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Ross 54
2014-Feb-25, 09:08 PM
It appears much likelier than before that fossils have been found in a meteorite from Mars. A paper on apparent fossils in the Yamato 000593 meteorite, recovered from Antarctica, has been vetted for nearly three years, and just published. The paper details how tubular and spherical structures were found on the microscopic scale. It also explains why these are not likely to be due solely to geological or mineralogical processes. It appears that if such structures were found in ordinary Earth rocks, they would be classified as fossils, with little ado. See a link to the paper, below:
http://online.liebertpub.com/doi/full/10.1089/ast.2011.0733

Colin Robinson
2014-Feb-26, 09:25 AM
It appears much likelier than before that fossils have been found in a meteorite from Mars. A paper on apparent fossils in the Yamato 000593 meteorite, recovered from Antarctica, has been vetted for nearly three years, and just published. The paper details how tubular and spherical structures were found on the microscopic scale. It also explains why these are not likely to be due solely to geological or mineralogical processes. It appears that if such structures were found in ordinary Earth rocks, they would be classified as fossils, with little ado. See a link to the paper, below:
http://online.liebertpub.com/doi/full/10.1089/ast.2011.0733

Thank you for the link. Looks like the argument is strengthening that Mars once had life, whether or not it still does...

Selfsim
2014-Feb-26, 10:21 AM
Thank you for the link. Looks like the argument is strengthening that Mars once had life, whether or not it still does...How could you possibly conclude that ... from this?:

We cannot exclude the possibility that the carbon-rich regions in both sets of features may be the product of abiotic mechanismsThen , from the ALH84001 Wiki entry (http://en.wikipedia.org/wiki/ALH84001#Hypothetical_biogenic_features) ..

In November 2009, a team of scientists at Johnson Space Center, including David McKay, argued that since their original paper was published, the biogenic hypothesis has been "further strengthened by the presence of abundant fossil-like structures in other Martian meteorites."However, the scientific consensus is that "morphology alone cannot be used unambiguously as a tool for primitive life detection."Interpretation of morphology is notoriously subjective, and its use alone has led to numerous errors of interpretation.

... however, textural and compositional similarities to features in terrestrial samples, which have been interpreted as biogenic, imply the intriguing possibility that the martian features were formed by biotic activity.There is no 'implication' other than by means of invoking overactive imaginations, which are used to seeing patterns from an already known life abundant planet.

How can an argument be 'strengthened' by a clearly ambiguous result?

Paul Wally
2014-Feb-26, 10:30 AM
I think, what one has to look for in these images is repetition of complex structures. Repetition could be an indication of replication.

Noclevername
2014-Feb-26, 11:56 AM
New and better evidence

No, a new interpretation of old data.

As far as I'm concerned, a meteorite that's been on Earth for millions of years has had plenty of time to be contaminated. Unless we find unambiguous evidence on Mars of living things, it's still undecided to me.

marsbug
2014-Feb-26, 04:05 PM
The paper itself is only claiming that the carbon globules imply that its possible Mars once had life. the Water related discoveries from the Mars rovers also imply it's possible Mars once had life. As do a lot of data.

It's entirely within the realms of the possible that Mars once had life. It just hasn't been proved. This paper isn't proving it, isn't claiming to, and is actually a great example of the kind of interesting but no-new-news-here papers that academics will publish when they've got a bunch of data that doesn't tell them anything very new. But it's entirely possible to slap a cool title on the top, get it published because it's still solid enough science, get a slightly sensationalised news article about it written, and when it comes to getting funding the funding panel might just decide not to read the meat of all fifty cool sounding papers you've got to show them, fork over the cash, and go for lunch.

Because they're working for pay, and they'll get their pay anyway. Grrrrrrr.

Ross 54
2014-Feb-26, 04:14 PM
The contents of the paper make it clear that there was original research here, not merely reinterpretation of work done before. More than life-like morphologies are involved. The tunnels and spheres are preferentially enriched in carbon, as might be expected if they are the remains of once-living things. The moderately undulating course of the many tunnels, and their generally parallel trend had already be described as characteristic of erosion paths of microorganisms.
Similar structures have been discerned in the famous Nakhla meteorite, despite the fact that it has had a very much shorter stay on Earth. This would seem to argue against terrestrial contamination.
The researchers next propose to analyze the carbon enriched areas of the meteorite. They would presumably be interested in the isotope ratios. A sufficient predominance of the lighter isotopes would support the fossil hypothesis. It has been known for some time that living things make more use of lighter carbon isotopes than heavier ones.
It has been stated that life, past or present, on Mars has not been proved. This is of course correct. Apart from mathematics, I wasn't aware that science dealt in 'proofs'. A given scientific description or interpretation of what is observed may be widely considered the most probable one, but this is always subject to revision, in the face of new data. Has the probability of Mars once harboring life just increased? It appears that this may be the case.

