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A.DIM
2013-Dec-02, 04:17 PM
or in other words: How Life-Bearing Rocks from the Chicxulub Asteroid Impact must have spread through the Solar System (https://medium.com/the-physics-arxiv-blog/56e227224a25).

Often we consider panspermia hypotheses wherein life arrives on Earth from elsewhere. This OOL(on Earth) scenario is not well liked because it moves the problem of abiogenesis off planet. The search for life elsewhere in our system (eg. Mars) carries with it then, the potential discovery of a so called "holy grail:" a separate genesis event and alien lineage. The discovery of such a "holy grail", in my mind, is highly unlikely when we consider material exchange in our system, especially material originating from Earth.

Seeding Life ... (http://arxiv.org/abs/1311.2558)
Material from the surface of a planet can be ejected into space by a large impact, and could carry primitive life forms with it. We performed n-body simulations of such ejecta to determine where in the Solar System rock from Earth and Mars may end up. We find that, in addition to frequent transfer of material among the terrestrial planets, transfer of material from Earth and Mars to the moons of Jupiter and Saturn is also possible, but rare. We expect that such transfer is most likely during the Late Heavy Bombardment or during the next one or two billion years. At this time, the icy moons were warmer and likely had little or no icy shell to prevent meteorites from reaching their liquid interiors. We also note significant rates of re-impact in the first million years after ejection. This could re-seed life on a planet after partial or complete sterilization by a large impact, which would aid the survival of early life during the Late Heavy Bombardment.

What with all the material exchange in our system how can anyone think there's much possibility of discovering a separate genesis? Were you to ask me, I'd predict any and all life found in our solar system will be related with no hope of discovering where it originated (maybe even how).

Selfsim
2013-Dec-03, 06:55 AM
or in other words: How Life-Bearing Rocks from the Chicxulub Asteroid Impact must have spread through the Solar System (https://medium.com/the-physics-arxiv-blog/56e227224a25).

Often we consider panspermia hypotheses wherein life arrives on Earth from elsewhere. This OOL(on Earth) scenario is not well liked because it moves the problem of abiogenesis off planet. The search for life elsewhere in our system (eg. Mars) carries with it then, the potential discovery of a so called "holy grail:" a separate genesis event and alien lineage. The discovery of such a "holy grail", in my mind, is highly unlikely when we consider material exchange in our system, especially material originating from Earth. So do opinions of 'likelihood' or 'unlikelihood' really matter at all, when the exploration of local planets is already underway, and said exploration is ultimately the only way to find out?


Seeding Life ... (http://arxiv.org/abs/1311.2558)

Material from the surface of a planet can be ejected into space by a large impact, and could carry primitive life forms with it. We performed n-body simulations of such ejecta to determine where in the Solar System rock from Earth and Mars may end up. We find that, in addition to frequent transfer of material among the terrestrial planets, transfer of material from Earth and Mars to the moons of Jupiter and Saturn is also possible, but rare. We expect that such transfer is most likely during the Late Heavy Bombardment or during the next one or two billion years. At this time, the icy moons were warmer and likely had little or no icy shell to prevent meteorites from reaching their liquid interiors. We also note significant rates of re-impact in the first million years after ejection. This could re-seed life on a planet after partial or complete sterilization by a large impact, which would aid the survival of early life during the Late Heavy Bombardment.

What with all the material exchange in our system how can anyone think there's much possibility of discovering a separate genesis? Were you to ask me, I'd predict any and all life found in our solar system will be related with no hope of discovering where it originated (maybe even how).Well thank you kindly for that 'prediction'. :)

Given that there is insufficient data, on the other hand, to make any scientific predictions I guess there's not much further to discuss then, eh? .. :)

Cheers

Noclevername
2013-Dec-03, 07:54 AM
I predict... That despite having "not much further to discuss" this thread will go on for pages, covering old familiar ground. :D

Solfe
2013-Dec-03, 01:16 PM
I would be interested in "life can spread via impact events" topic, but word "must" in that title is a little overpowering.

We have had landers and rovers on a just a handful of bodies, I would think that finding an amino acids or proteins would require a little more effort on our part.

A.DIM
2013-Dec-03, 05:17 PM
So do opinions of 'likelihood' or 'unlikelihood' really matter at all, when the exploration of local planets is already underway, and said exploration is ultimately the only way to find out?

Well thank you kindly for that 'prediction'. :)

Given that there is insufficient data, on the other hand, to make any scientific predictions I guess there's not much further to discuss then, eh? .. :)

Cheers

You’re welcome kindly, Selfsim, although I didn’t offer it as a “scientific” prediction (even while it is based on observation, experiment, facts ;) ). You’re welcome too, to discuss no further those topics with speculative elements or insufficient data; I’ve read how this worries you so.

It would seem though, those who guide our space programs hold opinions that there’s some likelihood of discovering “alien” life and or a second genesis in our solar system, as if its many bodies are closed systems, cutoff from the rest, each in its own bubble. Is this reasonable? Given what we know, and are learning, about habitability, extremophiles, material exchange … any search for the “holy grail” in our solar system strikes me as misguided.

What are the best reasons to think a separate genesis event took place in our system, that an independent lineage could exist on Mars or the moons of Jupiter? How might this mode of thought inform their approach to space exploration?

Aside: Are they really even looking?

Cheers!

PetersCreek
2013-Dec-03, 08:25 PM
Warning/advice to all: do not contribute to this thread becoming the kind of festering, virulent snarkfest (or worse) that so many LiS have devolved to. The thread won't be pretty and neither will the moderation.

Noclevername
2013-Dec-04, 08:01 AM
How might this mode of thought inform their approach to space exploration?

Aside: Are they really even looking?


The answer to both questions is the same; it should not and does not inform their decisions. They are looking for life, period. Determining its origin(s) will be done if and after some life is found.

R.A.F.
2013-Dec-04, 03:03 PM
...but word "must" in that title is a little overpowering.

Immediately followed by...

Earth rocks capable of carrying and protecting life have probably to travelled to Europa, Titan and beyond, say astrobiologists.


"Must" and "probably" are not words I would use to describe something that at this time is completely speculative.

A.DIM
2013-Dec-04, 03:17 PM
I would be interested in "life can spread via impact events" topic, but word "must" in that title is a little overpowering.

We have had landers and rovers on a just a handful of bodies, I would think that finding an amino acids or proteins would require a little more effort on our part.

Indeed, a little more effort (I daresay any at all!) could be as simple as sending actual life detection packages. Not since Viking has this been done.

And I too was struck by the "must have..." in the article's title, although the paper is rather more specific. I wonder how trustworthy their modelling is?

Noclevername
2013-Dec-04, 03:25 PM
Indeed, a little more effort (I daresay any at all!) could be as simple as sending actual life detection packages. Not since Viking has this been done.


I would think accurate ET life detection would be more complex than that. For example, how to avoid contaminating the probes with terrestrial microbes, or how to tell an abiotic chemical reaction from actual life?

A.DIM
2013-Dec-04, 03:27 PM
The answer to both questions is the same; it should not and does not inform their decisions. They are looking for life, period. Determining its origin(s) will be done if and after some life is found.

Well, I don't think they're really looking for life but the idea of separate genesis / independent lineage does indeed inform their decisions; has since the 60s what with "planetary protection" and all. Then, it was "back contamination" where viruses or microbes were returned to Earth on spacecraft; now, it is forward contamination where life from Earth is transferred elsewhere. Why do you suppose such great measures are taken with sterilization in "clean rooms" for spacecraft? Because there's hope that should life be found elsewhere, we might identify it as a separate lineage, the holy grail.

A.DIM
2013-Dec-04, 03:32 PM
I would think accurate ET life detection would be more complex than that. For example, how to avoid contaminating the probes with terrestrial microbes, or how to tell an abiotic chemical reaction from actual life?

As I understand it, Levin's Labeled Release experiment modified to detect chirality would do the trick.

Noclevername
2013-Dec-04, 03:34 PM
Well, I don't think they're really looking for life but the idea of separate genesis / independent lineage does indeed inform their decisions; has since the 60s what with "planetary protection" and all. Then, it was "back contamination" where viruses or microbes were returned to Earth on spacecraft; now, it is forward contamination where life from Earth is transferred elsewhere. Why do you suppose such great measures are taken with sterilization in "clean rooms" for spacecraft? Because there's hope that should life be found elsewhere, we might identify it as a separate lineage, the holy grail.

Er, no. Clean rooms are used because the precision instruments on the probes require dirt-free environments to be built accurately. The probes themselves are not medically sterile.

A.DIM
2013-Dec-04, 04:07 PM
Er, no. Clean rooms are used because the precision instruments on the probes require dirt-free environments to be built accurately. The probes themselves are not medically sterile.

In part, perhaps, but not really ...

Recently, there was The Overprotection of Mars? (http://www.astrobio.net/exclusive/5817/the-overprotection-of-mars) which highlights some of the issues surrounding the the idea of "contamination."

