lotsa ways and the end result is intended as a potential explanation. Explanations are not intended as a substitute for empirical physical reality. (Groan! … This conversation is about to go 'all metaphysical' … (.. groan .. yet again) ).

What hypothesis is that? There are many hypotheses making different predictions about where exactly we might find organics on Mars.Take your pick … it doesn't really matter which one you choose ... the point is that they are all hypotheses.

The materials detected by Star dust come from deep inside the comet.References?

Because Earth and Mars are located in the same part of the solar system subjected to the same general space environment for billions of years.How do you know the distribution of organics within that parent population of potential meteorites, with sufficient accuracy to substantiate your claims?

Anyway, even a likely occurrence (or a statistical improbability) does not result in a dead certainty.

Unlike Earth and Mars, there are no known mechanisms (except ice) on the Moon that could preserve, distribute and concentrate organic materials on the surface. Where we might find them is inside the ice deposits at the poles. I say we should follow the ice. Ice and complex organics seem to go together for a number of different reasons.I say we should follow the Apollo landing sites (which were contaminated).

The point is, you keep making these bold claims on a reality that you have created from hypotheses. Have you forgotten that the bases you make these claims from are speculative hypotheses .. not physical reality?

Colin Robinson
2013-May-25, 03:27 AM
Spacecraft exhaust by-product contamination (http://www.lpi.usra.edu/meetings/LEA/presentations/tues_pm/Dworkin.pdf) (? .. methinks) … (Slide 7)

Thrusters used mixtures of hydrazine N2H4, methyl-hydrazine (CH3)nN2H2 and nitrogen tetroxide N2O4. The byproducts will thus contain compounds of NH3, H2O, CO, NO, O2, CO2, NO2 and trace organics.

"The recent detection of organic signatures on the Moon by Chandrayaan-1 supports the long-held belief that organic molecules are delivered to the surface of the Moon by impact processes (comets, asteroids and meteorites)."

Organic Molecules on the Moon (Lunar Science Forum 2011) (http://lunarscience2011.arc.nasa.gov/organic-molecules-moon.html)

Selfsim
2013-May-25, 03:52 AM
"The recent detection of organic signatures on the Moon by Chandrayaan-1 supports the long-held belief that organic molecules are delivered to the surface of the Moon by impact processes (comets, asteroids and meteorites)."

Organic Molecules on the Moon (Lunar Science Forum 2011) (http://lunarscience2011.arc.nasa.gov/organic-molecules-moon.html)Link to the paper/presentation, please?

Anyway: "The recent detection of organic signatures on the Moon by Chandrayaan-1 supports the long-held belief …"

I have lots of 'long-held beliefs' … and if I really try hard, I can find lots of 'evidence' in support of them. But does that affect measurable physical reality?

Colin Robinson
2013-May-25, 04:27 AM
Link to the paper/presentation, please?

When I have time I will look for that.


Anyway: "The recent detection of organic signatures on the Moon by Chandrayaan-1 supports the long-held belief …"

I have lots of 'long-held beliefs' … and if I really try hard, I can find lots of 'evidence' in support of them. But does that affect measurable physical reality?

"Measurable physical reality" is exactly what missions such as Chandrayaan-1 collect raw data about. However, no amount of raw data is going to tell you by itself how organic molecules got to the moon.

The idea that organics were brought there by smaller objects — asteroids, comets etc — is consistent with what's known about composition of the smaller objects (some of them do contain organic molecules), and with how scientists think the Moon got all its craters (by smaller objects colliding with it).

It is true that many things about the solar system remain unknown. It is conceivable that all reports of organics on the Moon are actually due to contamination by our own space missions, and/or misinterpreted data etc. It is also conceivable that if there are organics on the Moon, they didn't get there by smaller objects colliding, but some other way. If you have a better theory, Selfsim, let's hear it.

Selfsim
2013-May-25, 08:17 AM
Hmm ... interesting .. I found this report ...

INVESTIGATING THE ORIGIN OF CHLOROHYDROCARBONS DETECTED BY THE SAMPLE ANALYSIS AT MARS (SAM) INSTRUMENT AT ROCKNEST. (http://www.lpi.usra.edu/meetings/lpsc2013/pdf/1080.pdf)

The Sample Analysis at Mars (SAM) instrument suite on MSL analyzed the organic composition of the soil at Rocknest in Gale Crater using a combination of pyrolysis evolved gas analysis (EGA) and GCMS. One empty cup procedural blank followed by multiple EGA-GCMS analyses of the Rocknest soil were carried out.
...
Terrestrial N-methyl-N-(t-butyldimethylsilyl)trifluoro-acetamide (MTBSTFA) and associated reaction products from the SAM wet chemistry experiment were identified in both the blank and soil EGA-GCMS analyses. Based on laboratory pyrolysis GCMS experiments, combustion of MTBSTFA during SAM pyrolysis and reaction with martian Cl can explain the presence of the chloromethanes and a chloromethyl-propene also detected by SAM. Furthermore, these are the two chlorohydrocarbon classes expected by MTBSTFA combustion. Thus, at this time, while MTBSTFA contamination can explain all of the chlorohydrocarbons observed, we cannot exclude the possibility that traces of martian organics contributed to the chloromethanes measured by SAM.First time I've heard that they can explain all of the (di)chloromethane(s) observed, courtesy of a terrestrial contaminant. And, it seems that it came from the wet chemistry front-end!

Should be interesting to see how the Cumberland testing goes ...

Don J
2013-May-25, 08:24 PM
Hmm ... interesting .. I found this report ...
.....
Thus, at this time, while MTBSTFA contamination can explain all of the chlorohydrocarbons observed, we cannot exclude the possibility that traces of martian organics contributed to the chloromethanes measured by SAM

INVESTIGATING THE ORIGIN OF CHLOROHYDROCARBONS DETECTED BY THE SAMPLE ANALYSIS AT MARS (SAM) INSTRUMENT AT ROCKNEST. (http://www.lpi.usra.edu/meetings/lpsc2013/pdf/1080.pdf)
First time I've heard that they can explain all of the (di)chloromethane(s) observed, courtesy of a terrestrial contaminant. And, it seems that it came from the wet chemistry front-end!

I see that they do not exclude that traces of Martian organics have contributed to the chloromethanes measured by SAM. It is also interesting to note that Curiosity have detected perchlorates in Gale crater.

http://www.sciencemag.org/content/340/6129/138.2.summary
Pesky Perchlorates All Over Mars

Curiosity rover has discovered perchlorates in equatorial Gale crater, implying that they carpet the martian surface and explaining why the rover stumbled in its first search for organic traces of ancient martian life.
Also if you read the PDF page 2 -Discussion- option (3)
http://www.lpi.usra.edu/meetings/lpsc2013/pdf/1080.pdf
reaction of Martian soil CI with Martian organics during pyroliysis and/or Martian chlorohydrocarbons in the soil . You will notice that it is said that the lack of chlorohydrocarbons detected in the SAM procedural blank run indicates that the chlorohydrocarbons themselve are not contaminants from the SAM instrument.

Do you know if other chlorinated aromatic molecules were detected by SAM instrument?
I ask this because of that comment made by Klaus Biemann, leader for the Viking GC-MS experiment about the Navarro-Gonzalez and McKay paper on perchlorate issue when heated at -(200 celsius+)- with organics:
http://www.astrobio.net/exclusive/4928/curiosity%E2%80%99s-search-for-organics


Klaus Biemann, leader for the Viking GC-MS experiment, has sharply criticized the perchlorate theory. In a published comment on the Navarro-Gonzalez and McKay paper, he and Jeffrey Bada of the Scripps Institution wrote that the theory is based on faulty data and unfounded extrapolations, and that it ignores the known presence of several cleaning compounds found in the GC-MS during the Viking experiments. They also contend that if the process described by McKay and Navarro-Gonzalez had taken place, that other compounds – in this case other chlorinated aromatic molecules – would also be produced on Mars

Selfsim
2013-May-26, 01:31 AM
I see that they do not exclude that traces of Martian organics have contributed to the chloromethanes measured by SAM. It is also interesting to note that Curiosity have detected perchlorates in Gale crater.

http://www.sciencemag.org/content/340/6129/138.2.summary
Pesky Perchlorates All Over Mars

Also if you read the PDF page 2 -Discussion- option (3)
http://www.lpi.usra.edu/meetings/lpsc2013/pdf/1080.pdf
reaction of Martian soil CI with Martian organics during pyroliysis and/or Martian chlorohydrocarbons in the soil . You will notice that it is said that the lack of chlorohydrocarbons detected in the SAM procedural blank run indicates that the chlorohydrocarbons themselve are not contaminants from the SAM instrument.Yep .. I wasn't necessarily trying to make a point against that particular speculative possibility. The point worthy of note is that the proportion of the products, is accounted for entirely by the known amount of terrestrial 'contaminant' (MTBSTFA) .. which means there's another hypothesis which accounts entirely for the (di)chloromethane products (which are also partially formed by the Cl- ions from the confirmed martian perchlorates .. which someone said somewhere in all these quotes, (Mahaffy?), were definitely 'of martian origin', although, I don't believe that SAM can detect Cl isotope ratios .. so I don't know on which/what basis he can say that(??)

I'm not actually certain it should be a called a 'contaminant', either, (this issue is pretty tricky, because of the way the report is written). AIUI, the MTBSTFA is an organic solvent and is deliberately combined with the soil sample in a metal cup wet chemical analysis). But the process described for Rocknest is EGA/GCMS analysis, which doesn't make use of the MTBSTFA, and uses a completely separate quartz cup. (The idea is that the 'wet' process preserves large polar and temperature sensitive organic molecules so that the GCMS can subsequently detect them(if present).