R.A.F.
2014-Feb-26, 04:45 PM
Has the probability of Mars once harboring life just increased? It appears that this may be the case.

I doubt that....I'm with Noclevername on this...we're really not going to know the answer to the life question until we go there.

Selfsim
2014-Feb-26, 08:44 PM
... More than life-like morphologies are involved. The tunnels and spheres are preferentially enriched in carbon, as might be expected if they are the remains of once-living things…The study reports on the findings of tests generated by this hypothesis (ie: detailed inspection of the meteorite). The results cited by the authors were inconclusive and ambiguous, and yet you still state:
… Has the probability of Mars once harboring life just increased? It appears that this may be the case.Which is not a logical conclusion based on the conclusion which could not discriminate between known abiotic and biotic processes. In fact abiotic processes could not be eliminated even when the specimen structures were viewed from the hypothetical viewpoint of morphology.

But all this was also already well known and documented before the study commenced.

Your conclusion is non-sequitur.


… A given scientific description or interpretation of what is observed may be widely considered the most probable one, but this is always subject to revision, in the face of new data.Huh? Descriptions of the remnants of past processes don't include causes. Those descriptions also don't include 'probable ones' either … which is why proper descriptions themselves, are not subject to revision. Data is never revised.

Selfsim
2014-Feb-26, 09:07 PM
...we're really not going to know the answer to the life question until we go there.Also noteworthy, is that even analysis done on Earth, with the full arsenal of instrumentation which can be brought to bear on the problem, can still drag on for years when it comes to questions concerning the presence or absence of just Earth-life.

The belief in the existence of exo-life is so entrenched that I even doubt 'no life' could be accepted, even with evidence which could be gathered by say, a permanent 'Mars One' type of encampment on Mars(??)

marsbug
2014-Feb-26, 09:46 PM
The contents of the paper make it clear that there was original research here, not merely reinterpretation of work done before. More than life-like morphologies are involved. The tunnels and spheres are preferentially enriched in carbon, as might be expected if they are the remains of once-living things. The moderately undulating course of the many tunnels, and their generally parallel trend had already be described as characteristic of erosion paths of microorganisms.
Similar structures have been discerned in the famous Nakhla meteorite, despite the fact that it has had a very much shorter stay on Earth. This would seem to argue against terrestrial contamination.

Yes. And? It' true this original research, but it's found more of what has previously been found in other Martian meteorites. The tunnels that resemble microbial erosion patterns? They've been known for ten years at least. Edit: I can't find the paper - it was a long while ago. I'll keep looking. I remember being at Uni and thinking how intriguing it was. The paper is interesting, it makes it seem more plausible that the features described are indigenous (from mars not post landing artefacts), but I don't see how it makes it much plausible that they are biological in origin. It's still totally within the realms of possibility they are, but while this paper makes existing conclusions seem more solid, it isn't adding much of its own. It's worth reading, and worth knowing what's been found, but while there is new evidence here I don't agree that its 'better' evidence.


It has been stated that life, past or present, on Mars has not been proved. This is of course correct. Apart from mathematics, I wasn't aware that science dealt in 'proofs'. A given scientific description or interpretation of what is observed may be widely considered the most probable one, but this is always subject to revision, in the face of new data. Has the probability of Mars once harboring life just increased? It appears that this may be the case.

I have to disagree, for the reasons given above. After reading the paper I'm slightly more convinced the features are formed on Mars, but it seems no more likely they were formed by biology than before.

I don't want to seem ungrateful by knocking your thread title, I'm very grateful to you for sharing this. And I can respect that you're opinion on how convincing the data is of past biology is higher than mine. And that's a legitimate difference, as I can see that the evidence does at least leave the door as open as before on the possibility of these structures being biologically formed.


The researchers next propose to analyze the carbon enriched areas of the meteorite.

I'll wait for that one, and look on this as their prelude. I'm a huge fan of David Vs Goliath, especially in space exploration. I'd love to see something found in one of these meteorites that was be much more likely to be formed by biology than not. But this isn't it IMHO.