COSPAR Planetary Protection guidelines are, in large part, to guard against biological contamination, not mere dirt and dust.

Noclevername
2013-Dec-04, 05:13 PM
In part, perhaps, but not really ...

Recently, there was The Overprotection of Mars? (http://www.astrobio.net/exclusive/5817/the-overprotection-of-mars) which highlights some of the issues surrounding the the idea of "contamination."

COSPAR Planetary Protection guidelines are, in large part, to guard against biological contamination, not mere dirt and dust.

You are correct. I wasn't aware of the specifics about those guidelines.

However, the factors noted in the article you linked hold true whether the prospective life we search for is native or a long-lost cousin-- either way, bringing along our own present-day germs could yield a false positive for ETL. So what procedural differences would you introduce?

Selfsim
2013-Dec-04, 09:29 PM
As I understand it, Levin's Labeled Release experiment modified to detect chirality would do the trick.Well Levin's LR tests didn't 'do the trick' once before … so why would you say it would in the future?

Also, Viking executed extensive probe decontamination procedures and control tests of the test gear in transit .. and it still didn't yield an unambiguous result.

The motivating issue at fault is not about whether anyone's looking for a separate abiogenesis or not … its sending expensive and bulky test equipment under the ideologically based assumption that the target its designed to detect, is present in the first place (with absolutely zip prior evidence for thinking that it is). If the equipment was micro-miniaturised, fuel efficient and doesn't compromise more important data retrieval in any significant way ,there may be a slim chance of getting it sent on a remote probe to a distant planet.

Test gear for initial probes should be generically designed, first and foremost .. ie: capable of guaranteeing that useful data will be returned about simpler phenomena. In order to conclude 'life exists' (via remote data gathering) a lot of other environmental variables have to be eliminated first. This is what Viking didn't do. Life has to be visible at some macro-scale observational levels before any biochemical analysis has its necessary context for conclusion formation.

Worrying about whether the target 'might' represent a second abiogenesis event or not is putting the cart wayyyy before the horse, given present-day biology technological status!

A.DIM
2013-Dec-05, 03:09 PM
You are correct. I wasn't aware of the specifics about those guidelines.

However, the factors noted in the article you linked hold true whether the prospective life we search for is native or a long-lost cousin-- either way, bringing along our own present-day germs could yield a false positive for ETL. So what procedural differences would you introduce?

If Earthly germs can survive the trip on spacecraft to provide false positives once there, what makes you think they couldn't have been transported via natural mechanisms previously?
Sterilization against "contamination" then, is misguided and wasteful, with time and money.
I do away with most of the "clean room" procedures.

A.DIM
2013-Dec-05, 03:35 PM
Well Levin's LR tests didn't 'do the trick' once before … so why would you say it would in the future?

Also, Viking executed extensive probe decontamination procedures and control tests of the test gear in transit .. and it still didn't yield an unambiguous result.

Sure it did, it met premission criteria for positive detection, at both locations. Only if exotic chemistry is invoked do the findings become "ambiguous."


The motivating issue at fault is not about whether anyone's looking for a separate abiogenesis or not … its sending expensive and bulky test equipment under the ideologically based assumption that the target its designed to detect, is present in the first place (with absolutely zip prior evidence for thinking that it is). If the equipment was micro-miniaturised, fuel efficient and doesn't compromise more important data retrieval in any significant way ,there may be a slim chance of getting it sent on a remote probe to a distant planet.

Test gear for initial probes should be generically designed, first and foremost .. ie: capable of guaranteeing that useful data will be returned about simpler phenomena. In order to conclude 'life exists' (via remote data gathering) a lot of other environmental variables have to be eliminated first. This is what Viking didn't do. Life has to be visible at some macro-scale observational levels before any biochemical analysis has its necessary context for conclusion formation.

Worrying about whether the target 'might' represent a second abiogenesis event or not is putting the cart wayyyy before the horse, given present-day biology technological status!

Whatever "biology technological status" is, the fact remains that the motivating issue is the assumption that life exists elsewhere, with the paramount question being, "is it independent of Earth life?"

Here's an interesting proposal to detect ET life in situ: MICROBIAL FUEL CELLS APPLIED TO THE METABOLICALLY -
BASED DETECTION OF EXTRATERRESTRIAL LIFE (http://arxiv.org/ftp/arxiv/papers/1006/1006.1585.pdf).

Noclevername
2013-Dec-05, 06:56 PM
If Earthly germs can survive the trip on spacecraft to provide false positives once there, what makes you think they couldn't have been transported via natural mechanisms previously?

For one, a several million year shorter transport time. For another, softer landings... and launches. A brief exposure to vacuum and radiation is not the same as Riding The Wild Meteoroid for eons, with an Earth Shattering Kaboom at either end.


Sterilization against "contamination" then, is misguided and wasteful, with time and money.
I do away with most of the "clean room" procedures.

Er, then how do you tell which microbes you're detecting?

Selfsim
2013-Dec-05, 09:30 PM
Sure it did, it met premission criteria for positive detection, at both locations. Only if exotic chemistry is invoked do the findings become "ambiguous."No .. the results were contradictory when viewed from the hypothesis which drove the design of the original experiment.

The originally assumed soil conditions have now been altered (in the light of subsequent tests). The original hypothesis can now be said to have made assumptions which turned out to be invalid for martian conditions. There is every reason that this would happen again wherever there is no prior data.


Whatever "biology technological status" is, the fact remains that the motivating issue is the assumption that life exists elsewhere, with the paramount question being, "is it independent of Earth life?" All I meant by the term was the current state of equipment/technology necessary for concluding 'life'.

Your second statement is a philosophical question .. and can only be answered when and if life elsewhere has been detected. Science has nothing to say unless/until that time comes.


Here's an interesting proposal to detect ET life in situ: MICROBIAL FUEL CELLS APPLIED TO THE METABOLICALLY -
BASED DETECTION OF EXTRATERRESTRIAL LIFE (http://arxiv.org/ftp/arxiv/papers/1006/1006.1585.pdf).Seems very formulaic as it assumes life can be explicitly defined in order for this test to work. It would thus be subject to the same (or worse) risk of a 'non-result', as Voyager's Viking's suite of tests were ...

Selfsim
2013-Dec-05, 10:07 PM
Its a pity DonJ wounded himself in action (on a lost cause EU matters).

He kept me honest about Viking/Levin details :).
Which is helpful, because the Viking experiments were quite complex and very methodical in their approach and closed a lot off a lot of 'possible' interpretations. The initial motivation behind the mission however, reminds us of the folly of pursuing a search under the belief that speculation somehow has a bearing on physical reality .. which of course, it doesn't (this has now been demonstrated).

TooMany
2013-Dec-05, 11:24 PM
Most experiments that scientist perform involve a speculated outcome. If the outcome was a certainty, what would be the point of the experiment?

There is no folly here. They did an experiment based on what we do know about the mechanisms of life on earth and the results were ambiguous, i.e. inconclusive. The hypothesis of the experiment is that there may be life on Mars, similar in some ways to earth life. That is a speculation but testing that hypothesis is what is called science not folly. If there are unexpected chemicals on the surface that caused the results, then that is also new knowledge derived from the experiment even though if failed to definitively find life.

Selfsim
2013-Dec-06, 12:19 AM
… If there are unexpected chemicals on the surface that caused the results, then that is also new knowledge derived from the experiment even though if failed to definitively find life.The knowledge of perchlorates (for eg) didn't come from Viking's results .. it came from Phoenix onwards. These tests were designed for general soil chemistry analysis ... not the more specific life tests.

This demonstrates the priority of testing needed before any conclusions can be reached about sparse microbial life presence (or not). All those other variables have to be constrained by geochemical data buildup, in order for a 'life' conclusion to remain. Its a process of elimination, because of life's composition coming from extant geochemistry. This is all predicated on a model of what is thought to exist in a given environment however, (along the lines of thinking outlined in A.DIM's OP).

If an obvious alien licked the lens on Curiosity however, (and was photographed in the act), well, that would be a different story though, eh?

TooMany
2013-Dec-07, 07:03 AM
The knowledge of perchlorates (for eg) didn't come from Viking's results .. it came from Phoenix onwards. These tests were designed for general soil chemistry analysis ... not the more specific life tests.

The presence of oxidizers on the surface was claimed to account for the Viking results. I believe that peroxides were suggested at the time. (I said "unexpected chemicals" not perchlorates BTW.)


This demonstrates the priority of testing needed before any conclusions can be reached about sparse microbial life presence (or not). All those other variables have to be constrained by geochemical data buildup, in order for a 'life' conclusion to remain. Its a process of elimination, because of life's composition coming from extant geochemistry. This is all predicated on a model of what is thought to exist in a given environment however, (along the lines of thinking outlined in A.DIM's OP).