Before making any assertions about any of these 'hypotheses, I think intimate knowledge of how the tests were performed, and how SAM performs them, is needed. How they are performed on each particular occasion, (ie: what steps are taken), I think, is decided by the SAM analysis team prior to the test, and is based on the target they're going after … (we don't have that information …).

Its pretty tricky, eh?


Do you know if other chlorinated aromatic molecules were detected by SAM instrument?
I ask this because of that comment made by Klaus Biemann, leader for the Viking GC-MS experiment about the Navarro-Gonzalez and McKay paper on perchlorate issue when heated at -(200 celsius+)- with organics:
http://www.astrobio.net/exclusive/4928/curiosity%E2%80%99s-search-for-organicsAt the moment, all I know is what is in this Glavin (et al) report, (Rocknest analysis). In it, they also show the peaks associated with choloroform (CHCl3.)

Frankly, I get a feeling that the instrument sensitivity is so great, that it may now be out of synch with how the decontamination process has been done. Ie: the present process would make assumptions about where to apply cleaning solutions (and in what concentrations). It may not be so concerned about the residuals it leaves behind (and where they're left), and how this may effect the ultimate chemistry measurements, however(??) For instance, they seem to reply on shaking dirt (aka 'scrubbed'), in the 'Sample Handling and Acquisition System', (CHIMRA), as a way of getting rid of residual cleaning products …. does that sound like a solid, reliable process leading to consistent replication of test results, to you(?) Maybe the 'empty' control sample result isn't necessarily consistently repeatable (? .. I dunno …)

Don J
2013-May-26, 02:22 AM
Before making any assertions about any of these 'hypotheses, I think intimate knowledge of how the tests were performed, and how SAM performs them, is needed. How they are performed on each particular occasion, (ie: what steps are taken), I think, is decided by the SAM analysis team prior to the test, and is based on the target they're going after … (we don't have that information …).

Its pretty tricky, eh?

I agree on that.


But the process described for Rocknest is EGA/GCMS analysis, which doesn't make use of the MTBSTFA, and uses a completely separate quartz cup. (The idea is that the 'wet' process preserves large polar and temperature sensitive organic molecules so that the GCMS can subsequently detect them(if present).

All the sample checked by SAM were heated in the oven used by the SAM GCMS so that mean that the wet process was not used.See page 2 table 1 comparaison of the abondance of chloromethane detected by the Viking and SAM GCMS for the temperature range .



At the moment, all I know is what is in this Glavin (et al) report, (Rocknest analysis). In it, they also show the peaks associated with choloroform (CHCl3.)

Thanks!I have noticed the (CHCl3)peak but did not know the chemical name of it.


Frankly, I get a feeling that the instrument sensitivity is so great,...

...That it detected another chlorinated aromatic molecules....trichloromethane (CHCl3)
chloroform (CHCl3), also called trichloromethane,
http://www.britannica.com/EBchecked/topic/113697/chloroform-CHCl3

Maybe that the trichloromethane (CHCl3)is the other chlorinated aromatic molecules Klaus Biemann, leader for the Viking GC-MS experiment and Jeffrey Bada of the Scripps Institution talked about:
"They also contend that if the process described by McKay and Navarro-Gonzalez had taken place, that other compounds – in this case other chlorinated aromatic molecules – would also be produced on Mars"

Selfsim
2013-May-26, 03:21 AM
I agree on that.:)


All the sample checked by SAM were heated in the GCMS so that mean that the wet process was not used. See page 2 table 1 comparaison of the abondance of chloromethane detected by the Viking and SAM GCMS Not necessarily, (apparently).
It seems that the Wet Chemistry analysis process heats the wetted sample to ~350C in one of the SAM ovens. It captures the evolved hydrocarbons, and then feeds them to the GCMS for analysis.
The EGA process however, calls for heating the sample as a first step to ~950 to 1100C.
So, I think the difference between the two processes (apart from the wetting of the sample), is the difference in the temperatures the sample oven is directed to heat up to.

GCMS is apparently (now) sensitive enough, to analyse the gases evaporated from the wet sample even when they are only heated to ~350C. This is how they avoid combustion, I think. Table 1 infers that the temperature for the three samples went up to 533C, 425C and 822C .. so, I think you're right, in that it seems that they used the higher temperature EGA process for the Rocknest sample. If this is correct, then where did the MTBSTFA come from? (Ie: it shouldn't have been involved in the exercise at all! Perhaps this is why they called it a contaminant'(?) )


...That it detected another chlorinated aromatic molecules....trichloromethane (CHCl3)
chloroform (CHCl3), also called trichloromethane,
http://www.britannica.com/EBchecked/topic/113697/chloroform-CHCl3Hmm .. maybe .. the concentration is so low, its almost negligible, though(??) But it does show that none was detected in VL1 or VL2!


Maybe that the trichloromethane (CHCl3)is the other chlorinated aromatic molecules Klaus Biemann, leader for the Viking GC-MS experiment talked about:
"They also contend that if the process described by McKay and Navarro-Gonzalez had taken place, that other compounds – in this case other chlorinated aromatic molecules – would also be produced on Mars"Hmm .. maybe .. maybe not. It would have been adventurous of him to assert that CHCl3 should have been produced .. particularly when there was only <0.02 or 0.04 nmols of it produced in the SAM/Rocknest samples … almost the same amount as in the blank sample (ie: its almost in the 'noise')! (That would have been some prediction, of something so tiny in volume, eh?)

Don J
2013-May-26, 04:29 AM
Don J wrote:
The SAM GCMS instrument sensitivity is so great...
That it detected another chlorinated aromatic molecules....trichloromethane (CHCl3)
chloroform (CHCl3), also called trichloromethane,

Hmm .. maybe .. the concentration is so low, its almost negligible, though(??) But it does show that none was detected in VL1 or VL2!

That is why i pointed out the defenitive superiority in sensitivity of the SAM GCMS compared to the Viking GCMS.
Eta
Do you notice that the sample at John Klein don't produce trichloromethane .Probably because that it is not the same analyse method utilised compared to the actual case. Notice also in the blank runs in the graph there is no indication of trichloromethane which is supposed to came from contaminants ie residual cleaning products
http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=5126



Hmm .. maybe .. maybe not. It would have been adventurous of him to assert that CHCl3 should have been produced .. particularly when there was only <0.02 or 0.04 nmols of it produced in the SAM/Rocknest samples … almost the same amount as in the blank sample (ie: its almost in the 'noise')! (That would have been some prediction, of something so tiny in volume, eh?)

Not only Klaus Biemann don't talk about the level expected but he is also vague about the -other chlorinated aromatic molecules-in question.


"He.... also contend that if the process described by McKay and Navarro-Gonzalez had taken place, that other compounds – in this case other chlorinated aromatic molecules – would also be produced on Mars"

Selfsim
2013-May-26, 07:25 AM
That is why i pointed out the defenitive superiority in sensitivity of the SAM GCMS compared to the Viking GCMS.Fair enough ... one of the lessons learned .. ontop of some 38 years of intervening technology improvements, too!

Eta
Do you notice that the sample at John Klein don't produce trichloromethane .Probably because that it is not the same analyse method utilised compared to the actual case. Notice also in the blank runs in the graph there is no indication of trichloromethane which is supposed to came from contaminants ie residual cleaning products
http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=5126Err .. <achem> ... methinks we need something a little more precise than a 'glossy' press release graph (which doesn't even have a scale on the y-axis! Remember we're dealing with minute concentrations of these products(??)
I'd like to see a paper on the Klein experiment and findings ... (of the same quality as the Rocknest one).


Not only Klaus Biemann don't talk about the level expected but he is also vague about the -other chlorinated aromatic molecules-in question.Well, no more vague than the other crowd is, when it comes to their loose usage of the term 'organics'! :)

Selfsim
2013-May-26, 09:08 AM
Just for the record, here's an interesting design document for MAHLI ...

Curiosity’s Mars Hand Lens Imager (MAHLI) Investigation (http://link.springer.com/content/pdf/10.1007%2Fs11214-012-9910-4.pdf)


Biogenicity:
The search for present or past life on Mars has been of interest for more than a century. Even the earliest discussions of microscopic imaging of Martian materials and the earliest efforts to identify candidate field sites centered on the question of Martian biology (Lederberg 1960; Swan and Sagan 1965; Soffen 1969). Although the primary objective of the MSL mission is the search for habitable environments, the very nature of habitability—the potential for an environment to support or sustain life—lends itself to the discussion of whether the MAHLI investigation might directly address the question of biogenicity.

Based on the results of the previous robotic missions that have flown past, orbited, and landed on Mars, the likelihood of detecting a biosignature in a MAHLI image seems to be remote. MAHLI images cannot resolve features of microbe size (typically 1–30 microns for most prokaryotic organisms). The smallest grains that can be resolved in the highest resolution MAHLI images are of the order of 45–60 μm in size. Moreover, being resolved does not mean being identifiable. MAHLI images could certainly resolve macroscopic groupings of micro-organisms (e.g., patches of crustose lichen on a rock) if they occur, but no such features have been found in MER MI or Phoenix Robotic Arm Camera (RAC) images already acquired on Mars. In order to be readily resolved by MAHLI, biosignatures, such as body fossils or evidence of sediment bioturbation, would have to occur at a scales>100 μm (Summons et al. 2011). Certain biofabrics—such as microbial laminae and composite microbial structures (e.g. stromatolites)—would certainly be detectable (Summons et al. 2011; Williams and Sumner 2012), although these are not without controversy, as abiogenic structures can mimic biofabric (e.g., McLoughlin et al. 2008).

Selfsim
2013-May-26, 09:38 AM
... And another snippet ...

NASA Curiosity Rover Team Selects Second Drilling Target on Mars (http://www.nasa.gov/home/hqnews/2013/may/HQ_13-136_Curiosity_Second_Mars_Sample.html)


... This second drilling is intended to confirm results from the first drilling, which indicated the chemistry of the first powdered sample from John Klein was much less oxidizing than that of a soil sample the rover scooped up before it began drilling.