Ross 54
2014-Feb-27, 05:18 PM
Possible bacterial erosion tunnels previously noted in Mars meteorites? Looking over past accounts, I find that this is the case. Thank you for bringing this fact to my attention.
Another point about the structures in the Yamato meteorite may be new, and more telling. The spheroidal objects, suspected of being microbes, appear to be about 300 nanometers in diameter. This is within the size range of known bacteria.
It was reported that the objects in the Allan Hills meteorite suspected of being fossils were only about 20 to 100 nanometers across. It was objected that this was too small, rendering a chemical, rather than a biological explanation the more likely. If that objection has been removed in the current instance, it may amount to better evidence for once-living organisms on the planet Mars.

marsbug
2014-Feb-27, 05:31 PM
The size of the ALH structures was a severe mark against them being fossils, and you are correct that the new findings are on structures within the bacterial size range. So, yes, I have to concede that that is more suggestive of a biological origin than the ALH structures were. It's still a long, long, road from there to showing that these structures are more likely biological than not. But the size range being within the realm of known cells makes it seem a bit more plausible that they could be microfossils.

I still don't find these findings that spectacular, and I'm waiting for the analysis of the carbon. But the data is new, and it makes it look more likely the structures were formed on Mars, and makes it slightly more likely they had a biological origin, as they are in the size range for known cells.

Selfsim
2014-Feb-27, 08:37 PM
... But the size range being within the realm of known cells makes it seem a bit more plausible that they could be microfossils.
...
and makes it slightly more likely they had a biological origin, as they are in the size range for known cells.So of all the things known which fit into 'the size range', what percentage of them have biotic causes?

After all, consideration of this aspect, is the only way this interpretation could gain any 'weight', no?

Selfsim
2014-Feb-27, 10:18 PM
Possible bacterial erosion tunnels previously noted in Mars meteorites? Looking over past accounts, I find that this is the case. Thank you for bringing this fact to my attention.How does 'a possible bacterial erosion tunnel previously noted in Mars meteorites', suddenly become a 'fact'?


Another point about the structures in the Yamato meteorite may be new, and more telling. The spheroidal objects, suspected of being microbes, appear to be about 300 nanometers in diameter. This is within the size range of known bacteria.
It was reported that the objects in the Allan Hills meteorite suspected of being fossils were only about 20 to 100 nanometers across. It was objected that this was too small, rendering a chemical, rather than a biological explanation the more likely. If that objection has been removed in the current instance, it may amount to better evidence for once-living organisms on the planet Mars.Or more likely, the observation of smaller spheroids implies that ALH84001's structures simply represented a sampling bias in the population of known meteorites? .. Whilst the sizes of the spheroids in the ALH and Yamato samples may be an order of magnitude different, there is no reason to rule out that larger ones start out from smaller ones and therefore a distribution of varying sizes would be expected, no?

In either case, Mars is known to have large numbers of spheroidal surface objects, (ie: hematite 'blueberries' (formed by aqueous alteration, ie: mineral precipitation), and the concentrically structured 'newberries', which present as being consistent with formation by precipitation). Spherules are also known to be produced by meteoroid impacts on the Moon. There's nothing unusual about seeing spheroidal structures in geologically formed structures where there is no other evidence of life, no matter where they're from.

In terms of composition, kerogen-like material was claimed to have been found in ALH84001. It has also been detected in interstellar clouds and dust around stars, so does the ALH claim carry any more 'weight' in terms of possible biogenic origins? (I don't see how). Even if the Yamato spheroids contain similar kerogen, I don't see this meaning any 'more', in terms of biogenetic origins, than the ALH claim does.

marsbug
2014-Feb-28, 12:10 PM
Well, on the size issue, perhaps I miss something. But if the structures are orders of magnitude smaller than any known living organism there is no chance of them being the fossil of a living organism, unless we start speculating about a previously unknown type of life just so we can say we've found aliens (as happened with the original ALH findings). If a group of structures is in the size range of living organisms then they are no longer ruled out being microfossils on the basis of size. So it's fair to say that being fossilised microbes is more plausible for the bigger than it is the orders of magnitude smaller structures. Yes there are a zillion other explanations - being in the right size range doesn't make for a strong case for biogenic origin, nor IMHO does the rest of the paper. It just makes a slightly stronger case than the original ALH findings.

iquestor
2014-Feb-28, 01:38 PM
But if the structures are orders of magnitude smaller than any known living organism there is no chance of them being the fossil of a living organism, unless we start speculating about a previously unknown type of life just so we can say ....