We rarely do experiments in which we KNOW that all possibilities are taken into account. When you prepare an experiment costing billions of dollars you have neither the time nor money to carefully test for every possible alternative prior to formulating your experiment. That criticism of the experiment is completely unfounded but motivated by what?


If an obvious alien licked the lens on Curiosity however, (and was photographed in the act), well, that would be a different story though, eh?

Good grief. I don't think so. Most likely an alternative explanation would be found for the appearance of a tongue licking the lens.

A.DIM
2013-Dec-09, 04:10 PM
For one, a several million year shorter transport time. For another, softer landings... and launches. A brief exposure to vacuum and radiation is not the same as Riding The Wild Meteoroid for eons, with an Earth Shattering Kaboom at either end.

Im rather sure its been shown that impact, ejection, exposure are survivable. Its the transit time which raises doubt. However, only a couple years ago we discussed Dynamics of escaping Earth ejecta , wherein the modelling shows material reaching Venus, Mars, and Jupiter (its moons) fairly rapidly, on the order of tens of thousands of years, not millions. That seems more doable for life.



Er, then how do you tell which microbes you're detecting?

Er do we assume Earth microbes can survive the conditions wherever our craft go? If not, why should we detect Earth microbes in the experiments once there? If Earth life can survive the conditions elsewhere, so as to be detected in the experiments, what precludes the likelihood life has transported naturally, many times over? Never mind that not one spacecraft sent from Earth has been completely sterile

Noclevername
2013-Dec-09, 04:16 PM
I’m rather sure it’s been shown that impact, ejection, exposure… are survivable.

[citation needed]


Er … do we assume Earth microbes can survive the conditions wherever our craft go? If not, why should we detect Earth microbes in the experiments once there? If Earth life can survive the conditions elsewhere, so as to be detected in the experiments, what precludes the likelihood life has transported naturally, many times over? Never mind that not one spacecraft sent from Earth has been completely sterile …

I don't understand. How does that answer my question about how to distinguish the origin of microbes?

A.DIM
2013-Dec-09, 04:19 PM
No .. the results were contradictory when viewed from the hypothesis which drove the design of the original experiment.

The originally assumed soil conditions have now been altered (in the light of subsequent tests). The original hypothesis can now be said to have made assumptions which turned out to be invalid for martian conditions. There is every reason that this would happen again wherever there is no prior data.

No. The results were consistent with biological activity, as laid out in pre mission criteria. The design of the LR experiment was based on a Standard Method for detecting microbes still used widely today (and not one instance of a “false positive”). The only real difference is that Levin added organic nutrients found in Miller –Urey experiment and tagged the solution with C14 to expedite things. But don’t take it from me, take it from Levin himself, earlier this year: Implications of Curiosity’s Findings … LR Experiment .. Life on Mars (http://www.gillevin.com/Mars/SPIE_2013_Revised.pdf).


All I meant by the term was the current state of equipment/technology necessary for concluding 'life'.

Your second statement is a philosophical question .. and can only be answered when and if life elsewhere has been detected. Science has nothing to say unless/until that time comes.

My question has nothing to do with philosophy. It is a question to be answered empirically, and is a question which informs current exploratory efforts. Again, what are the best reasons to think, if and when life is found elsewhere, said life might possibly be of independent origin?


Seems very formulaic as it assumes life can be explicitly defined in order for this test to work. It would thus be subject to the same (or worse) risk of a 'non-result', as Voyager's suite of tests were ...

Seems rather novel to me; a potential way of discovering ET life in situ.
Defining “life” is no doubt fraught with difficulty but metabolism, I’d think, is a fairly good indicator.
And to what "non result" from Voyager are you referring?

A.DIM
2013-Dec-09, 04:40 PM
[citation needed]

Really?
There's plenty to be found (including under A.DIM's started threads over the past decade), but here are a couple to get you started: Natural Transfer of Viable Microbes in Space (http://www.sciencedirect.com/science/article/pii/S0019103599963170).

Survival of bacteria and spores under extreme shock pressures (http://adsabs.harvard.edu/full/2004MNRAS.352.1273B).


I don't understand. How does that answer my question about how to distinguish the origin of microbes?

I said sterilization is not necessary.
You asked how we tell apart any found microbes.

Are you assuming earth borne microbes will survive to be detected by the experiments?
Or are you assuming sterilization efforts are effective enough so as to allow experiments to identify an independent lineage of life, the holy grail?

Noclevername
2013-Dec-09, 05:24 PM
Really?
There's plenty to be found (including under A.DIM's started threads over the past decade), but here are a couple to get you started: Natural Transfer of Viable Microbes in Space (http://www.sciencedirect.com/science/article/pii/S0019103599963170).

Survival of bacteria and spores under extreme shock pressures (http://adsabs.harvard.edu/full/2004MNRAS.352.1273B).

Listing links is not proper citation, please explain in your own words what you find convincing about the existing evidence.

EDIT: I'll be blunt, your previous threads have failed to make me think it likely for life to have been spread by meteor. If your reply is more of the same, it's probably not going to work the 101st time you try it either..




Are you assuming earth borne microbes will survive to be detected by the experiments?
Or are you assuming sterilization efforts are effective enough so as to allow experiments to identify an independent lineage of life, the holy grail?

I'm assuming nothing. I'm asking HOW CAN YOU TELL if the microbes you examine are Earth microbes that survived, descendants of long-ago Earth microbes, or native microbes?

A.DIM
2013-Dec-09, 07:32 PM
Listing links is not proper citation, please explain in your own words what you find convincing about the existing evidence.

EDIT: I'll be blunt, your previous threads have failed to make me think it likely for life to have been spread by meteor. If your reply is more of the same, it's probably not going to work the 101st time you try it either..

What’s the saying, you can lead a horse to water … ?

You asked for cites supporting my own words, “impact, ejection, exposure … are survivable.” And that’s what you got: links to peer reviewed science supporting what I say. Whether or not you think it likely, it’s an active area of research for scientists who do, and is why we continue to see such models and experiments.


I'm assuming nothing. I'm asking HOW CAN YOU TELL if the microbes you examine are Earth microbes that survived, descendants of long-ago Earth microbes, or native microbes?

You assume there could be a difference between “earth microbes, long lost cousins, or natives," no? I do not. I think any life discovered will be found to be of similar cosmic ancestry, and so expecting to tell them apart is misguided, time consuming and expensive.

Answer my questions please?
And again, as well, what are the best reasons to assume there could be life of independent origin in our solar system?

R.A.F.
2013-Dec-09, 10:57 PM
And again, as well, what are the best reasons to assume there could be life of independent origin in our solar system?

That is, assuming that there is any other life in our SS....a rather large assumption.

Selfsim
2013-Dec-09, 11:05 PM
No. The results were consistent with biological activity, as laid out in pre mission criteria. The design of the LR experiment was based on a Standard Method for detecting microbes still used widely today (and not one instance of a “false positive”). The only real difference is that Levin added organic nutrients found in Miller –Urey experiment and tagged the solution with C14 to expedite things. But don’t take it from me, take it from Levin himself, earlier this year: Implications of Curiosity’s Findings … LR Experiment .. Life on Mars (http://www.gillevin.com/Mars/SPIE_2013_Revised.pdf). You are only focussing on Levin's LR experiment. This was not the whole experiment. The Viking GCMS detected no organics and was subsequently demonstrated to be incapable of detecting sparse, low level soil organics.
The ambiguous conclusion is formed when looking across the full array of tests done (GEX, PR, LR, GCMS, etc, etc) ... all of which were originally intended to constrain the variables allowing for a microbial life detection conclusion. The concentration levels of that speculated life, in certain concentrations of extant oxidisers caught out the whole Viking life detection experiment. It also serves as an exclamation point for the futility of over-designing an experiment when one has no data whatsoever, to expect its subject matter to be present in the first place!


My question has nothing to do with philosophy. It is a question to be answered empirically, and is a question which informs current exploratory efforts.Name one experiment sent to another body in the solar system, which has been capable of discriminating between Earth life and life not originating from Earth.


Again, what are the best reasons to think, if and when life is found elsewhere, said life might possibly be of independent origin? Who cares about what might be 'the best' speculated reasons?
It makes no difference until there is some 'sample of interest'!


Seems rather novel to me; a potential way of discovering ET life in situ. Defining “life” is no doubt fraught with difficulty but metabolism, I’d think, is a fairly good indicator.Levin's LR experiment was 'novel' too, when it came to applying it on martian soil. It also used metabolism as its detection basis.
What was the end result of the complete suite of life tests? Ambiguity!
Metabolism detection requires the elimination of other environmental variables, (or empirically well-constrained variables), in order to decide whether what the experiment is measuring, is bio-metabolism or some other complex inorganic process!