"We know there is some cross-contamination from the previous sample each time," said Dawn Sumner, a long-term planner for Curiosity's science team at the University of California at Davis. "For the Cumberland sample, we expect to have most of that cross-contamination come from a similar rock, rather than from very different soil."

... So presumably, by the same logic, the residuals from the initial cleaning, (of the CHIMRA sample handling system), would have been expected to show up in the initial Rocknest soil drift sample ...(??) Whether the initial contaminants ever completely leave the system entirely, is another question yet again(?) ..

Paul Wally
2013-May-26, 11:04 PM
... And that's the point.
Dots can be connected lotsa ways and the end result is intended as a potential explanation. Explanations are not intended as a substitute for empirical physical reality. (Groan! … This conversation is about to go 'all metaphysical' … (.. groan .. yet again) ).

The data has to be interpreted in some logically coherent theoretical framework anyway and I'm talking about data from several independent sources (observational, experimental and mathematical modeling) coming together to form a coherent picture of reality. It's not just about data observed at one location. We have to look at the larger picture. What picture is emerging from all the data and all the research done over the decades? The synthesis and distribution of organic compounds in space is that emerging reality, and as more data comes in, our picture of that reality will only become clearer.


Take your pick … it doesn't really matter which one you choose ... the point is that they are all hypotheses.

I'm asking what hypothesis you're referring to, because what I'm presenting is not purely hypothetical but has an evidential and logical support structure.
It is an interpretation of what the evidence means, so it would help if you could pinpoint some particular elements and provide an alternative logically coherent interpretation. It's not just about data, data, data. At some point we have to ask ourselves what it all means - what it's telling us.


References?

There's a photograph of the jets of material coming through holes in the surface of comet wild-2.

Selfsim
2013-May-27, 07:04 AM
Y'know, Paul Wally, this time 'round I'm not particularly willing to go around the roundabout (for the umpteenth time), so this will be my last post on this side-topic.

From past discussions with you, because of a strongly held, philosophically based belief you have, you seem to choose to adopt hypothesis=>test=>data=>theory, as a substitute for something you envisage as 'reality'. That is your choice, but because of that strongly held opinion, you seem evidently unable to accept that this process is only intended to lead to a consistent 'explanation' for something, (which you then subsequently assert is reality). The 'explanations' afforded by science are always open to doubt and uncertainty, and there's usually more than one of them. They also change. This demonstrates that they are not some fixed, absolute reality, to be held as being true, purely by the application of philosophically based logic on top of hypothetical modelling.

Unambiguous, empirically sourced test results, once obtained however, remain replicable and don't change.

Your choice of wording below highlights that you have taken some of science's theories or hypotheses as reality:

.. coming together to form a coherent picture of reality.
...
The synthesis and distribution of organic compounds in space is that emerging reality, and as more data comes in, our picture of that reality will only become clearer.
...

I'm asking what hypothesis you're referring to, because what I'm presenting is not purely hypothetical but has an evidential and logical support structure.

It is an interpretation of what the evidence means, so it would help if you could pinpoint some particular elements and provide an alternative logically coherent interpretation. Complex organics has not yet been unambiguously 'declared' to have been found on Mars. Why such compounds haven't been found, is open to conjecture and discussion. There are several valid, speculative hypotheses under consideration, some of which have nothing to do with natural 'destruction' of organics which "must have landed on Mars in tact", (your words). Frankly I don't see any point in debating such speculation, especially in the light of the 'possibility' of simple experimental sample contamination, Viking's LR positive results, and a mere two Curiosity/SAM sites having been sampled so far! (Three including Cumberland .. whose results have not yet been announced).


It's not just about data, data, data. At some point we have to ask ourselves what it all means - what it's telling us... and accept the answer to that question as reality, eh?


There's a photograph of the jets of material coming through holes in the surface of comet wild-2.There are several different ideas about comet jet phenomena. I haven't seen any asserting that they emanate from anywhere other than the surface regions, or immediately exposed sub-layers .. ie: not from 'deep inside the comet'.

ASTRO BOY
2013-May-27, 09:27 AM
.. and accept the answer to that question as reality, eh?




Excuse me jumping in here but I do need to straighten that sentence out........

"Accepting that in all probability there is an answer, and the odds are that answer is with the affirmative position based on the limited data available"

Selfsim
2013-May-27, 10:17 AM
It's not just about data, data, data. At some point we have to ask ourselves what it all means - what it's telling us.

.. and accept the answer to that question as reality, eh?Excuse me jumping in here but I do need to straighten that sentence out........

"Accepting that in all probability there is an answer, and the odds are that answer is with the affirmative position based on the limited data available"
... and you see that as qualifying my question, eh?

Paul Wally
2013-May-27, 07:32 PM
Y'know, Paul Wally, this time 'round I'm not particularly willing to go around the roundabout (for the umpteenth time), so this will be my last post on this side-topic.

From past discussions with you, because of a strongly held, philosophically based belief you have, you seem to choose to adopt hypothesis=>test=>data=>theory, as a substitute for something you envisage as 'reality'. That is your choice, but because of that strongly held opinion, you seem evidently unable to accept that this process is only intended to lead to a consistent 'explanation' for something, (which you then subsequently assert is reality). The 'explanations' afforded by science are always open to doubt and uncertainty, and there's usually more than one of them. They also change. This demonstrates that they are not some fixed, absolute reality, to be held as being true, purely by the application of philosophically based logic on top of hypothetical modelling.


I said it's a picture of reality. That picture can of course be incomplete, but our picture of reality improves over time. Data on the other hand is not reality.
Tycho Brahe's measurements, as accurate as they were, were just data and not reality. Kepler then presented us with a view of the reality behind that data.


Unambiguous, empirically sourced test results, once obtained however, remain replicable and don't change.

Indeed.


Your choice of wording below highlights that you have taken some of science's theories or hypotheses as reality:

That's right, but that doesn't mean theories or hypotheses represent reality correctly, we may never know something like that. However, they are the means by which we represent reality to ourselves.



Complex organics has not yet been unambiguously 'declared' to have been found on Mars. Why such compounds haven't been found, is open to conjecture and discussion. There are several valid, speculative hypotheses under consideration, some of which have nothing to do with natural 'destruction' of organics which "must have landed on Mars in tact", (your words). Frankly I don't see any point in debating such speculation, especially in the light of the 'possibility' of simple experimental sample contamination, Viking's LR positive results, and a mere two Curiosity/SAM sites having been sampled so far! (Three including Cumberland .. whose results have not yet been announced).

So what if complex organics have not yet been 'declared' to exist on Mars? That doesn't mean they don't exist on Mars, nor does it mean that the ultimate aim is to find out whether or not they exist on Mars. In my opinion, the aim is simply to find them, with the eventual purpose of learning something from that finding about the possibility of life on Mars.



There are several different ideas about comet jet phenomena. I haven't seen any asserting that they emanate from anywhere other than the surface regions, or immediately exposed sub-layers .. ie: not from 'deep inside the comet'.

The jets shoot straight up from the surface at quite a high velocity, like a geyser. It doesn't make physical sense if they originate from on top of the surface. Surface volatiles would just evaporate in all directions instead of shooting up in a straight line. What is probably happening is that the comet consists of harder rocky material on the outside and ice inside internal cavities. When the comet is heated by the sun the harder surface heats up and conducts heat to the inside causing the volatiles to boil, building up pressure on the inside. The steam then tries to find a way through any cracks or fissures until it eventually shoots out through holes in the surface.

Selfsim
2013-May-28, 12:03 AM
Coming back to martian soil analysis, I found this paper about the Rocknest sample (blank run) analysis:

FROM BACKGROUND TO SIGNAL: CHALLENGES OF A SOLID SAMPLE ANALYSIS USING SAM GC-MS (http://www.lpi.usra.edu/meetings/lpsc2013/pdf/1249.pdf)

Lots of pertinent information in this one … some highlights are:

1) Major peaks have been identified, however, work is still ongoing to characterize all the ~30 peaks observed in the GCMS background and understand their origin;

2) Thus, aromatic compounds such as benzene and toluene, which are present in the GCMS blank signal but do not display a peak in the EGA, are likely to come from the traps and are suspected to be released from the Tenax TA.1. Aromatics such as ethylbenzene and xylene are suspected to be present in the blank signal, with no clear evidence about their origin. Other molecules present in the blank are H2O, CO2 and SO2, internal to the system. Also, column bleeding products are observed, resulting from the thermal degradation of the internal polysiloxane phase of the column;

3) Other major contributors to the background signal are the reaction products of one of the chemicals used for SAM wet chemistry experiment: N-methyl-N-tert- butyldimethylsilyl-trifluoroacetamide (MTBSTFA). This molecule was sealed inside each of the seven derivatization cups present in the SMS. Although none of them have been punctured yet for the actual wet chemistry experiment, it is suspected that one or more may be releasing some of its reactant. Any MTBSTFA present inside the SMS would readily react with the water present to form monosilylated water, bisilylated water and a trifluoro-N-acetamide byproduct (Fig. 2). Those 3 compounds were identified in the GCMS blank by their mass spectra.
...
… the presence of such a background has numerous implications for the solid sample analysis:

(1) It can make uncertain any detection of a compound also present in the background and make difficult to confirm a detection of a molecule present at a concentration lower than the background level.
...
(2) It interferes with the analysis of trace levels of molecules, by overlapping peaks. Thus, lowering the effect of background in general, and MTBSTFA in particular, would significantly improve the signal to noise ratio, and strategies are under investigation in this purpose (cold sample drop off, He flush of the SMS, low temperature sample heating prior to higher temperature EGA analysis).
...
(3) The presence of reactive species in the background can create newly formed products by interaction with suspected Martian molecules, for instance perchlorates. Before claiming detection of Martian molecules, it has to be ruled out that these compounds can not come from reaction with internal molecules.
...
(4) Residual molecules in SAM can also contribute to combustion into CO2 and have a role in the isotope ratio changes. For all these reasons, the initial abundance of MTBSTFA has been extrapolated and its contribution to the total background is determined to be from 30 to 55 nmoles.
...
Moreover, another contributor to the background signal could be the scoop to CHIMRA sampling chain, which the Rocknest sample went through before being delivered to SAM (not used in the blank run). However, intensive cleaning and monitoring of sampling chain makes this possible source of organics to SAM for the first delivery unlikely.