I disagree. Just because the structures are smaller than "known" Earth organisms does not mean there is "no chance" they are Martian fossils. It means that we haven't encountered organisms or their fossils that small, and leads us to find other ways to determine if the structures are biological or not.

edit: I would also add that ANY type of life found outside of Earth's biosphere is "previously unknown life"...

Eadfrith
2014-Feb-28, 03:45 PM
No, a new interpretation of old data.

As far as I'm concerned, a meteorite that's been on Earth for millions of years has had plenty of time to be contaminated. Unless we find unambiguous evidence on Mars of living things, it's still undecided to me.
All of that has been ruled out.

Anyway check out what I posted on Tumblr
http://eosterwine.tumblr.com/post/78111326687/recent-image-from-the-curiosity-rover-clearly

http://mars.jpl.nasa.gov/msl/multimedia/raw/?rawid=0551MR2233051000E1_DXXX&s=551

Ross 54
2014-Feb-28, 06:10 PM
Efforts were made to rule out contamination. Yamato 000593 was compared to the Nakhla meteorite, which was quickly recovered after it landed. Both had similar tunnels resembling bacterial erosion tunnels in ordinary Earth rocks. If this were Earthly contamination it seems unlikely that the interior of the latter would be similarly affected.
Besides this, a control meteorite (LEW 87051) found in Antarctica, and exposed to the same conditions there, but not originating on Mars, was examined. It did not exhibit the undulating, yet generally parallel tunnels.

marsbug
2014-Feb-28, 06:31 PM
I disagree. Just because the structures are smaller than "known" Earth organisms does not mean there is "no chance" they are Martian fossils. It means that we haven't encountered organisms or their fossils that small, and leads us to find other ways to determine if the structures are biological or not.

edit: I would also add that ANY type of life found outside of Earth's biosphere is "previously unknown life"...

OK, I'm wrong to couch what I say in absolutes like 'no chance'. But, that said...We're not talking dinosaur bones, or even preserved chemistry of an unarguably biotic type here. We'd be talking about identifying an entirely new kind of life, that we have nothing comparable to on record, based on the shape and composition of some microscopic carbon formations being arguably a bit life like. At least the new paper has looked at structures that, IF they are fossils, would originate from an organism that we might have valid terrestrial comparisons for. The more plausible variants of panspermia leave the door open on any Martian life being relate to Earth life, so a meaningful comparison to terrestrial microfossils might be possible.

And, no, as I read the paper the authors do not claim that contamination is ruled out, they have just done their best to minimise the possibility. And they have gone to great length, and the possibility of contamination seems as minimal as they could reasonably make it. Nor are they claiming detection of micro fossils, they are claiming there is nothing in their findings that rules out these structures being micro fossils, that it is still on the list of possible ways these structures could have originated, and that they ave enough data to justify further investigation. None of which is justification for either damning these investigators as tin foil hat wearing cranks, or claiming 'we now KNOW we are not alone!!!' as some folk are inevitably gong to do.

iquestor
2014-Feb-28, 08:35 PM
OK, I'm wrong to couch what I say in absolutes like 'no chance'. But, that said...We're not talking dinosaur bones, or even preserved chemistry of an unarguably biotic type here. We'd be talking about identifying an entirely new kind of life, that we have nothing comparable to on record, based on the shape and composition of some microscopic carbon formations being arguably a bit life like. At least the new paper has looked at structures that, IF they are fossils, would originate from an organism that we might have valid terrestrial comparisons for. The more plausible variants of panspermia leave the door open on any Martian life being relate to Earth life, so a meaningful comparison to terrestrial microfossils might be possible.

And, no, as I read the paper the authors do not claim that contamination is ruled out, they have just done their best to minimise the possibility. And they have gone to great length, and the possibility of contamination seems as minimal as they could reasonably make it. Nor are they claiming detection of micro fossils, they are claiming there is nothing in their findings that rules out these structures being micro fossils, that it is still on the list of possible ways these structures could have originated, and that they ave enough data to justify further investigation. None of which is justification for either damning these investigators as tin foil hat wearing cranks, or claiming 'we now KNOW we are not alone!!!' as some folk are inevitably gong to do.

Since we are investigating a meteorite from another planet, and taking great pains to eliminate earth contamination, then of course we are talking about looking for a "new Kind Of Life" if the structures are biological in origin. Any life outside of Earths biosphere is "new" to us since it didn't originate here.