The test was incomplete and the focus was subsequently put on the GCMS instrument to dig it out of the ditch. If it was a complete test, Levin should have closed any loopholes leading to ambiguity (beyond just 'his' experiment). It may be unreasonable to expect Levin to have done this when it was being designed, but it is now reasonable to expect this in a modern-day experiment.


And to what "non result" from Voyager are you referring?The combined LR, GEX, PR and GCMS experiments (see above). EDIT: Viking ... not Voyager.

Noclevername
2013-Dec-09, 11:31 PM
What’s the saying, you can lead a horse to water … ?

You asked for cites supporting my own words, “impact, ejection, exposure … are survivable.” And that’s what you got: links to peer reviewed science supporting what I say. Whether or not you think it likely, it’s an active area of research for scientists who do, and is why we continue to see such models and experiments.

I asked for your interpretation of EVIDENCE, something I have yet to see.



You assume there could be a difference between “earth microbes, long lost cousins, or natives," no? I do not. I think any life discovered will be found to be of similar cosmic ancestry, and so expecting to tell them apart is misguided, time consuming and expensive.


There are differences between all species. We can tell in Earth organisms roughly how long ago they shared a common ancestor. Yet you think there's "no difference"?

If you really believe that claim I have nothing to say that would convince you.


Answer my questions please?

I did.


And again, as well, what are the best reasons to assume there could be life of independent origin in our solar system?

There is no reason to assume anything. That is the problem with your statements.

This conversation is clearly pointless, it's just a re-run of old news. I'm done.

R.A.F.
2013-Dec-09, 11:44 PM
Who cares about what might be 'the best' speculated reasons?
It makes no difference until there is some 'sample of interest'!

Agreed....until there is a sample, this could be characterized as putting the cart before the horse...in my opinion.

Van Rijn
2013-Dec-10, 02:01 AM
However, the factors noted in the article you linked hold true whether the prospective life we search for is native or a long-lost cousin-- either way, bringing along our own present-day germs could yield a false positive for ETL. So what procedural differences would you introduce?

And along with the importance to experimental testing, it is just the responsible thing to do. We have a great deal of experience with the introduction of foreign species to an ecosystem, and how they can wipe out native species. If there's anything like that on Mars, I wouldn't want to be involved in its unnecessary destruction. Also, if ETs ever did visit Earth, I'd hope they'd show the same consideration for us.

Selfsim
2013-Dec-10, 05:28 AM
Agreed....until there is a sample, this could be characterized as putting the cart before the horse...in my opinion.Yep .. good catch ... I wasn't attempting to devalue anyone's 'opinion' ... they're perfectly entitled to have one ... what I meant was that scientifically speaking, there is nothing to say until the observational/measurement data exists. Opinions are optional. Once a sample of interest has caught an explorer's attention, tests can be developed from whatever it is that caught the explorer's attention. Sending tests in advance of that event, in the light of not knowing whether or not there is something in a place, is a big 'hit and miss'. This is surely what Viking's life tests taught us!

A.DIM and all:
It seems I've also been typing "Voyager" when I've been meaning "Viking" ... apologies for the error.

A.DIM
2013-Dec-10, 05:53 PM
You are only focussing on Levin's LR experiment. This was not the whole experiment. The Viking GCMS detected no organics and was subsequently demonstrated to be incapable of detecting sparse, low level soil organics.
The ambiguous conclusion is formed when looking across the full array of tests done (GEX, PR, LR, GCMS, etc, etc) ... all of which were originally intended to constrain the variables allowing for a microbial life detection conclusion. The concentration levels of that speculated life, in certain concentrations of extant oxidisers caught out the whole Viking life detection experiment. It also serves as an exclamation point for the futility of over-designing an experiment when one has no data whatsoever, to expect its subject matter to be present in the first place!

Given what we know today about extremophiles and the environs on Mars today, the Viking results are entirely consistent with biological activity. The GEX, PR and LR experiments all returned results which could be due to biological activity. It was GCMS that was appointed “arbiter” of the findings and thus, with it detecting no organics, a “no life” conclusion was drawn. Of course, as you point out, it has been shown that the GCMS experiment wouldn’t have detected the low levels of organics to begin with. With this in mind, it would appear the Viking experiments did find life.


Name one experiment sent to another body in the solar system, which has been capable of discriminating between Earth life and life not originating from Earth.

There are none; That’s not what I said or implied.


Who cares about what might be 'the best' speculated reasons?
It makes no difference until there is some 'sample of interest'!

If it makes no difference then what’s the point in “sterilizing” spacecraft?
No doubt, it is the scientists involved in such research who care the most, but I care too. So can you give me one good reason to think, if and when life is found elsewhere, that life could be of separate genesis / lineage?


Levin's LR experiment was 'novel' too, when it came to applying it on martian soil. It also used metabolism as its detection basis.
What was the end result of the complete suite of life tests? Ambiguity!
Metabolism detection requires the elimination of other environmental variables, (or empirically well-constrained variables), in order to decide whether what the experiment is measuring, is bio-metabolism or some other complex inorganic process!

The test was incomplete and the focus was subsequently put on the GCMS instrument to dig it out of the ditch. If it was a complete test, Levin should have closed any loopholes leading to ambiguity (beyond just 'his' experiment). It may be unreasonable to expect Levin to have done this when it was being designed, but it is now reasonable to expect this in a modern-day experiment.

The GCMS was a failed experiment as it detected no organics. This was a puzzle because Martian meteorites contain a plethora of organic materials; GCMS should have detected some. Because of this it was even suggested that sample material failed to reach the processor, and actually, there’s no incontrovertible evidence that material ever made it into the GCMS. Of course, we now know the GCMS wasn’t sensitive enough to detect organics to begin with. Why should it stand then, as the “final answer” to Viking’s ambiguous results?


The combined LR, GEX, PR and GCMS experiments (see above). EDIT: Viking ... not Voyager.

Yes, I figured that after I asked. Thanks.

A.DIM
2013-Dec-10, 06:14 PM
I asked for your interpretation of EVIDENCE, something I have yet to see.

Then you’re ignoring the many studies I’ve cited which support my words that “impact, ejection, exposure … are survivable.”


There are differences between all species. We can tell in Earth organisms roughly how long ago they shared a common ancestor. Yet you think there's "no difference"?

If you really believe that claim I have nothing to say that would convince you.

At the biochemical level, virtually all life is identical. The “differences” you see are largely morphology.


I did.

No, you didn’t. You asked “HOW CAN YOU TELL?” between Earth microbes and those potentially found elsewhere. With this question, you assume there’s a chance of discovering a separate lineage / genesis.
So, do you think sterilization efforts are necessary?


There is no reason to assume anything. That is the problem with your statements.

I assume then, you view it as a problem for the scientists who assume spacecraft should be "sterilized" against contamination so as to retain hope for finding the holy grail?
Do you agree or disagree with their assumption?


This conversation is clearly pointless, it's just a re-run of old news. I'm done.

My grandmother used to say, "Turkeys are done, people are finished," but I'm sad to see you withdraw nonetheless.

What's new news here is the study, the science, supporting lithopanspermia via the Chicxulub impact event.

R.A.F.
2013-Dec-10, 07:40 PM
Then you’re ignoring the many studies I’ve cited which support my words that “impact, ejection, exposure … are survivable.”

Those "studies" are not evidence...which is what Noclevername asked for...

Of course you can not be compelled to present evidence supporting your opinion, but there is no rule saying that Noclevername can't "ask". :)

Van Rijn
2013-Dec-10, 08:15 PM
If it makes no difference then what’s the point in “sterilizing” spacecraft?
No doubt, it is the scientists involved in such research who care the most, but I care too. So can you give me one good reason to think, if and when life is found elsewhere, that life could be of separate genesis / lineage?


Seriously? Because within the boundaries of current scientific knowledge it is one of the possibilities (which I think should be an obvious point). Abiogenesis is still a wide open research subject, and nobody has established that there is only a single possible abiogenesis process with very specific results.

That seems to me like asking why planets could be different, have different environments, etc.

Selfsim
2013-Dec-10, 08:23 PM
… If it makes no difference then what’s the point in “sterilizing” spacecraft?
No doubt, it is the scientists involved in such research who care the most, but I care too. So can you give me one good reason to think, if and when life is found elsewhere, that life could be of separate genesis / lineage? As has been pointed out, sterilisation helps to minimise Earth-sourced bio-organics .. thereby controlling another experimental variable which could lead to a false positive. When any specific life test is incorporated into a probe, as far as empirical science is concerned it represents a test of the hypothesis that: "life may occur elsewhere". This is 'the hump' they are trying to get over … not: "given that life occurs elsewhere, life may not be related to Earth-life". The latter hypothesis leap-frogs 'the hump'. First things first.


The GCMS was a failed experiment as it detected no organics. This was a puzzle because Martian meteorites contain a plethora of organic materials; GCMS should have detected some. Because of this it was even suggested that sample material failed to reach the processor, and actually, there’s no incontrovertible evidence that material ever made it into the GCMS. Of course, we now know the GCMS wasn’t sensitive enough to detect organics to begin with.Well, it was sensitive enough to detect higher microbe counts than are found in the Atacama tests. From that perspective, it wasn't necessarily 'a failed test'.