30 to 55 nmoles is a lot compared with the 0.04 to 2.4 nmols of the organic compounds of CH2Cl2 (dichloromethane) and CH3C (chloromethane) .. and also compared with any with low concentrations of any 'possible' complex organics which might exist in the soil .. (eg: the Antarctic analogue?)


Footnote:
1. 'Tenax TA' is a porous polymer resin used in the hydrocarbon trap prior to the GCMS.


PS: With such issues to deal with, I wouldn't be expecting instantaneous GCMS or QMS results, following any sample testing .. (like Cumberland), unfortunately. Perhaps this is why its so hard to find any details on the Klein results, also(?)
Maybe as the system acquires some more 'martian grunge', the contaminant effects will become less significant over time. If the MTBSTFA cups are leaking though, their effectiveness in the process of avoiding soil organics oxidation during the heating phase, is diminished also .. which is very unfortunate.
I'll bet Levin is disappointed … and living in hope for some better luck to turn up sometime! .. (where are those MAHLI photos of green algae on some Gale crater rocks? Personally, I think the chunk of plastic originally found, (http://cosmoquest.org/forum/showthread.php?138665-Curiosity-Finds%85SOMETHING%85on-Martian-Surface&p=2070467#post2070467) would have been better interpreted as a prawn or shrimp shell … :) )

ASTRO BOY
2013-May-28, 03:51 AM
I'll bet Levin is disappointed … and living in hope for some better luck to turn up sometime! .. (where are those MAHLI photos of green algae on some Gale crater rocks? Personally, I think the chunk of plastic originally found, (http://cosmoquest.org/forum/showthread.php?138665-Curiosity-Finds%85SOMETHING%85on-Martian-Surface&p=2070467#post2070467) would have been better interpreted as a prawn or shrimp shell … :) )


Why are your posts so full of derision and facetiousness?
He may have believed what he thought he found and he maybe wrong, but what will your position be if some irrefutable evidence of life is found? It's easy to be wise after the event.
Scientists have been making mistakes/claims for eons...It's all part of the game.
But it's by mistakes we learn and progress.


I also found your link interesting and the first post particularly......thus....

""Looks like some kind of shrimp (or prawn) shell ...

... ""Just wait until the Life in Space Forum folk hear about this one!""



I don't really know, but was it ever taken up in the LiS forum?...I never saw it if it was.
My point again is the obvious derision and facetiousness that seem to highlight your posts....sad.

Selfsim
2013-May-28, 06:53 AM
.. And then, from the same, 44th Planetary Science Conference ...

DETECTION OF ORGANIC CONSTITUENTS INCLUDING CHLOROMETHYLPROPENE IN THE ANALYSES OF THE ROCKNEST DRIFT BY SAMPLE ANALYSIS AT MARS (SAM). (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011130_2013010697.pdf)

Some notable quotes ..


1) Rocknest was chosen as the first solid sample site because it was believed to be broadly similar to aeolian sand/dust deposits studied by MER, and because this material was ideal for decontamination of the Sample Acquisition/Sample Processing and Handling (SA/SPaH) hardware . Although wind-transported surface sediments provide poor conditions for organic matter preservation, they do not preclude the presence of recent meteoritic organic material.

2) Notably, a variety of other masses (Fig. 1) from organic molecules were detected in the Rocknest samples, but were largely near or below detection limits and showed a different thermal profile in the blank. The blank data cannot account for all of the organic signatures observed in the Rocknest sample. However, a similar set of masses with the same evolution character as the Rocknest sample were detected in lab EGA experiments analyzing fused silica with 1 wt% MgCl2O8 <magnesium perchlorate> and MTBSTFA (not shown).

3) Four compounds were identified in the Rocknest GCMS data that are not in the blank: mono-, di-, and tri-chloromethanes and chloromethylpropene (a C4 chlorinated hydrocarbon).

4) The disparity in the EGA and GCMS observations for organics detected in Rocknest data that are not explained by the blank may be indicating that gases are condensing, ineffectively trapping, unstable, or are simply not amenable to passage through the GC.

5) It is possible that a portion of the organic signatures observed in the Rocknest data are from indigenous martian organic matter. However, if it is present, it is in concentrations lower than the current SAM background and will be difficult to confirm.

6) SAM has made no definitive detection of organic materials indigenous to the Rocknest sample.

Selfsim
2013-May-28, 06:54 AM
The questions remaining for me are:

1) "Could a reaction between the Viking LR soil samples, and any terrestrial contaminants present, and the labelled nutrients added, have resulted in a false positive reading of apparently evolved carbon isotopes?"

2) "Is there something to learn from the SAM GCMS/QMS results, which may be of relevance in the analysis of the Viking LR tests?"

The measurement of isotopes is clearly impacted at present in the SAM sample-to-QMS chain, (by its contaminant and its associated by-products). Might this also have happened in Viking's LR isotope counting technology?

Paul Wally
2013-May-29, 12:17 PM
The questions remaining for me are:

1) "Could a reaction between the Viking LR soil samples, and any terrestrial contaminants present, and the labelled nutrients added, have resulted in a false positive reading of apparently evolved carbon isotopes?"

2) "Is there something to learn from the SAM GCMS/QMS results, which may be of relevance in the analysis of the Viking LR tests?"

The measurement of isotopes is clearly impacted at present in the SAM sample-to-QMS chain, (by its contaminant and its associated by-products). Might this also have happened in Viking's LR isotope counting technology?

Oh, there are many more questions. This is just the beginning (not the end) of the search for organics on Mars. What I would conclude from the results of the first drill sample test is that if there were organics within the sample, then they were at such low concentrations that "terrestrial contaminants" became an issue. So whether the carbon is there or not, the fact remains that there's not enough of it in the sample anyway.

Now since the aim is to actually find complex organic compounds on Mars, the natural question would be why there are such low concentrations of organics at that particular location. The answer to that question might help in the identification possible future locations where the levels of carbon or carbon containing organics is expected to be sufficiently above any background levels or "terrestrial contaminants" so as to give unambiguous results.Thus, I don't quite see the importance of your question #2 at this stage. It seems you want to study one ambiguous result in order to understand another ambiguous result from 40 years ago.

Seaumas
2013-May-30, 12:26 AM
Lets send them up some Miracle Grow. Its the best.

neilzero
2013-May-30, 02:55 AM
I would think that only rare comet jets come "straight up" from the surface = most of them are tilted about a radian from the local surface and almost a radian from the average surface = most comet nuclei are not even close to spherical. A local surface averages 10 square meters and is irregular in shape? Since the nuclei has almost no gravity, a jet from several meters below the surface will find a torturous path of least resistance = not along the zenith from the mass center. Neil

Selfsim
2013-May-30, 08:50 AM
What I would conclude from the results of the first drill sample test is that if there were organics within the sample, then they were at such low concentrations that "terrestrial contaminants" became an issue. So whether the carbon is there or not, the fact remains that there's not enough of it in the sample anyway. Do you mean 'enough' to be detected?


Now since the aim is to actually find complex organic compounds on Mars, ...Since when was this a mission goal of Curiosity, Phoenix or Viking?


...the natural question would be why there are such low concentrations of organics at that particular location. The answer to that question might help in the identification possible future locations where the levels of carbon or carbon containing organics is expected to be sufficiently above any background levels or "terrestrial contaminants" so as to give unambiguous resultsNavaro-Gonzales' etal reinterpretation of the Viking results suggests:

≤0.1% perchlorate and 1.5 – 6.5 ppm organic carbon at Viking landing site 1 and

≤0.1% perchlorate and 0.7 – 2.6 ppm organic carbon at Viking landing site 2.

I'd say from those levels, and Curiosity's SAM/GCMS/EGA Rocknest drift sample result, (which admittedly includes the contamination factor), there is nothing particularly 'low' about the concentration of organics within Curiosity's locale.

If it is now seen as unexpectedly 'low' there, then clearly the original assumptions predicting what it 'should' be, are in need of revision.

Oh, and just for comparison, the Chilean Atacama desert sample used in the 2010 Viking re-evaluation study (Navaro-Gonzales etal) contained 32 +/- 6ppm organic carbon ... and that sample included terrestrial bio-organics.


Thus, I don't quite see the importance of your question #2 at this stage. It seems you want to study one ambiguous result in order to understand another ambiguous result from 40 years ago.Oh its not 'important' (whatever that means ..). It just arose from the conversation with Don J. See, the Viking LR experiment seems to now be regarded, (by some), as being a valid unambiguous test when viewed in isolation from the other Viking life tests (GEX, PR and GCMS). I'm just querying whether its detector might have somehow acquired a similar kind of contamination as Curiosity's(?) It seems that the venting and helium purge techniques may not get rid of all past contaminants from the sensitive detectors (QMS/GCMS columns, etc), so perhaps accumulated contaminents might somehow also account for some of the isotope curves they got(?? I dunno ..)

Paul Wally
2013-May-30, 07:26 PM
What I would conclude from the results of the first drill sample test is that if there were organics within the sample, then they were at such low concentrations that "terrestrial contaminants" became an issue. So whether the carbon is there or not, the fact remains that there's not enough of it in the sample anyway. Do you mean 'enough' to be detected?