Unfortunately, I don't think we can "prove" these tiny structures are biological, but can only build evidence for one case or the other as we find it. and that's too bad. But I think we have to Go To Mars to figure out if Life is, or was there. Unless we get a meteorite with undeniable macrofossils...

marsbug
2014-Feb-28, 09:07 PM
Since we are investigating a meteorite from another planet, and taking great pains to eliminate earth contamination, then of course we are talking about looking for a "new Kind Of Life" if the structures are biological in origin. Any life outside of Earths biosphere is "new" to us since it didn't originate here....

I agree that all we can do is build the 'for' and 'against' cases, and on any given day see here the balance of probability lies.
I'm not as sold on any life we might find in an Martian meteorite being definitely unrelated to terrestrial life. My understanding of current research into Mars to Earth and Earth to Mars lithopanspemia is that it could conceivably have happened in the deep past (I'm not asserting that it has, just that what I've read leads me to believe the odds of it occurring are large enough to be meaningful). I'll not turn this into the nth panspermia debate, but for me personally, even if one day the balance of evidence was hugely in favour of indigenous microfossils, I wouldn't be totally convinced we had evidence of a true second origin of life until Earth-Mars lithospanpermia had been shown totally improbable.

Edit: BTW regarding the size rag for the spherical structures, the paper describes the carbon structures observed between the iddingsite layers as:


...close-packed spheroidal structures encased within and surrounded by multiple layers of iddingsite-like compositions, ranged in diameter from 100 to 500 nm and are enriched in carbon relative to the underlying host mineral phases and surrounding iddingsite...

Selfsim
2014-Feb-28, 09:50 PM
I agree that all we can do is build the 'for' and 'against' cases, and on any given day see here the balance of probability lies. The point here is that any 'balance of probability' judgements can only be made based on data sourced from past cases of confirmed life. The fact is that past cases of confirmed life only come from the superset of Earth-life. Therefore the basis of 'balance of probability' judgement, is totally and completely biased.

In fact, the 'balance of probability' is nothing more than a place-holder for supporting only a faith-based belief that all life will be recognisable on the same basis Earth-life is recognised which is an hypothesis under test. An hypothesis under test has no place in the interpretation of empirically sourced data, since it is this which is under test in the first place!

This is the whole problem in a nutshell, with any conclusions based on 'a possible bacterial erosion tunnel'. Such conclusions are based on circularity and must be considered to be fallacious. No weight can be assigned to a fallacious argument. The report findings are thus meaningless.

marsbug
2014-Feb-28, 10:24 PM
I don't disagree - if any Martian life is indeed a second origin. But I feel like I should point out that our very definition of life is based on observations solely of Earth life. Plus, as I noted, its within the realms of possible that Mars has been contaminated with Earth life when it was habitable in the deep past.

What other standard could we possibly use that doesn't ultimately root in Earth based life? If we have no other recourse then I'm not sure that your (probably correct) logic has actually gotten us anywhere. Equally, how do we know alien life won't be earthlike at a cellular level? We don't know how many ways 'life' can manifest. And, if there is a possibility that Mars is a distant subset of Earth life, why shouldn't we try to apply Earth life standards?
This is a big field for discussion all of it's own Perhaps it needs its own thread so it doesn't derail this one?

Selfsim
2014-Feb-28, 11:47 PM
I don't disagree - if any Martian life is indeed a second origin. But I feel like I should point out that our very definition of life is based on observations solely of Earth life. Plus, as I noted, its within the realms of possible that Mars has been contaminated with Earth life when it was habitable in the deep past.Sure .. (I agree).
What other standard could we possibly use that doesn't ultimately root in Earth based life? If we have no other recourse then I'm not sure that your (probably correct) logic has actually gotten us anywhere.Try on: there is nowhere to 'go' in the first place!

In order to see 'progress', there must be a target to measure it against. The target is simply to observe what hasn't been observed before. Judgements of 'no progress' only happen, in this instance, when one returns with a null result for a test derived from an hypothesis which includes the return of a result which yields no useful knowledge. If I set such a target in my exploration strategy, I set out with a goal which encompasses a failure to capture what there is to observe.

Speculation and hypothesis about Mars life, to date, has returned no useful knowledge either way about exo-life. If anyone disagrees, then by all means please articulate just exactly what new knowledge about it has it provided(?) .. A report which recognises familiar patterns? I can do similar by imagining faces in cloud patterns!


Equally, how do we know alien life won't be earthlike at a cellular level? I'll be blunt .. 'alien life' only exists in the mind, and nowhere else, until empirically sourced data rules out false positives. This study, yet again, returned at best, ambiguity, when measured against the target concerning exo-life ... and by their own disclosure, what's more.