More interesting than arguing opinions; the SAM/Curiosity results for organic testing at John Klein and Cumberland were released, just yesterday. The paper is here (http://authors.library.caltech.edu/42647/1/Ming_et%20al_2013_Science_Sheepbed%20Volatiles_Acc epted.pdf). I strongly recommend reading the sections: "Evolved CO2 "Organic Compounds" and "Preservation of Organics".

Two quotes summarise the SAM organics testing results as follows:
The SAM data do not allow us to prove, or disprove, organic C contributions from Sheepbed to evolved chlorinated hydrocarbons and CO2 from the JK and CB samples. There are no conclusive EGA or GCMS observations of other organic molecules indigenous to the Sheepbed mudstone.
...
The complicated story of carbon on Mars is poorly understood. As of sol 370, SAM results support the presence of carbon source(s) in samples from the Sheepbed mudstone that contribute(s) to the production of chlorinated hydrocarbons and evolved CO2. There may be organic matter in these samples, but it has not been confirmed as martian.That is the current state of knowledge.

The point here is that even with the 'state of the art' remote geochemical testing equipment, the level(s) of martian surface organics is proving to be extremely difficult to constrain.

Also interesting from this report, is that the cleaning products used, influence the reaction in the pre-GCMS ovens, thereby complicating extant organics detection (if present). If the aim is microbial life detection, then they need to find some way of minimising the cleaning product-contamination! Of course, looking specifically for Earth-like microbes is an ideologically based search in the first place … ie: the ideology is where the problem originates.

All I can say is "What a troubled web we weave .. when we set out to deceive" ourselves by convincing ourselves that life should exist on Mars, when there is absolutely no data supporting that contention in the first place!

Van Rijn
2013-Dec-10, 08:49 PM
Then you’re ignoring the many studies I’ve cited which support my words that “impact, ejection, exposure … are survivable.”


I remember several points that we have previously discussed when you brought up various studies on this subject, and the distinctions with Mars landers/rovers.

Such as: The Earth's escape velocity is over twice that of Mars, requiring more extreme (less survivable) events for Earth to Mars than Mars to Earth.

From one of the probabilistic studies you presented, it showed that only a small fraction of the material from an Earth event would reach Mars, and the transfer time for most of it would be in the millions of years (a small percentage would be in the tens/hundreds of thousands of years range).

DNA accumulates damage over time, even in radiodurans spores (its DNA repair abilities only function when it is active). The shortest transfer times are long for anything to remain viable.

Most species require biological material from other species to survive, because it's cheaper to specialize. So it isn't enough for a species just to be able to survive a long period as a spore. There either needs to be a sufficient mix of surviving species, or non-specialists that can survive just with a mix of chemicals.

They also need to reach a compatible environment to grow.

In the case of a lander/rover, the rough launch and landings are sidestepped, the travel time is radically shorter than what would be possible for material from an impact event, and we tend to put them in areas we think are conducive to life. We also give them the ability to dig into the ground into areas that could present a better environment than just the surface.

So this is a substantially different situation than possible impact transfer.

Incidentally, the reason for minimizing the bio-load is to make it less likely for non-specialist microbes or a sufficient mix of microbes to reach an environment where they can grow. The minimization is still important even if not perfect. It's also important to avoid or take some care with the areas thought most likely to be able to support life.

MaDeR
2013-Dec-12, 08:44 PM
I think any life discovered will be found to be of similar cosmic ancestry, and so expecting to tell them apart is misguided, time consuming and expensive.
Evolution would ensure differences between microbes that were present in different conditions (space and surface of Earth are VERY different environment), not to mention different ancestry, indepedent abiogenesis etc. It would be relatively easy to tell them apart.

Resignation from telling apart microbes and claims everything is basically same thing is just excuse to present Earth microbes found very high in atmosphere as "microbes from outer space" and other disortion of science. Nope.

For example, let's get some future, life-finding mission to Mars that drills deep - dozen of meters - into water-bearing rock on site known for generating methane. After analysis of samples, we find microogranisms that are identical to known hardy bacteria that sometimes can survive less extensive sterilising cleaning procedures of spacecraft.

Scientists will conclude it was contamination of drill from parts of spacecraft that were not as thoroughly sterilized.

Pseudoscientists like Wickramasinghe will, of course, herald it as alien life that just happens to be identical to known Earth bacteria. Laughable.

Selfsim
2013-Dec-13, 06:20 AM
Evolution would ensure differences between microbes that were present in different conditions (space and surface of Earth are VERY different environment), not to mention different ancestry, indepedent abiogenesis etc. It would be relatively easy to tell them apart.Dissimilar evolutionary micro-environments correlated with the respective Earth-microbe domains didn't alter the core basis of their common genetic model elements, nor the core basis of a common metabolism. If asteroid dwelling microbes (for eg) were not to meet critical population reproduction rates, then evolution in a space environment would not account for significant deviations from the core basis of the common model, either. (If such a deviation were to be ever measured in a 'sample of interest' found elsewhere, that is).


For example, let's get some future, life-finding mission to Mars that drills deep - dozen of meters - into water-bearing rock on site known for generating methane. After analysis of samples, we find microogranisms that are identical to known hardy bacteria that sometimes can survive less extensive sterilising cleaning procedures of spacecraft.

Scientists will conclude it was contamination of drill from parts of spacecraft that were not as thoroughly sterilized.Well that opinion is based on your assumption of what correlated observations might be made, alongside what might be discovered, (if anything were to be discovered at all, that is). What if the discovered sub-surface, genotypically identical martian bacteria, also happened to cluster (visibly) into lip-licking, mobile, purple colonies? Let's see somthin' like that hangin' off the end of a drill bit evading pre-launch 'quarantine' inspections!

Both these lines of argument are pointless until there is some empirically sourced constraining data to corral the wild imaginations and opinions.

eburacum45
2013-Dec-13, 11:51 AM
Dissimilar evolutionary micro-environments correlated with the respective Earth-microbe domains didn't alter the core basis of their common genetic model elements, nor the core basis of a common metabolism. If asteroid dwelling microbes (for eg) were not to meet critical population reproduction rates, then evolution in a space environment would not account for significant deviations from the core basis of the common model, either.I do not think this is necessarily the case. If a population of Earth-microbes were to be established in an alien environment it would become increasingly distinguishable from the population on Earth. Silent substitution of the genetic material might allow a fairly reliable measure of how many million years the two populations have been separated, unless there is a mechanism in the population that resists genetic change.
from here
http://link.springer.com/article/10.1007%2FBF02111283

The average substitution rate for 16S rRNA in eubacteria is about 1%/50 Myr, similar to the average rate for 18S rRNA in vertebrates and flowering plants.
Maybe the sort of Earth microbes that are likely to survive in such locations would be more likely to include a mechanism that resists such gradual change, but until we find such a population we won't know for sure.

Selfsim
2013-Dec-13, 09:00 PM
I do not think this is necessarily the case. If a population of Earth-microbes were to be established in an alien environment it would become increasingly distinguishable from the population on Earth. Silent substitution of the genetic material might allow a fairly reliable measure of how many million years the two populations have been separated, unless there is a mechanism in the population that resists genetic change.Well, I agree that in general, silent random mutations might result in functional substitutions, which could then be used as a basis for distinguishing between Earthly and space-living bacteria, ('delayed development' bacteria?), but once again, as I have stated throughout this thread, that all depends on the empirical nature of what's actually discovered, (if & when that might happen):

The hypothetical scenario I cited, portrayed quite a different hypothetical, ie:
If asteroid dwelling microbes (for eg) were not to meet critical population reproduction rates, then evolution in a space environment, would not account for significant deviations from the core basis of the common model, either. (If such a deviation were to be ever measured in a 'sample of interest' found elsewhere, that is).Silent mutations don't even significantly alter even the phenotype of the organism in which they occur I was speaking about the core functions ie: the common basis presently understood to be the way all life appears to function, when viewed from the common model perspective ... ie: the common polymers, the use of nucleic acids, protein catalysis, the standard genetic code (including its known variant codes), the common process steps and common energy source basis of the common metabolism). No significant changes in these core bases have ever been observed, (courtesy of any of the vast micro-environments which have ever existed throughout Earth's history), in spite of the mechanism you mention, and in spite of Evolution's ability to explain other variations. If such changes were to be found anywhere where life is present, then Evolutionary explanations would be up against a vast amount of contradictory evidence, coming from its very own Earthly support basis. Remember Evolution is based, (so far), on a necessarily, Earth-centric model of life, which assumes replication and heritability. Recent findings on organism dormancy and; finite-span, apparent 'immortality' with encoded repair mechanisms, might well rule out Evolutionary and mutation based explanations for certain classes of 'hypothetically possible', non-Earth based discoveries in certain conceivable micro-habitats, (if & when, that were ever to happen). Who knows? Oh, hang on ... some folk already do know ... that's right .. its 'Unknown' ('Yeah .. let's just skip over that tiny finding shall we, eh?')