I mean there is not sufficient concentrations to be unambiguously detectable. SAM does have the capability to unambiguously detect organic compounds if they are sufficiently above background levels.


Since when was this a mission goal of Curiosity, Phoenix or Viking?

Why would Curiosity have instruments designed specifically to detect and characterize various organic compounds if it was not a key mission goal?


Navaro-Gonzales' etal reinterpretation of the Viking results suggests:

≤0.1% perchlorate and 1.5 – 6.5 ppm organic carbon at Viking landing site 1 and

≤0.1% perchlorate and 0.7 – 2.6 ppm organic carbon at Viking landing site 2.

That's their reinterpretation and not a conclusive fact. You know very well there are multiple interpretations.



I'd say from those levels, and Curiosity's SAM/GCMS/EGA Rocknest drift sample result, (which admittedly includes the contamination factor), there is nothing particularly 'low' about the concentration of organics within Curiosity's locale.

As long as it's below or close to normal background levels, I consider it to be low.


If it is now seen as unexpectedly 'low' there, then clearly the original assumptions predicting what it 'should' be, are in need of revision.

Where it should be is where it is preserved for billions of years. The point is to find places where a rich variety of complex organics could have been concentrated and preserved for billions of years, and that requires a study of the geological history of the area. It's about following clues not just gathering random bits of data in a lackluster kind of way. The Cumberland results might prove conclusively whether the John Klein result was terrestrial contamination or Martian. In that case there will be another valuable clue to follow up.



Oh its not 'important' (whatever that means ..). It just arose from the conversation with Don J. See, the Viking LR experiment seems to now be regarded, (by some), as being a valid unambiguous test when viewed in isolation from the other Viking life tests (GEX, PR and GCMS). I'm just querying whether its detector might have somehow acquired a similar kind of contamination as Curiosity's(?) It seems that the venting and helium purge techniques may not get rid of all past contaminants from the sensitive detectors (QMS/GCMS columns, etc), so perhaps accumulated contaminents might somehow also account for some of the isotope curves they got(?? I dunno ..)

These so called "contaminants" is a relatively minor issue which you are blowing out of proportion. It's only relevant if you a priori assume that Curiosity is inherently incapable of unambiguously detecting complex organic molecules because of that. I suspect that you assume the latter.

Selfsim
2013-May-30, 10:23 PM
I mean there is not sufficient concentrations to be unambiguously detectable. SAM does have the capability to unambiguously detect organic compounds if they are sufficiently above background levels.The MTBSTFA contaminant may be due to a continuous leak, or it may have been a 'one-off' leak, intermittent leak, etc, etc. It wasn't planned. Its effects may not only be on the stability of successive (comparative) results, but it might also impact the long term viability of the wet chemistry front-end to GCMS/TLS/QMS. If this is so, then the ability to detect certain organic compounds will also be impaired - there are only 9 hermetically sealed ('leaking') cups containing the organic solvents. They are not re-usable.

Having said this, the impact of this 'leak', is yet another hypothesis, even though MTBSTFA was detected in the mass spectrum.


Now since the aim is to actually find complex organic compounds on Mars, …
Since when was this a mission goal of Curiosity, Phoenix or Viking?Why would Curiosity have instruments designed specifically to detect and characterize various organic compounds if it was not a key mission goal? Take a look at the mission goals and objectives. (http://en.wikipedia.org/wiki/Mars_Curiosity#Goals_and_objectives)
There is nothing there which says that Curiosity's goal is to find complex organics! (Which is what you originally stated). It is clearly there to characterise what it does find. There is a big difference between searching for something that may not be present, (in significant quantities), and characterising what is present.
This is the lesson learned from the mistakes of the Viking life detection mission which permeates all subsequent mars mission goal strategies.
The OP 'mars soil veggie patch' article shows that Phoenix was only able to detect the inorganic perchlorate, basic nutrients and pH levels of the soil .. not that there was organics in the soil!


That's their reinterpretation and not a conclusive fact. You know very well there are multiple interpretations.The figures were derived from a kinematic model based on the terrestrial GCMS and LR data sampling. It interesting that now you see such information as 'their interpretation' ie: not physical reality.
It seems you are now arguing my persistent point about the non-(physical) reality of theoretical models). Good to see!


As long as it's below or close to normal background levels, I consider it to be low.I agree with the relative comparison. Anything which excludes terrestrially sourced data in its natural environment, might be an appropriate precautionary stance, when exploring another planet, wouldn't you say?


Where it should be is where it is preserved for billions of years. The point is to find places where a rich variety of complex organics could have been concentrated and preserved for billions of years, and that requires a study of the geological history of the area. It's about following clues not just gathering random bits of data in a lackluster kind of way. The Cumberland results might prove conclusively whether the John Klein result was terrestrial contamination or Martian. In that case there will be another valuable clue to follow up.Actually details of the John Klein results have eluded all my searches!
(I'm starting to dream up conspiracies of deliberate suppression of the SAM results at the Klein drilling site! (… Oh no ..!.. :) ))
The contamination issue existed at the Rocknest drift scoop, which occurred before the Klein drill. It would have been interesting to see whether the MTBSTFA levels at Klein had changed (or not). I'm eager to see any SAM results for Cumberland .. (I hope they are more easily findable than the Klein details).


These so called "contaminants" is a relatively minor issue which you are blowing out of proportion. It's only relevant if you a priori assume that Curiosity is inherently incapable of unambiguously detecting complex organic molecules because of that. I suspect that you assume the latter.Not so. The clever analysis of the wet chemistry front-end, and a combination of TLS, QMS and GCMS including blank run data runs, could potentially sort out the problem. They haven't done all of these experiments on the same sample yet, though. Until they do that, and if the contamination is persistent, the issue will effect the results in so far as distinguishing what's going on.

Selfsim
2013-May-31, 08:01 AM
Take a look at the mission goals and objectives. (http://en.wikipedia.org/wiki/Mars_Curiosity#Goals_and_objectives)
There is nothing there which says that Curiosity's goal is to find complex organics! (Which is what you originally stated). It is clearly there to characterise what it does find. There is a big difference between searching for something that may not be present, (in significant quantities), and characterising what is present.
This is the lesson learned from the mistakes of the Viking life detection mission which permeates all subsequent mars mission goal strategies.Y'know I've done some checking on this point, and whilst I maintain that there is no published goal for Curiosity to find complex organics, I do agree that this does seem to be the basis on which Grotzinger and Vasavada are now directing operations. It seems that because Curiosity has been declared as having fulfilled its primary goal of finding a past environment with conditions conducive for life, they've taken it upon themselves to set the other goal:
Curiosity tasked with hunting for elusive Martian organic (dated May 27): (http://www.spaceflightnow.com/mars/msl/130527organics/#.Uag2N9i8Cho)

Grotzinger and Vasavada have directed their science team to develop a systematic search for organic molecules, driving the rover to locations thought to best sustain carbon. Curiosity is not equipped to find extant life, but there is much to learn about the red planet's ability to preserve organics and how to uncover them.

It won't be easy, Grotzinger said.

"I just think we'd be nuts to go around promising people that we have even a good chance of finding organics," Grotzinger said in April. "On the other hand, I think, as a mission, we have to undertake this search systematically, so that if we don't find anything, we can do a proper post-mortem and say here's what we tried, here's what we discovered, and here's our best attempt to explain why we might have failed."

And if scientists are lucky, the rover could make a discovery, he said.This is an interesting article ... they're now saying that Sharp may not have been the right place to look for evidence of past life!! ...

When NASA selected the Curiosity landing site, the prevailing theory was Mount Sharp was formed in a long-gone lake. But new research from scientists at Princeton University and the California Institute of Technology suggests Mount Sharp was assembled over eons by silt lifted into the Martian sky by winds.
The theory of wind formation for Mount Sharp would throw into doubt whether Mount Sharp is the best spot on Mars for a rover to seek evidence for past life, according to Kevin Lewis, a Princeton associate research scholar in geosciences and a participating scientist on the Curiosity rover mission. ... I also recognise that they are also looking for reasons to account for a deficit of organics .. (even after only two samples taken!)..


Vasavada said there should be many more carbon compounds than what Curiosity has discovered to date ...Hmm .. just sounds like a 'low-ball' to the public, in order to set expectations on the low side as far as finding significant complex organics.

All of which raises the question of the validity of the Viking LR results, the 'asteroids delivering abundant organics' and, if one sticks with this hypothesis, one has no choice other than to elevate the 'destruction' of organics' hypotheses, (as indicated by Vasavada's and Meyer's comments in the article), and of present sub-surface organics hypotheses.

I really do not understand why they are sticking so closely to the 'asteroid delivery of complex organics' hypothesis, however(??)

Why should the formation of abundant complex organics be thought of as not being 'likely', on a past (pre-biotic) Earth?
Why do they need asteroid delivery to be the primary source, (as is evidenced by the mars team's expectation of finding evidence for it on Mars)?

(Perhaps I'll start a new thread on this question ...)

Don J
2013-Jun-01, 04:29 AM
The questions remaining for me are:

1) "Could a reaction between the Viking LR soil samples, and any terrestrial contaminants present, and the labelled nutrients added, have resulted in a false positive reading of apparently evolved carbon isotopes?"

No,as demonstrated by the control tests destined to kill living microorganisms by heat but not enough (hot)to destroy the other elements.


2) "Is there something to learn from the SAM GCMS/QMS results, which may be of relevance in the analysis of the Viking LR tests?"

No!
The only lesson learned will be to make better seals to avoid leaks...


The measurement of isotopes is clearly impacted at present in the SAM sample-to-QMS chain, (by its contaminant and its associated by-products). Might this also have happened in Viking's LR isotope counting technology?