We don't know how many ways 'life' can manifest. And, if there is a possibility that Mars lf is a distant subset of Earth life, why shouldn't the apply Earth life standards? This is a big field for discussion all of it's own Perhaps it needs its own thread so it doesn't derail this one?There is no 'derailment' if the OP report alludes to 'a possible bacterial erosion tunnel' in the Yamato meteorite.

Colin Robinson
2014-Mar-01, 12:10 AM
A report which recognises familiar patterns? I can do similar by imagining faces in cloud patterns!

Comparing microstructures in Mars rocks with microstructures in Earth rocks is like comparing clouds with faces? Do you really think so?

marsbug
2014-Mar-01, 12:32 AM
What Colin said.

Selfsim
2014-Mar-01, 01:08 AM
Comparing microstructures in Mars rocks with microstructures in Earth rocks is like comparing clouds with faces? Do you really think so?More to the point in question just what, exactly, realises a relationship between 'possible bacterial erosion tunnels' and 'microstructures in Mars rocks'?

Colin Robinson
2014-Mar-01, 03:24 AM
More to the point in question just what, exactly, realises a relationship between 'possible bacterial erosion tunnels' and 'microstructures in Mars rocks'?

Features of the Martian meteorite mentioned in the paper by Lauren White et al, which according to its authors imply the possibility that they were formed by biota...

* carbonaceous material not accompanied by calcium or magnesium.
* spherules similar in shape and size to known forms of microbial life.
* uniform tunnel size and shape within a single sample.
* uniform tunnel diameter along the length of the individual tunnel.
* replacement of the host mineral with hydrous minerals.

Selfsim
2014-Mar-01, 04:40 AM
Features of the Martian meteorite mentioned in the paper by Lauren White et al, which according to its authors imply the possibility that they were formed by biota...

* carbonaceous material not accompanied by calcium or magnesium.
* spherules similar in shape and size to known forms of microbial life.
* uniform tunnel size and shape within a single sample.
* uniform tunnel diameter along the length of the individual tunnel.
* replacement of the host mineral with hydrous minerals.
We cannot exclude the possibility that the carbon-rich regions in both sets of features may be the product of abiotic mechanisms; however, textural and compositional similarities to features in terrestrial samples, which have been interpreted as biogenic, imply the intriguing possibility that the martian features were formed by biotic activity.Re: underlined emboldened text: In other words the textural and compositional similarity relies on terrestrial references for the match, the interpretation and the implication.

Nonetheless, they cannot rule out abiogenic causes also known to occur in terrestrial environments.

Kerogen-like ('organic' carbon based) material has been detected in other meteorites, interstellar clouds and dust around stars. Are we to assume bacteria is also 'at cause' in these cases?
... But wait! ... There's more!:
The presence and distribution of carbon-rich areas with tunnel erosion patterns in iddingsite imply this matter is relatively insoluble, consistent with the geopolymer kerogen (Kim et al., 2006).... no mention of bacterial causes in any of that!

I see no distinguishing difference between a terrestrial bacterial causal interpretation, and my visions of faces in clouds ... Do you?

Colin Robinson
2014-Mar-01, 05:32 AM
Re: underlined emboldened text: In other words the textural and compositional similarity relies on terrestrial references for the match, the interpretation and the implication.

Yes, they are comparing micro-structural and compositional features of rocks from Mars and from Earth.


Nonetheless, they cannot rule out abiogenic causes

Nonetheless, they have given reasons for considering the possibility that biota are the cause.


Kerogen-like ('organic' carbon based) material has been detected in other meteorites, interstellar clouds and dust around stars. Are we to assume bacteria is also 'at cause' in these cases?

No.

What White et al say about the meteorite isn't based only on the presence of carbonaceous material, it is based on the combination of features including carbonaceous material, a water-related mineral (iddingsite) and the morphology of tunnels and spherules.


... But wait! ... There's more!:... no mention of bacterial causes in any of that!

You quoted one sentence from the paper, and the one thing you find significant about that sentence is that it doesn't mention bacteria???


I see no distinguishing difference between a terrestrial bacterial causal interpretation,

I don't think the possibility raised in this paper, "the intriguing possibility that the martian features were formed by biotic activity" is well-described by your phrase "terrestrial bacterial causal interpretation".


and my visions of faces in clouds ... Do you?

Do I see a difference between

* a team of scientists identifying similar compositional and morphological features of rocks from Mars and from Earth, and suggesting that the similar set of phenomena may result from a similar cause

* someone looking at a cloud and thinking it looks like a face ?