Now I'll be bold in presuming that this opinion-based discussion will 'likely' turn to "But how 'likely or unlikely' is such a scenario?" .. which would then become even more meaningless when discussing hypothetical, non-Earth based discoveries.

The point I'm making here is that we can all go on making up hypothetical scenario/counter scenarios until we're blue in the face .. it makes no difference on the future. Theories like Evolution, or hypotheses like Panspermia, do not determine a certain future. They have never been intended for that purpose, and using them in such a way has nothing to do with science. All that's about is 'winning' some meaningless argument nothing more.

eburacum45
2013-Dec-13, 10:03 PM
... the common basis presently understood to be the way all life appears to function, when viewed from the common model perspective ... ie: the common polymers, the use of nucleic acids, protein catalysis, the standard genetic code (including its known variant codes), the common process steps and common energy source basis of the common metabolism). No significant changes in these core bases have ever been observed, (courtesy of any of the vast micro-environments which have ever existed throughout Earth's history), in spite of the mechanism you mention, and in spite of Evolution's ability to explain other variations.
Hmm. The core base processes can't be entirely immutable, otherwise the 'known variant codes' would not have emerged either.

But you have a point, of sorts; the 'deep hot biosphere' on Earth has recently been found to be surprisingly uniform.
http://www.newscientist.com/article/dn24727-the-19-superbugs-that-rule-earths-hidden-depths.html#.UquDW-KAkud
If bacteria have colonised widely separated deep locations on the Earth and remained recognisably similar after having presumably been separated for millions or billions of years, then the same could possibly occur in space.

Selfsim
2013-Dec-13, 10:41 PM
Hmm. The core base processes can't be entirely immutable, otherwise the 'known variant codes' would not have emerged either.There are theoretical physical chemistry constraints .. but these are still way too broad, given the theoretically possible permutation space evident in the model.


But you have a point, of sorts; the 'deep hot biosphere' on Earth has recently been found to be surprisingly uniform.
http://www.newscientist.com/article/dn24727-the-19-superbugs-that-rule-earths-hidden-depths.html#.UquDW-KAkud
If bacteria have colonised widely separated deep locations on the Earth and remained recognisably similar after having presumably been separated for millions or billions of years, then the same could possibly occur in space.The point is that the matter cannot be resolved in theory, with 'thought experiments', or with the available empirical evidence ... that's what 'unknown' means ... the problem is not constrained by data.

A.DIM
2013-Dec-16, 03:18 PM
Hi All.
Haven't had time to engage lately but reading your comments (some good points are made!) it occurs to me that others may not have read the paper itself (http://online.liebertpub.com/doi/pdf/10.1089/ast.2013.1028), wherein some of these questions / objections are addressed.

The final point, I think, is that material exchange in our solar system is fact, occurring more readily and reaching more places than previously thought. Earth impacts have no doubt flung material across the system with life aboard. Thus, life and or life's detritus have already reached all the places we might otherwise find life.
IMO, hope for finding a separate lineage then, is misguided, costly and time consuming.

R.A.F.
2013-Dec-16, 03:23 PM
The final point, I think, is that material exchange in our solar system is fact...

Material exchange is fact...life exchange is not.


Just keeping you "honest" :D

Serious Matters
2013-Dec-16, 08:56 PM
No .. the results were contradictory when viewed from the hypothesis which drove the design of the original experiment.

The originally assumed soil conditions have now been altered (in the light of subsequent tests).

What subsequent tests...do you mean at the Viking(s) landing sites?


The original hypothesis can now be said to have made assumptions which turned out to be invalid for martian conditions. There is every reason that this would happen again wherever there is no prior data.

If that was the case, then all instruments would have provided negative results.I have read somewhere that it was demonstrated that the Vinking GCMS was unable to detect organic compounds with some Antarctica Earth samples -proved- to have a very low microorganisms population in the samples.



All I meant by the term was the current state of equipment/technology necessary for concluding 'life'.

Seems very formulaic as it assumes life can be explicitly defined in order for this test to work. It would thus be subject to the same (or worse) risk of a 'non-result', as Voyager's Viking's suite of tests were ...

Then, what kind of life detection experiments do you propose?

Selfsim
2013-Dec-17, 07:16 AM
Well, hello there, 'Serious Matters'!
Welcome to the "If...Then...Else... Maybe... Likely...Unlikely...Speculation Forum"!
I'm not sure we deal with serious matters in this forum, though(?) ...

What subsequent tests...do you mean at the Viking(s) landing sites?No actually .. I meant the Atacama and Antarctica samples taken to produce the Navarro-Gonzales report, (~40 years later).

If that was the case, then all instruments would have provided negative results.You think? ...
... How come?

I have read somewhere that it was demonstrated that the Vinking GCMS was unable to detect organic compounds with some Antarctica Earth samples -proved- to have a very low microorganisms population in the samples.Yep .. as per the Navarro-Gonzales report.

Then, what kind of life detection experiments do you propose?That would depend entirely on the nature of 'the find', (or 'sample of interest').

A visual inspection for unusual things for that landscape would seem to be the first 'detection step', no?

iquestor
2013-Dec-17, 11:25 AM
NoCleverName said:
EDIT: I'll be blunt, your previous threads have failed to make me think it likely for life to have been spread by meteor.



I wonder... taking what we know of the KT Event impact, or any impact large enough to throw earth rocks into space, could we somehow model and predict the likelihood of debris from the impact making it to other planetary bodies in our solar system?

I'm not suggesting we could mathematically prove that a rock from the KT Impact landed on Europa, per se. What I'm after is, if we know the force of the KT impact, and where it hit (Yucatan Peninsula), and roughly when it hit (64MYO), and the makeup of the rocks, etc that were part of the impact, could we then model the impact with reasonable data on ejection velocities, angles of ejection, size of ejecta, time in transit, probability of crossing this or that planetary bodies gravity well, etc, and get an educated idea of the probability that some of the ejecta could have ended up on other bodies in the solar system?

Serious Matters
2013-Dec-17, 07:45 PM
Well, hello there, 'Serious Matters'!
Welcome to the "If...Then...Else... Maybe... Likely...Unlikely...Speculation Forum"!
I'm not sure we deal with serious matters in this forum, though(?) ...
No actually .. I meant the Atacama and Antarctica samples taken to produce the Navarro-Gonzales report, (~40 years later).
.....
Yep .. as per the Navarro-Gonzales report.

Hi!
From the the Navarro-Gonzales report
Conclusions


Our results influence the interpretation of the Viking TVGCMS data. The fact that no organic molecules were released by this analytical treatment during the analysis of the Mars soils does not demonstrate that there were no organic materials on the surface of Mars because it is feasible that they were too refractory to be released at the temperatures achieved or were oxidized during the TV step by the iron present in the soil. The release of 50700 ppm of CO2 by TV from 200C to 500C in the Viking analysis (2) may indicate that an oxidation of organic material took placed.

That seem to gives more credence to the LR results rather than negate them.


That would depend entirely on the nature of 'the find', (or 'sample of interest').

A visual inspection for unusual things for that landscape would seem to be the first 'detection step', no?

Green patches on rocks were observed by Viking as well as by Curiosity low resolution Mastcam.One wonder why the Curiosity team have not used the high resolution cam and the chem cam for further analysis?

About that and more, i just find that Gilbert Levin think that NASA may hide some infos,
FOIA to NASA Headquarters filed Dec. 9, 2013 by GV Levin.
http://www.gillevin.com/Mars/FOIA_TO_NASA_HEADQUARTERS.pdf

Selfsim
2013-Dec-18, 06:38 AM
... That seem to gives more credence to the LR results rather than negate them.Its still possible there's organics in the soil/rock tailings, but my point has been that the full suite of Viking Life detection tests, (GEX, LR, GCMS, PR), has only resulted in a bunch of explanations, all targetted at explaining why the net results were as they were ... and if one accepts that no instruments malfunctioned, then there seems to be only two possible conclusions: Either the samples tested contained completely unanticipated contents, (or concentrations of them), or the experimental procedure, was not appropriate for detecting or excluding what may or may not be present there. These are the risks one takes when one 'goes in' assuming one 'knows all' about 'the life target environment', around which the experiments have been specifically designed.

Firstly as part of those explanations, it has been subsequently found that the GCMS was not designed to detect extremely low levels of organics (for the case of low microorganism counts). Secondly, the GCMS T-V process was not appropriate for revealing or excluding the anticipated target. A wet chemistry process is now known to be more appropriate (if the assumed target exists). Thirdly, the effects of soil oxidants was not taken into consideration because the presence of these was not known prior to Viking. Fourthly, UV irradiation is thought to have destroyed any surface organics anyway.