The LR instrument was separe from the GCMS ,the only thing it "shared" was the oven used to heat the control samples.
We know also that the scoop was sterilised from Earth organic carbon and Earth living microorganisms due to the high standard of cleaning and sterilisation applied to the Viking probes. Contrary to what happened with Curiosity about the non respect of the sterilisation standard.

Don J
2013-Jun-01, 04:46 AM
Grotzinger and Vasavada have directed their science team to develop a systematic search for organic molecules, driving the rover to locations thought to best sustain carbon. Curiosity is not equipped to find extant life, but there is much to learn about the red planet's ability to preserve organics and how to uncover them.



Hmm .. just sounds like a 'low-ball' to the public, in order to set expectations on the low side as far as finding significant complex organics.

All of which raises the question of the validity of the Viking LR results, the 'asteroids delivering abundant organics' and, if one sticks with this hypothesis, one has no choice other than to elevate the 'destruction' of organics' hypotheses, (as indicated by Vasavada's and Meyer's comments in the article), and of present sub-surface organics hypotheses.

If they really want to find organics they should stop drilling hole in billions years old rocks or taking (dust) sample directly on the Martian surface which is directly exposed to radiations.They should rather start digging 2.5 cm and more below the surface.

But as you know it, there is the other planned mission on the run which will do just that.

Don J
2013-Jun-01, 07:05 AM
I really do not understand why they are sticking so closely to the 'asteroid delivery of complex organics' hypothesis, however(??)

That is not the only expected source of complex organics for Mars at least when Mars was more like Earth ie with water and an atmosphere billions or millions of years ago...
SEARCH FOR EVIDENCE OF PREBIOTIC CHEMISTRY
http://cmex.ihmc.us/exo_strat/Docs/prebiotic.html


This is part of AN EXOBIOLOGICAL STRATEGY FOR MARS EXPLORATION
Prepared by the Exobiology Program Office, NASA HQ
January 1995

-(Cough :STRATEGY which was followed precisely since 1996 and who will last for many,...many decades probably culminating with a sample return and a human mission )-
Details
http://cmex.ihmc.us/exo_strat/exo_strat.html

Selfsim
2013-Jun-01, 09:21 PM
No,as demonstrated by the control tests destined to kill living microorganisms by heat but not enough (hot)to destroy the other elements.Hmm … they heated the control sample to 160 degrees for three hours on VL1 and then only 50, 46 and 51 degrees at three hours on on VL2 with varying degrees of diminished release .. but I'm not sure this shows that there wasn't any contamination effecting the detectors?
(I'm not exactly sure of where I'm going on this one .. the design of this experiment requires intimate knowledge of the equipment design .. which I openly admit to not having .. its complex, y'know ..?)

All I can say (gut feel .. so it doesn't count for much), is that the experiment design assumptions might have been too prescriptive and what was observed doesn't necessarily have to be metabolism that was detected.
(From the experimenter's workbook):

Several assumptions were used in the design and operation of the LR experiment including: 1) life on Mars was carbon based; 2) one or more of the nutrient compounds would be metabolized by any microbial life present; and 3) one end product of metabolism would be a carbon based gas that would rise from the sample for ready detection. Between what Curiosity and Viking has detected so far, and those assumptions, there will be something not yet considered (IMO) .. and that will end up being the discovery from probe explorations on Mars. (IMO .. which, I'll add doesn't count for much … :) )

One obvious thing in common amongst these probes, is the decontamination procedure and the instrument sensitivity.


No!
The only lesson learned will be to make better seals to avoid leaks…It may well be more complicated than that. How come MTBSTFA 'leaks' have found their way into the soil sample chain? There's a couple of things going on here .. eg: (i) the (possible) seal leak and; (ii) the leaking MTBSTFA has somehow found its way into the sample chain … there are design lessons to be learned from both of these aspects (as a very minimum). How about the seals containing the nutrients on Viking LR?


The LR instrument was separe from the GCMS ,the only thing it "shared" was the oven used to heat the control samples.Yes .. but I wasn't referring to any GCMS results/components. I'm only querying the LR isotope detector. Do you know what type it is, how it works, how it was cleaned, how it was calibrated in situ? .. Why should its results be exempt from scrutiny? Maybe I've just missed why .. this is a pretty complex testing process .. and it has been very carefully thought out and pre-tested on Earth, (I'm not at all critical of that aspect) .. but the 'unexpected' still remains as a 'possible' cause of the LR results. (I'm startin' to go all 'astrobiological' here !! (Shock!, Horror! :p :) ) )


We know also that the scoop was sterilised from Earth organic carbon and Earth living microorganisms due to the high standard of cleaning and sterilisation applied to the Viking probes.And this cleaning and sterilisation process might also be a contributing factor towards the apparent metabolism detected by the LR instrument. Has anybody thought about that?

Contrary to what happened with Curiosity about the non respect of the sterilisation standard.You mean the drill bit incident prior to launch(?)
Perhaps the pre-launch cleaning process, combined with the assumption that cumulative subsequent martian samples erases that contamination, might be an issue!?! … Just ride with me here for a bit .. I realise you're convinced that the LR results were 'problem-free' .. but were they? The Rocknest drift scoop was about the same depth as the Viking scoops .. so it can be said that the concentration of organics, (if present), is low at Rocknest*. How could a Rocknest sample possibly generate the apparent metabolism of Viking LR, if a hypothetical LR experiment was applied to that scoop? (Remember the SAM GCMS/QMS/TLS are way more sensitive to organics, than Viking's GCMS was. Having said that, the contaminant concentration seems to be sufficient to produce measurable organics at fairly low concentrations .. sufficient to mask any extant organics (if present). I wonder if an LR experiment at Rocknest might have been able to detect 'metabolism' at those low levels, however?)

Footnote:
* Compared with the concentrations such as the Antarctican sample discussed earlier in this thread.

Selfsim
2013-Jun-01, 09:29 PM
If they really want to find organics they should stop drilling hole in billions years old rocks or taking (dust) sample directly on the Martian surface which is directly exposed to radiations.They should rather start digging 2.5 cm and more below the surface.The Rocknest drift was easily that deep (I believe) even though it was a drift sample .. not exactly the same as extant soil … however, I'm inclined to agree with what you say.
The reason given for a second drill sample was: "to confirm the Klein results" .. which is very poorly worded (IMO). I think what they're really attempting to do is to 'calibrate' the results using commonality of readings within the same geology type .. so as to enable them to minimise (or even eliminate) the terrestrial (or even MTBSTFA) contaminant aspects?


But as you know it, there is the other planned mission on the run which will do just that.But they need evidence in support of that mission .. so they'll have to dig with the scoop again.
Patience is needed here, methinks ..

Selfsim
2013-Jun-01, 09:48 PM
That is not the only expected source of complex organics for Mars at least when Mars was more like Earth ie with water and an atmosphere billions or millions of years ago...
SEARCH FOR EVIDENCE OF PREBIOTIC CHEMISTRY
http://cmex.ihmc.us/exo_strat/Docs/prebiotic.html
Yep .. dig! (There's no reason not to test that hypothesis while they can).
.. Except, that is, when you've got a bunch of 'speculationist Astrobiologists', who have so many unconstrained speculations, (and their own pet ones), steering' a hunt for a holy grail!


This is part of AN EXOBIOLOGICAL STRATEGY FOR MARS EXPLORATION
Prepared by the Exobiology Program Office, NASA HQ
January 1995

-(Cough :STRATEGY which was followed precisely since 1996 and who will last for many,...many decades probably culminating with a sample return and a human mission )-
Details
http://cmex.ihmc.us/exo_strat/exo_strat.htmlLotsa reading to do there …

I shut-down when I read this nonsense word-soup gobbledygook …
It is possible that all martian chemistry is prebiotic, in the sense that it took place without the agency of a pre-existing biota. Whether it is prebiotic in the sense of having led to a martian biota is less clear.If it turns out that there's no evidence of life, past or present, (LR results excepted … until replicated), then the chemistry on Mars cannot be said to be 'pre-biotic'. At present, the term 'pre-biotic chemistry' only has scant meaning on Earth .. and certainly has no meaning in the case of Mars!

The search for exo-life is the test for our present universal hypothesis of life. Imposing the term 'pre-biotic chemistry' where life has not yet been detected, is putting the cart way before the horse!

… Yet more confusion and unclarity being thrown into the melting pot by Astrobiological gobbledyspeak!

Don J
2013-Jun-02, 02:03 AM
… Yet more confusion and unclarity being thrown into the melting pot by Astrobiological gobbledyspeak!
Confusion,ambiguity that is all that is needed for a Mars mission.
It all here:
http://cmex.ihmc.us/exo_strat/exo_strat.html


Lotsa reading to do there …

I shut-down when I read this nonsense word-soup gobbledygook …

I have not reading all that stuff...
So you put some doubt about that STRATEGY of Mars exploration prepared by the Exobiology Program Office, NASA HQ in
January 1995 ?...
It maybe ironic to realise that the only new discovery about Mars environment since the Mariner probe and Viking probes was the discovery of perchlorate made by Pheonix in 2006.

Selfsim
2013-Jun-02, 03:09 AM
Confusion,ambiguity that is all that is needed for a Mars mission.
It all here:
http://cmex.ihmc.us/exo_strat/exo_strat.html

I have not reading all that stuff...
So you put some doubt about that STRATEGY of Mars exploration prepared by the Exobiology Program Office, NASA HQ in
January 1995 ?...Don't get me started, eh? (Although, I'll refrain from joining in your assertion of the deliberateness of the 'confusion/ambiguity').

Mars organics, if it exists en masse, won't be effected by some 'pleasingly popular' strategy.


It maybe ironic to realise that the only new discovery about Mars environment since the Mariner probe and Viking probes was the discovery of perchlorate made by Pheonix in 2006.I think that's being a little harsh. The orbiters and rovers have quantified lots of previously unknown things, and accumulated lots of mudane environmental data, which is ultimately necessary to eliminate the uncertainties, for when and if something does actually get discovered.