Yes, Selfsim, I do see a difference.

Selfsim
2014-Mar-01, 06:35 AM
What White et al say about the meteorite isn't based only on the presence of carbonaceous material, it is based on the combination of features including carbonaceous material, a water-related mineral (iddingsite) and the morphology of tunnels and spherules.Which is no different from the ALH84001 debacle. From which mainstream science has concluded (I quote for the second time in this thread):

Then from the ALH84001 Wiki entry (http://en.wikipedia.org/wiki/ALH84001#Hypothetical_biogenic_features) ..
In November 2009, a team of scientists at Johnson Space Center, including David McKay, argued that since their original paper was published, the biogenic hypothesis has been "further strengthened by the presence of abundant fossil-like structures in other Martian meteorites."However, the scientific consensus is that "morphology alone cannot be used unambiguously as a tool for primitive life detection."Interpretation of morphology is notoriously subjective, and its use alone has led to numerous errors of interpretation.So, we have yet another ambiguous finding (as I have maintained all along in this thread).
You quoted one sentence from the paper, and the one thing you find significant about that sentence is that it doesn't mention bacteria???
...
I don't think the possibility raised in this paper, "the intriguing possibility that the martian features were formed by biotic activity" is well-described by your phrase "terrestrial bacterial causal interpretation".It wasn't my phrase. Someone else added that into this thread, you'll find. (It certainly wasn't White etal, either).


Do I see a difference between

* a team of scientists identifying similar compositional and morphological features of rocks from Mars and from Earth, and suggesting that the similar set of phenomena may result from a similar cause

* someone looking at a cloud and thinking it looks like a face ?

Yes, Selfsim, I do see a difference.Well, that's Ok ... and I don't .. for these reasons:
Of the various tests used, three have been shown to be particularly useful: (1) the mm-scale morphology of the objects in question; (2) the carbon isotopic composition of organic matter associated with and/or comprising the fossil-like structures; and (3) the chemical (molecular) makeup of the fossil-like objects. In principle, therefore, the question of biogenicity can be easily answered. But in practice, the answer has proven elusive, primarily because of a lack of analytical techniques having sufficient power to provide the high resolution three-dimensional morphological information needed to definitively address the question, and an absence of means by which to directly link, in individual microscopic specimens, morphological information to elemental-isotopic and structural-molecular compositions.*
* Morphological behavior of inorganic precipitation systems - Instruments, Methods, and Missions for Astrobiology II" (http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=995013). Garcia-Ruiz, SPIE Proceedings. Proc. SPIE 3755. December 30, 1999. doi (http://en.wikipedia.org/wiki/Digital_object_identifier):10.1117/12.375088 (http://dx.doi.org/10.1117%2F12.375088).

Colin Robinson
2014-Mar-01, 07:45 AM
Which is no different from the ALH84001 debacle. From which mainstream science has concluded (I quote for the second time in this thread):
So, we have yet another ambiguous finding (as I have maintained all along in this thread).

You seem to think that unless the evidence is conclusive, there is no more substance to it than faces in clouds. You seem to think that if we don't have proof beyond reasonable doubt, then we haven't got a clue.

What White et al say in their conclusion is neither that they have proof beyond reasonable doubt nor that they haven't got a clue. They say that past martian biotic activity in this rock is an "intriguing possibility" consistent with the morphological and compositional data which they found.

The WP statement you've quoted (based on Garcia-Ruiz) mentions the difficulty of linking morphological and compositional data in individual microscopic specimens. What this says to me is that this field needs more research with improved techniques.

In short, there is more to be done. Which is what the paper by White et al actually proposes also.

Selfsim
2014-Mar-01, 08:11 AM
You seem to think that unless the evidence is conclusive, there is no more substance to it than faces in clouds. You seem to think that if we don't have proof beyond reasonable doubt, then we haven't got a clue.Are your perceptions now also going to become fact as well?


What White et al say in their conclusion is neither that they have proof beyond reasonable doubt nor that they haven't got a clue. They say that past martian biotic activity in this rock is an "intriguing possibility" consistent with the morphological and compositional data which they found.Which is nothing more than opinion ...


The WP statement you've quoted (based on Garcia-Ruiz) mentions the difficulty of linking morphological and compositional data in individual microscopic specimens. What this says to me is that this field needs more research with improved techniques. In short, there is more to be done. Which is what the paper by White et al actually proposes also.Anyone could have said that regardless of any martian biotic activity ideas.
Actually the entire study would have represented the same value, had the entire martian biotic activity idea been completely deleted.