Note that all of these 'explanations' do not also preclude the possiblity that there simply isn't any bio-organics on Mars, either.

Now, why wouldn't the same situation happen again, if life testing is conducted a priori on some other local object?


Green patches on rocks were observed by Viking as well as by Curiosity low resolution Mastcam.One wonder why the Curiosity team have not used the high resolution cam and the chem cam for further analysis?Well they announced just recently that Chemcam has just passed its 100,000 firings count! (http://phys.org/news/2013-12-martian-laser-surpasses-zaps.html) ... And plenty of hi-res photos (& spectra) have been taken ...

A.DIM
2013-Dec-18, 03:57 PM
NoCleverName said: I wonder... taking what we know of the KT Event impact, or any impact large enough to throw earth rocks into space, could we somehow model and predict the likelihood of debris from the impact making it to other planetary bodies in our solar system?

I'm not suggesting we could mathematically prove that a rock from the KT Impact landed on Europa, per se. What I'm after is, if we know the force of the KT impact, and where it hit (Yucatan Peninsula), and roughly when it hit (64MYO), and the makeup of the rocks, etc that were part of the impact, could we then model the impact with reasonable data on ejection velocities, angles of ejection, size of ejecta, time in transit, probability of crossing this or that planetary bodies gravity well, etc, and get an educated idea of the probability that some of the ejecta could have ended up on other bodies in the solar system?

I can't get away from taking this as rhetorical ...
The paper in question is exactly what you're asking about.
Additionally, there's a thread called "Dynamics of escaping ejecta ... " wherein other such studies are presented.

A.DIM
2013-Dec-18, 04:03 PM
Hi!
From the the Navarro-Gonzales report... Conclusions

That seem to gives more credence to the LR results rather than negate them.

Hello Serious Matters, welcome to the forum!

Indeed it does!

As I pointed out earlier, the GCMS was ultimately used as arbiter for the “ambiguous” results of the other tests (positive for biologic activity but coupled with some weird high energy chemistry). Therefore, the “no organics thus no life” conclusions drawn from the Viking suites no longer stand as evidence against the positive results of the other experiments. Either the GCMS was not sensitive enough to detect organics, or it destroyed them.
Throw the more recently discovered perchlorates into the mix and Viking found organics on Mars, experiment confirms (http://news.discovery.com/space/history-of-space/viking-mars-organics-experiment.htm).

"Contrary to 30 years of perceived wisdom, Viking did detect organic materials on Mars," planetary scientist Christopher McKay, with NASA's Ames Research Center in California, told Discovery News. "It's like a 30-year-old cold case suddenly solved with new facts."
"If the Viking team had said 'Well, maybe there's perchlorate in the soil,' everybody would have said they're crazy — why would there be perchlorates in the soil? It was only by having it pushed on us by Phoenix where we had no alternative but to conclude that there was perchlorate in the soil … Once you realize it's there, then everything makes sense," McKay added.

So, pre-mission criteria were met, GCMS evidence gets thrown out as “arbiter,” new discoveries are thrown in as evidence (perchlorates, water, organics) … why is NASA not preparing a follow up experiment to falsify the proper conclusion that Viking detected biological activity?!


Green patches on rocks were observed by Viking as well as by Curiosity low resolution Mastcam.One wonder why the Curiosity team have not used the high resolution cam and the chem cam for further analysis?

About that and more, i just find that Gilbert Levin think that NASA may hide some infos,
FOIA to NASA Headquarters filed Dec. 9, 2013 by GV Levin.
http://www.gillevin.com/Mars/FOIA_TO_NASA_HEADQUARTERS.pdf

Thanks for that.
No doubt we all look forward to such hi-res imagery. It's curious indeed this has not yet been done, or if it has, that the imagery hasn't been released.

Regards!

Van Rijn
2013-Dec-19, 01:18 AM
longer stand as evidence against the positive results of the other experiments. Either the GCMS was not sensitive enough to detect organics, or it destroyed them.
Throw the more recently discovered perchlorates into the mix and Viking found organics on Mars, experiment confirms (http://news.discovery.com/space/history-of-space/viking-mars-organics-experiment.htm).

"Contrary to 30 years of perceived wisdom, Viking did detect organic materials on Mars," planetary scientist Christopher McKay, with NASA's Ames Research Center in California, told Discovery News. "It's like a 30-year-old cold case suddenly solved with new facts."
"If the Viking team had said 'Well, maybe there's perchlorate in the soil,' everybody would have said they're crazy — why would there be perchlorates in the soil? It was only by having it pushed on us by Phoenix where we had no alternative but to conclude that there was perchlorate in the soil … Once you realize it's there, then everything makes sense," McKay added.


This was also in that article:

New evidence for organics on Mars does not mean Viking found life, cautions McKay. Finding organics is not evidence of life or evidence of past life. It's just evidence for organics," he said.

That's a rather important point and should have been included in your quote.




So, pre-mission criteria were met, GCMS evidence gets thrown out as “arbiter,” new discoveries are thrown in as evidence (perchlorates, water, organics) … why is NASA not preparing a follow up experiment to falsify the proper conclusion that Viking detected biological activity?!


Obviously it isn't generally accepted that this was the proper conclusion. Also, NASA is pushing for sample return, and the point of sample return is that it allows far more detailed examination in a laboratory than could be done by robots on Mars.

Selfsim
2013-Dec-19, 02:02 AM
... So, pre-mission criteria were met, GCMS evidence gets thrown out as “arbiter,” new discoveries are thrown in as evidence (perchlorates, water, organics) … why is NASA not preparing a follow up experiment to falsify the proper conclusion that Viking detected biological activity?!They already have a laboratory up there at the moment, which is capable of detecting the kinds of organics physically capable of existing in the known conditions on the surface.

The LR experiment detected evolved Carbon isotopes (only). Such carbon based reactants are expected in an environment where:
... ionizing radiation directly breaks chemical bonds in organic molecules and other chemicals, producing a reactive pool of radicals and oxidants (e.g. OH•, H2O2, oxychlorine compounds). In the presence of mineral catalysts, these reactants can fully oxidize organic matter to CO, CO2 and carbonates or produce partially oxidized organics such as acetate, oxalates, and other carboxylates that may survive in a metastable state on Mars. If exogenous or martian organic matter survived largely intact until removal of the overlying Gillespie sandstone, it may still have degraded or oxidized during surface exposure of the sampling site to ionizing radiation. Therefore, surface exposure age is also an important variable in the preservation of organics.

Alternatively, the organics may have survived all of the martian processing that occurred naturally, only to be oxidized by oxide minerals or oxychlorine compounds at elevated temperatures in the SAM oven or, if sufficiently refractory, survive pyrolysis and pass undetected by SAM, as does most of the kerogen-like material in meteorites.In other words ... there is no need to invoke biological sources for any organics currently detected by SAM, nor the evolution products detected in the Viking LR experiment ... (Nonetheless, if they (somehow) exist there, SAM could still distinguish complex organics which we typically associate with biology in an Earthly environment).

Sorry folks, the LR experiment wasn't capable of distinguishing biologically derived organics from simpler geologically sourced organics, under the controlled conditions established by the experiment. The LR evolved gases (mentioned above), have a superior, evidence-based explanation, (unlike the biological one). The LR experiment clearly failed to account for the now-evidenced, natural geo-chemical environment on the martian surface, resulting in its inability to eliminate the scenario which is now beginning to emerge, courtesy of the slow buildup of empirically sourced knowledge of geochemical data ... (As opposed to the ideologically and emotively based 'hunt for exo-life').

Serious Matters
2013-Dec-19, 11:45 PM
Sorry folks, the LR experiment wasn't capable of distinguishing biologically derived organics from simpler geologically sourced organics, under the controlled conditions established by the experiment. The LR evolved gases (mentioned above), have a superior, evidence-based explanation, (unlike the biological one). The LR experiment clearly failed to account for the now-evidenced, natural geo-chemical environment on the martian surface, resulting in its inability to eliminate the scenario which is now beginning to emerge, courtesy of the slow buildup of empirically sourced knowledge of geochemical data ... (As opposed to the ideologically and emotively based 'hunt for exo-life').

The Viking's LR experiment was so well designed that they have envisioned that possibility.To be sure that no geo-chemical reaction was responsible for a positive result a second soil sample (control test) coming from the same spot was heated at 160 degree celsius destined to kill the living microrganisms but this was not hot enough to destroy any eventual chemicals.All control test(s) were negative thus demonstrating that the positive results obtained were not caused by a geo-chemical reaction.


..., SAM could still distinguish complex organics which we typically associate with biology in an Earthly environment).