Mind you, the fundamental cause of these orbiter and rover measurements, was simply exploration. (Ie: going to 'check out' what's there) ... not some directed search for something which may or may not exist ... (ie: 'Exo' .. or 'Astro'-'biology'). There are Viking experimental results which still can't be explained (by anybody) as the result of that approach (eg: GEX PR) ... and that's regardless of any 'next mission' agendas.

Don J
2013-Jun-02, 06:32 PM
The Rocknest drift scoop was about the same depth as the Viking scoops .. so it can be said that the concentration of organics, (if present), is low at Rocknest*.


Do you have a reference about how deep it was?


I wonder if an LR experiment at Rocknest might have been able to detect 'metabolism' at those low levels, however?)

If they really want to check every hypothesis why not include a LR instrument ?The LR on Viking was about 25 pounds with the actual technology it must be possible to make one even smaller. So the size issue is not the problem.

Don J
2013-Jun-02, 06:44 PM
There are Viking experimental results which still can't be explained (by anybody) as the result of that approach (eg: GEX PR) ... and that's regardless of any 'next mission' agendas.
You mean the positive response obtained even with the sterilised control samples from the GEX and PR ...there is effectively a little mystery there.That is why you think that chemical or biological contaminant from Earth may be in cause?That hypothesis was surely studied by someone somewhere.
Scroll down to
The Viking Biology Experiment
http://www.msss.com/http/ps/life/life.html

Wathever the cause it did not affected the LR instrument who reported negative results on all sterilised control samples destined to kill living microorganisms.

Selfsim
2013-Jun-02, 09:18 PM
You mean the positive response obtained even with the sterilised control samples from the GEX and PR ...there is effectively a little mystery there.That is why you think that chemical or biological contaminant from Earth may be in cause?That hypothesis was surely studied by someone somewhere.
Scroll down to
The Viking Biology Experiment
http://www.msss.com/http/ps/life/life.html Interestingly, from the 1995(?) 'Exobiology Strategy Report':

The Pyrolytic Release Experiment
This experiment, which was performed 9 times, had as its underlying basis the assumption that some photosynthetic species, capable of assimilating either CO2 or CO, might be present in the martian surface.
...
Extremely small, but statistically significant, amounts of incorporation of the initial gas mixture (presumably into organic compounds) were seen in these experiments. However, the results have been interpreted as being nonbiological on the following grounds: heating one sample to "sterilizing" temperature (90oC) for 2 hr did not reduce the level of incorporation; addition of water vapor (to supply reducing power for the reaction) totally abolished the reaction; and the reaction proceeded in the dark. To date, no satisfactory explanation has been given to account for these results.According to the Malin Space Systems report, the results for the PR experiment were:

Sample: carbon detected
Control: carbon detected

whereas if life was present, the following result was expected:
Sample: carbon detected
Control: none detected

If life wasn't present:
Sample: none detected
Control: none detected


Wathever the cause it did not affected the LR instrument who reported negative results on all sterilised control samples destined to kill living microorganisms... and impaired 'apparent metabolism' for lowered temperatures.

All this makes one wonder what could each experiment have in common (equipment, cleaning procedures, common contaminants, etc) that may have caused such unexpected results? Was the C14 detector technology really detecting emissions only coming from the samples? I notice calibration procedures included establishing the background radiation levels. I wonder whether these emissions change during these experiments? How would they know if it did?
(I notice that the calibration of the detectors also includes counting the RPG emissions from the spacecraft power supplies … does this suggest screening issues?)

Having suggested this, the detectors do seem to have been tuned to discriminate on C14 isotope emissions (AIUI).

Don J
2013-Jun-03, 01:36 AM
Wathever the cause it did not affected the LR instrument who reported negative results on all sterilised control samples destined to kill living microorganisms.

. and impaired 'apparent metabolism' for lowered temperatures.

You may find interesting to discover the other sterilisation method used.Note that each Martian soil sample providing a LR positive result ie(metabolism) was followed by a sterilised control sample of Martian soil taken from the same location.

http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htm

Don J
2013-Jun-04, 07:38 PM
Interestingly, from the 1995(?) 'Exobiology Strategy Report':
According to the Malin Space Systems report, the results for the PR experiment were:

Sample: carbon detected
Control: carbon detected

whereas if life was present, the following result was expected:
Sample: carbon detected
Control: none detected

If life wasn't present:
Sample: none detected
Control: none detected

If you read further they said that:
"Only the LR experiment appears to have met the criteria for life detection,"
http://www.msss.com/http/ps/life/life.html
If life was present, the following result was expected for the LR instrument:
Sample :labeled gas emitted
Control :none

The results for the LR instrument were:

Sample :labeled gas emitted
Control :none

Paul Wally
2013-Jun-05, 01:29 PM
The figures were derived from a kinematic model based on the terrestrial GCMS and LR data sampling. It interesting that now you see such information as 'their interpretation' ie: not physical reality.
It seems you are now arguing my persistent point about the non-(physical) reality of theoretical models). Good to see!

As I tried to get across, theories are there to represent a picture of reality, but that picture is falsifiable by data. There's no way of empirically knowing that we have a correct view of reality. It's seems however that the very data that's suppose to test our theories is ambiguous in the case of Viking. If people cannot agree on what was measured then that's that. No amount of discussion is going to settle the issue, because it is the data that's suppose to settle the issue.



Actually details of the John Klein results have eluded all my searches!
(I'm starting to dream up conspiracies of deliberate suppression of the SAM results at the Klein drilling site! (… Oh no ..!.. :) ))
The contamination issue existed at the Rocknest drift scoop, which occurred before the Klein drill. It would have been interesting to see whether the MTBSTFA levels at Klein had changed (or not). I'm eager to see any SAM results for Cumberland .. (I hope they are more easily findable than the Klein details).

March 12 Curiosity News conference (http://www.youtube.com/watch?v=fvCfOVGHWCc) presents some results. You can skip to about 19min for the chlorohydrocarbons that were detected above background levels.

Selfsim
2013-Jun-05, 10:10 PM
If you read further they said that:
"Only the LR experiment appears to have met the criteria for life detection,"
http://www.msss.com/http/ps/life/life.html
If life was present, the following result was expected for the LR instrument:
Sample :labeled gas emitted
Control :none

The results for the LR instrument were:

Sample :labeled gas emitted
Control :noneWell, as we started out, the LR experiment, in isolation, may have met the criterion for its own version of 'life' detection, (false positives aside). However, in order for the LR experiment results to be declared as having detected 'life', the assumptions leading to the experiment also needed to be grounded in evidence from the surroundings. Those results included the results from the GCMS instrument, whose sensitivity appears to have been incapable of returning confirmative readings regarding the necessary chemical nature of any (low concentration) organics present. The confirmation wasn't forthcoming.

Just for the record, the assumptions for each experiment, stated rather concisely in the Strategy document, were:

i) PR: That some photosynthetic species, capable of assimilating either CO2 or CO, might be present in the martian surface;

ii) LR: That organisms might be present in the surface of Mars that were capable of metabolizing simple carbon compounds similar to those readily formed in laboratory simulations of early organic chemical evolution. (Notice that the presence of 'organics' is key to the validity of these assumptions);

iii) GEX (wet): That surface samples contained heterotrophic micro-organisms requiring organic substrates and possibly various organic growth factors for their metabolism, and that metabolism would involve the uptake or release of metabolic gases;

iv) GEX (humid): That indigenous organisms only required the presence of moisture in order to elicit their metabolism.

These tests, taken as a collective whole, required confirmation of complex organics to be present in the samples taken, and it was necessary to confirm this as a baseline for subsequent results interpretation. When taken individually (like LR), the results can only confirm consistency with the assumptions .. but these same results cannot eliminate uncertainties in those same assumptions, or of other explanations/assumptions.

This, (IMO), is exactly why the tenets of Astrobiology should never form the sole basis of exploration of environments beyond Earth. Astrobiological tenets lack the necessary constraints, and produces nothing more than more 'possibilities'. In the case of Viking results interpretation, these 'other possibilities' actually worked against convergence towards a life conclusion, thus allowing for the growth of conspiracy theories (such as your personal one) ...

Exactly how does that support science?

Selfsim
2013-Jun-05, 10:22 PM
As I tried to get across, theories are there to represent a picture of reality, but that picture is falsifiable by data. There's no way of empirically knowing that we have a correct view of reality. Perhaps there is no reality …
It's seems however that the very data that's suppose to test our theories is ambiguous in the case of Viking. If people cannot agree on what was measured then that's that. No amount of discussion is going to settle the issue, because it is the data that's suppose to settle the issue. Yep .. I agree.


March 12 Curiosity News conference (http://www.youtube.com/watch?v=fvCfOVGHWCc) presents some results. You can skip to about 19min for the chlorohydrocarbons that were detected above background levels.Thanks for that .. I was watching this YouTube, just recently. Mahaffy sort of skimmed over the contaminant issue. The graphs they produced lack detail, and the interpretive analysis is also still conspicuously absent (months after the event!)

… (Still no preliminary results from Cumberland, either .. even in the recent June 5 Curiosity status update announcement).

He did point out (from the scoop photo) that the scoop still contained some remnant material from Rocknest, interestingly. One has to wonder how they eliminate that past sample matter from current analysis? Seems like a pretty imprecise diagnosis method to me(?)

Don J
2013-Jun-06, 06:15 PM
Well, as we started out, the LR experiment, in isolation, may have met the criterion for its own version of 'life' detection, (false positives aside).

Which false positives are you talking about ?
Looking at the official Viking LR datas there is positive life detection by the LR instrument.
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htm


However, in order for the LR experiment results to be declared as having detected 'life', the assumptions leading to the experiment also needed to be grounded in evidence from the surroundings. Those results included the results from the GCMS instrument, whose sensitivity appears to have been incapable of returning confirmative readings regarding the necessary chemical nature of any (low concentration) organics present. The confirmation wasn't forthcoming.