Effectively that would be greath if NASA release some information from the High Definition Cam and the Chem Cam about these green patches on rocks observed by Curiosity low resolution MastCam and from SAM liquid extraction method used on soil samples.
As i have pointed out earlier Levin as filed a FOIA request to force NASA to release that information.
http://www.gillevin.com/Mars/FOIA_TO_NASA_HEADQUARTERS.pdf

A.DIM
2013-Dec-20, 03:49 PM
This was also in that article:

New evidence for organics on Mars does not mean Viking found life, cautions McKay. Finding organics is not evidence of life or evidence of past life. It's just evidence for organics," he said.

That's a rather important point and should have been included in your quote.

Certainly, “But if NASA had realized there were organics on Mars, there might not have been a 20-year hiatus in sending landers for follow-up studies … We might have had continuing missions," Navarro-Gonzlez told Discovery News.

This is more to the point I made: that the GCMS “evidence” usurped the positive results of the LR experiment and influenced decades of noneffort. New evidence shows this was in err, and thus the only life detection package sent off planet actually returned positive results.
So, did Viking find life?
Well, yet another study, a Complexity Analysis of the Viking Labeled Release Experiments (http://ijass.org/On_line/admin/files/2%29%28014-026%2911-030.pdf) suggests it did.
Abstract:
The only extraterrestrial life detection experiments ever conducted were the three which were components of the 1976 Viking Mission to Mars. Of these, only the Labeled Release experiment obtained a clearly positive response. In this experiment 14C radiolabeled nutrient was added to the Mars soil samples. Active soils exhibited rapid, substantial gas release. The gas was probably CO2 and, possibly, other radiocarbon-containing gases. We have applied complexity analysis to the Viking LR data. Measures of mathematical complexity permit deep analysis of data structure along continua including signal vs. noise, entropy vs. negentropy, periodicity vs. aperiodicity, order vs. disorder etc. We have employed seven complexity variables, all derived from LR data, to show that Viking LR active responses can be distinguished from controls via cluster analysis and other multivariate techniques. Furthermore, Martian LR active response data cluster with known biological time series while the control data cluster with purely physical measures. We conclude that the complexity pattern seen in active experiments strongly suggests biology while the different pattern in the control responses is more likely to be non-biological. Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly. This suggests a robust biological response. These analyses support the interpretation that the Viking LR experiment did detect extant microbial life on Mars.


Obviously it isn't generally accepted that this was the proper conclusion. Also, NASA is pushing for sample return, and the point of sample return is that it allows far more detailed examination in a laboratory than could be done by robots on Mars.

Yes, the proper conclusion isn’t generally accepted (that’s most often how science works!) but the sentiment is no doubt gaining momentum. And while sample-return is a fine idea I’d think it too costly and time consuming, given the engineering, technical, sterilization or other issues involved. I suppose it’ll be less than a one way manned mission so at least it’s the next best thing. Personally, I think we’ve discovered life on Mars and could confirm or disprove this conclusion with lander investigations.

R.A.F.
2013-Dec-20, 07:04 PM
...while sample-return is a fine idea Id think it too costly and time consuming, given the engineering, technical, sterilization or other issues involved. I suppose itll be less than a one way manned mission so at least its the next best thing.

You "suppose" that a robotic sample return mission would be less "costly" than a manned "suicide" mission??


Really??

Selfsim
2013-Dec-20, 10:00 PM
The Viking's LR experiment was so well designed that they have envisioned that possibility.To be sure that no geo-chemical reaction was responsible for a positive result a second soil sample (control test) coming from the same spot was heated at 160 degree celsius destined to kill the living microrganisms but this was not hot enough to destroy any eventual chemicals.All control test(s) were negative thus demonstrating that the positive results obtained were not caused by a geo-chemical reaction.So, the 160 C was justified, (by Levin etal), on the basis of killing an assumed microorganism population .. and not selected on the basis of accounting for the now known to be, significantly more complex martian soil chemistry?

Did Levin etal consider adsorbed CO2 on smectite and palagonite surface materials, and/or reactions with co-evolving HCl before concluding that the 160C had killed the ideologically assumed micro-organisms?:
Another possible CO2 source, given the inferred presence of akaganeite and substantial proportions of perchlorate or chlorate phases in the samples, is that HCl evolved at lower temperatures, and then reacted with carbonate minerals. The onset of evolved HCl is nearly simultaneous with CO2 releases in JK and CB (Figs. 1 & 2), suggesting that low-temperature acid dissolution and subsequent thermal decomposition of carbonates may be responsible for some of the evolved CO2 (Fig. S2). Total CO2 evolved is equivalent to <1 wt. % carbonate and, if present, carbonates are at abundance below the detection limit by CheMin. Adsorbed CO2 is an unlikely candidate for the CO2 peak near 300 C because the majority of adsorbed CO2 is expected to be desorbed from smectite and palagonite-like material surfaces at temperatures <200 C. The low-temperature shoulder around 100-200 C in JK materials could reflect adsorbed CO2, although it was not seen in CB materials.So the 160C might have been sufficient to release surface adsorbed CO2 and/or stimulate extant carbonate reactions with HCl (which is formed when soil H2O and perchlorates come together during heating up to 160C). Ie: The CO2 and perchlorate derived HCl, was 'boiled off' at the lower 160C temperature, and when the subsequent LR test was then conducted on the same sample, the primary CO2 reaction normally being measured by the LR detection process, (on the non-heat treated samples), was already complete, hence no evolved C isotope was subsequently detected on the control(?)

The non-control samples still had to go through these reaction steps, with slower evolution of isotope marked CO2, due to the lower temperatures (than the control) at which they were conducted. Whenever nutrient was added to the samples, the H2O solvent in the nutrient mixture reactivated the process ... resulting in subsequent stimulated CO2 emissions?

There still exists the possibility of organic contaminants in the Viking sample test chambers reacting with products produced during the various stages of the LR tests, too.

The LR tests were not fully capable of eliminating geo-chemical explanations, now known to be likely, courtesy of Phoenix's, and now SAM's, more generic lab tests (Which were not not specifically obsessed with finding something which may not actually exist in the samples … ie: microbial life).


Effectively that would be greath if NASA release some information from the High Definition Cam and the Chem Cam about these green patches on rocks observed by Curiosity low resolution MastCam and from SAM liquid extraction method used on soil samples.
As i have pointed out earlier Levin as filed a FOIA request to force NASA to release that information.
http://www.gillevin.com/Mars/FOIA_TO_NASA_HEADQUARTERS.pdfThe seeming 'green' patches have already been described, (somewhere else), as being attributable to geochemical minerals … (no-one except Levin, seems to reject this quite rational explanation) .. and at least one ChemCam spectrum has already been released (it was in the PhysOrg article about the 100,000 firings being surpassed).

PS: Levin's request dated Dec 9, 2013 assumes the wet chemistry process has been attempted. I read somewhere (maybe a Ken Kremer UTI interview?) that Mahaffy etal have said that no wet chemistry runs have yet been conducted(?). Also, ChemCam raw images are on the JPL site (http://mars.jpl.nasa.gov/msl/multimedia/raw/), up to and including Sol 488, (they about as boring as dried toast!) What's the issue here?

MaDeR
2013-Dec-21, 05:15 PM
Sorry for late answer.


Dissimilar evolutionary micro-environments correlated with the respective Earth-microbe domains didn't alter the core basis of their common genetic model elements, nor the core basis of a common metabolism.
Your claim here is deliberately vague, making it almost worthless.

By the way, this kind of claim flies in face of your other claim that life is so uttely unpredictable. If it is unpredictable, you cannot assert that it surely must have same "genetic model elements" and "core basis of common metabolism".

And it has nothing to do with distinguishing native life from transplanted life anyway, as we can readily distinguish and know history of life from different enviroments despite it having common ancestor (thus same "genetic model elements" and "core basis of common metabolism"). Martian life - both "native" and "transplanted here" cases - would be relatively easy to distinguish, even if native life would have for some reason same "genetic model elements" and "core basis of common metabolism".


IMO, hope for finding a separate lineage then, is misguided, costly and time consuming.
Knowing answer to question "Was discovered life native or was it transplanted?" is very important. I can't view your opinion as anything other than excercise in denial - fearing discovery that you would not like. This is stance of ideologue, not scientist.

Selfsim
2013-Dec-22, 08:35 AM
So, I know this is a bit off topic, so I'll keep it short & sweet, but I'd just like to thank an old adversary with whom I have spent quite a few productive posts, wrangling about the Levin LR Viking tests. (I'm referring to "Serious Matters" aka "DonJ"). If you're out there DonJ, I hope you get to read this (& I hope its not against 'the rules' to pay some respects). Thanks for the time you spent wrangling with me on this .. its appreciated.

I hope Curiosity gets to the bottom of it .. (yeah, I know .. dig ... deep, eh?).

Cheers, good luck & see ya round the net ..
PS: If you're left wondering .. I had no part in what happened to Serious Matters, although I was pretty sure about who it was, I was dealing with :) .