The confirmation of the detection of organic carbon was not established then.But it is now established by the the Journal Of Geophysical Research. Navarro-Gonzalez reanalysis of Viking GCMS datas.
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf


Reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.

Don J
2013-Jun-06, 06:27 PM
It's seems however that the very data that's suppose to test our theories is ambiguous in the case of Viking. If people cannot agree on what was measured then that's that. No amount of discussion is going to settle the issue, because it is the data that's suppose to settle the issue.

New datas are now available.(see post #242)
The reanalyse of the Viking CGMS datas by the Journal Of Geophysical Research settle the issue about the detection of organic carbon at Viking landing site 1 and 2.

Selfsim
2013-Jun-06, 09:25 PM
Which false positives are you talking about ?The possibility of a false positive LR result was not eliminated. The detection of specifically, complex carbon based organics at the sample site(s), and its subsequent classification, may have sufficed.


Looking at the official Viking LR datas there is positive life detection by the LR instrument.
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/index.htmThere was a positive detection of apparent metabolism. This is not necessarily a positive detection of life, (although the experiment assumptions presume this to be so). More data from different tests is needed.


The confirmation of the detection of organic carbon was not established then.But it is now established by the the Journal Of Geophysical Research. Navarro-Gonzalez reanalysis of Viking GCMS datas.
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf

A chemical kinetics model was developed to predict the degree of oxidation and chlorination of organics in the Viking oven. Reinterpretation of the Viking results therefore suggests ≤0.1% perchlorate and 1.5–6.5 ppm organic carbon at landing site 1 and ≤0.1% perchlorate and 0.7–2.6 ppm organic carbon at landing site 2. The detection of organics on Mars is important to assess locations for future experiments to detect life itself... and no detection of organics was made .. so the location of the hypothesised life (including VL1's and VL2's sample sites) cannot be predicted or 'post-dicted', in the light of reinterpretation of past results, using a model which makes further assumptions.

Models do not replace empirical test results (or the absence of them). This is the role and purpose of experiment in the scientific process.

Don J
2013-Jun-07, 03:17 AM
.. and no detection of organics was made .. so the location of the hypothesised life (including VL1's and VL2's sample sites) cannot be predicted or 'post-dicted', in the light of reinterpretation of past results, using a model which makes further assumptions.

Models do not replace empirical test results (or the absence of them). This is the role and purpose of experiment in the scientific process.
Ahem!from post 222


Oh, and just for comparison, the Chilean Atacama desert sample used in the 2010 Viking re-evaluation study (Navaro-Gonzales etal) contained 32 +/- 6ppm organic carbon ... and that sample included terrestrial bio-organics.
How do you explain that the GCMS used to do the tests have not detected the presence of any organic carbon in the Atacama desert sample who contained 32 +/- 6ppm organic carbon + terrestrial bio-organics ?
1-Does that mean that organics were not present in the sample?
2-Or, as you know it ,the cause is the presence of perchlorate in the sample who when heated at 200+degree celsius destroy the presence of organic carbon?

If you look carefully at the study you will notice that the Earth sample of (Mars like soil) from the Chilian Atacama desert containing 32 +/- 6ppm organic carbon also produce the chloromethane and dichloromethane(by-product) when mixed with 1 wt% magnesium perclhorate and heated at 500 degree celcius using the same Viking detection protocols. That is from these results that a chemical kinetics model was developped to predict the level of oxidation and chlorination of organics in the Viking oven.From that chemical kinetics model they were able to determine the level of perchlorate and organic carbon in the Martian soil samples from the reevaluation of the Viking GCMS results.
http://www.earth.northwestern.edu/people/seth/351/mckay.viking.pdf
-For those just joining the discussion-we have a discussion about it in page 4 -
For details:
http://cosmoquest.org/forum/showthread.php?143405-Mars-Soil-Resembles-Veggie-Garden-Dirt-Lander-Finds/page4

Selfsim
2013-Jun-07, 04:32 AM
Ahem!from post 222

How do you explain that the GCMS used to do the tests have not detected the presence of any organic carbon in the Atacama desert sample who contained 32 +/- 6ppm organic carbon + terrestrial bio-organics ?
1-Does that mean that organics were not present in the sample?Not according to this ..
Yungay {Atacama} contains Mars-like soils in the surface that have no culturable bacteria (<102 colony-forming units per gram), low levels of extractable DNA, and low organic concentrations (20–40 ppm C) that become detectable at temperature regimes greater than investigated by the Viking mission, and the presence of a non-chirally specific oxidant that consumes organics in aqueous solution.

2-Or, as you know it ,the cause is the presence of perchlorate in the sample who when heated at 200+degree celsius destroy the presence of organic carbon?I can confirm that's what these guys are saying ..
However, if Yungay soils are spiked with magnesium perchlorate and treated using the Viking protocol, the low level organics are combusted in the oven but surprisingly a trace amount is quenched in the form of chlorohydrocarbons, namely chloro and dichloromethane

The terrestrial/Atacama test is still a terrestrial analog/model. The martian environment is different, as I'm sure you'd agree … (As are the actual instruments doing the respective tests, in the respective locations (ie: Earth, Mars) ).

Unforeseen or unknown contaminant(s) of either terrestrial or martian origin, capable of producing similar results have not been ruled out by the terrestrial analog/model.


If you look carefully at the study you will notice that the Earth sample of (Mars like soil) from the Chilian Atacama desert containing 32 +/- 6ppm organic carbon also produce the chloromethane and dichloromethane(by-product) when mixed with 1 wt% magnesium perclhorate and heated at 500 degree celcius using the same Viking detection protocols. That is from these results that a chemical kinetics model was developped to predict the level of oxidation and chlorination of organics in the Viking oven.A terrestrial oven .. not the martian based Viking oven/detection system/soil sample.
From that chemical kinetics model they were able to determine the level of perchlorate and organic carbon in the Martian soil samples from the reevaluation of the Viking GCMS results.They were able to approximate the equivalent amount of organics that would reproduce the measured levels of (di)chloromethane(s) detected on the martian apparatus, the origins of which, remain unknown and unconstrained by the terrestrial analogy/model.

It may seem like a fine line (and I'd agree), but all we have to go on, is the optimistic Navaro-Gonzales (etal) analysis/report, (which includes the optimistic views of one Chris McKay) and Levin, himself .. (Oh yes .. and a pending MSL/SAM Klein/Cumberland analysis, known to include organic contaminants, which may be able to be distinguished from the soil/rock drill samples, with further analysis .. :) )

Don J
2013-Jun-07, 04:53 AM
The terrestrial/Atacama test is still a terrestrial analog/model. The martian environment is different, as I'm sure you'd agree … (As are the actual instruments doing the respective tests, in the respective locations (ie: Earth, Mars) ).


An analysis of how the perchlorate is formed in the Atacama desert made its way to explain how it is also produced on Mars.
http://onlinelibrary.wiley.com/doi/10.1029/2009JE003425/abstract
Atmospheric origins of perchlorate on Mars and in the Atacama


[1] Isotopic studies indicate that natural perchlorate is produced on Earth in arid environments by the oxidation of chlorine species through pathways involving ozone or its photochemical products. With this analogy, we propose that the arid environment on Mars may have given rise to perchlorate through the action of atmospheric oxidants. A variety of hypothetical pathways can be proposed including photochemical reactions, electrostatic discharge, and gas-solid reactions. Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we made a preliminary study of the means to produce Atacama perchlorate to help shed light on the origin of Martian perchlorate. We investigated gas phase pathways using a 1-D photochemical model. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. The feasibility of gas phase production for the Atacama provides justification for future investigations of gas phase photochemistry as a possible source for Martian perchlorate.

Selfsim
2013-Jun-07, 05:48 AM
An analysis of how the perchlorate is formed in the Atacama desert made its way to explain how it is also produced on Mars.… "to explain how it might be produced on Mars" ...

The feasibility of gas phase production for the Atacama provides justification for future investigations of gas phase photochemistry as a possible source for Martian perchlorate. … one testable hypothesis …

Selfsim
2013-Jun-07, 05:59 AM
<The emboldened section below was added following my last response>

Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site … one of many physical reasons to pursue the hypothesis. (I'm sure they'll find many others .. not the least of which may well be variations in perchlorate concentrations across a geographically dispersed area).

I wonder how the Phoenix perchlorate concentration compares with SAM/MSL's?
(Phoenix was in the northern polar region .. MSL is in the equatorial region …)

Selfsim
2013-Jun-07, 06:52 AM
The point I'm making here, (as with so many other LiS discussions), is that the chemistry and physics of lab-controlled, or even natural terrestrial environment 'controlled' conditions (Atacama, Antarctica, etc), is not in question ... the assumptions that those same conditions might be replicated over time, and in precise detail, in a natural martian environment, are.

When looking back over geological scale timeframes, the variables involved resulting in Atacama soil chemistry would have to be enormous.
So often we assume the differences between our own environments and other exo-environments, to be not worthy of consideration (mostly out of pure convenience), but such assumptions are without basis, particularly when we have so little direct evidence of precise similarity, as in the case of Mars'. This is the purpose of sending a rover with non-specifically, generally equipped experimentation apparatus, is it not? Replacing the experiment with a model/theory/hypothesis based on terrestrial conditions, defeats the whole purpose of gathering data in situ on Mars.

Viking unfortunately, didn't gather the necessary full set of baseline data there, in order for its LR results to carry their anticipated full meaning. Over time and gradual build-up of data on Mars, we might retrieve that situation ... in the meantime, terrestrial and lab (controlled) conditions, serve only as gross approximations, to guide further research on Mars ... not as a 'truth mechanism' for telling us what went on there in the past (or even in the present) ...