Noclevername
2014-Mar-01, 08:35 AM
Are your perceptions now also going to become fact as well?

I read and re-read what Colin wrote, and I still don't understand how you jumped to that conclusion that his opinion would "become fact". He was talking about your oft-repeated statements.


Now, as to the content of your breezy dismissal; Not all perceptions have equal weight, or are equally useless. A hypothesis consistent with observation is not a "fact", but it is of more scientific value to consider than an opinion that is inconsistent with observation. Science is as much about ruling things out as it is about proving things. This observation does not rule out Martian bacteria. That's not support for the idea of Martian life, just means the possibility is still open. Which is what I've seen other posters say since the beginning of this thread.


Which is nothing more than opinion ...

See above.



Anyone could have said that regardless of any martian biotic activity ideas.
Actually the entire study would have represented the same value, had the entire martian biotic activity idea been completely deleted.

Depends on what you value.

Now, I don't think this particular paper is worth squat, and I don't think it's evidence of Martian life. But that's because I disagree with their methodology. To dismiss it just because it mentions the possibility of ET life is barking up the wrong dog. You appear to be claiming that no one should THINK about the possibility of ET life; Well, that's not going to happen. People will continue to poke at various parts of the Universe and say "Any life here? Is this alive?" It's human nature. We want to know if we're alone. And all the complaining about it on an internet forum will not make it go away.

By all means, please continue to be critical of such examinations, poke holes in their methodology, etc. But do it for the right reasons; because the science is sloppy. Certainly refute anyone who actually draws conclusions based on bad evidence, and I'll join you in doing so... When it actually happens.

But please, don't keep confusing opinions with claims. It's a bad habit.

Selfsim
2014-Mar-01, 10:22 AM
I read and re-read what Colin wrote, and I still don't understand how you jumped to that conclusion that his opinion would "become fact". Well that might be because I didn't jump to any such conclusion!
'Twas a question for Colin .. not a conclusion.
There appears to be a very fine line between perception and reality around these parts.
And yet the difference between the two often turns out to be huge.
He was talking about your oft-repeated statements.Are these statements of relevance to the OP? (I, of course, wouldn't have a clue about this at this point ...)

Now, as to the content of your breezy dismissal; Not all perceptions have equal weight, or are equally useless. What do perceptions have to do with empirical data collection?
A hypothesis consistent with observation is not a "fact", but it is of more scientific value to consider than an opinion that is inconsistent with observation. Science is as much about ruling things out as it is about proving things.And White etal have not ruled out any abiogenic causes. Thus, there is no distinction between abiogenic and biogenic causes evident from the sample examined.
This observation does not rule out Martian bacteria. That's not support for the idea of Martian life, just means the possibility is still open. Which is what I've seen other posters say since the beginning of this thread. What exactly is 'martian bacteria'?
Why should I worry about what posters have said 'since the beginning of this thread', if its all been about something which has been dreamed up?


Now, I don't think this particular paper is worth squat, Well that's your opinion. Mine is the opposite .. for reasons which have nothing to do with 'martian bacteria'.
... and I don't think it's evidence of Martian life. But that's because I disagree with their methodology. To dismiss it just because it mentions the possibility of ET life is barking up the wrong dog. Who has dismissed it for that reason? I haven't.
You appear to be claiming that no one should THINK about the possibility of ET life; Well, that's not going to happen. People will continue to poke at various parts of the Universe and say "Any life here? Is this alive?" It's human nature. We want to know if we're alone. And all the complaining about it on an internet forum will not make it go away.Then it might be a good idea for you to consider stopping 'complaining' about it, I guess(?) ..


But please, don't keep confusing opinions with claims. It's a bad habit.It sure is a bad habit .. and its not one of mine!

Spacedude
2014-Mar-01, 02:25 PM
If it is proven that Mars did (or does) support microbial life I look forward to the debate of whether it originated from the Earth via meteor impact contamination some billions of years ago. Stay tuned...

marsbug
2014-Mar-01, 04:43 PM
If we managed to isolate a Martian microbe I imagine we'd be able to tell by DNA analysis pretty easily if ti was related to earth life, and how closely.

To try and move the debate onto a different track: IF, one day, very solid evidence of Martian life were found from an analysis of this (or any) Martian meteorite, what effect would this have on Mars exploration?

Edit: Also, noclevername, you mentioned you disagreed with the papers methodology? I'd be very interested to read your criticisms of how they proceeded. I've got some understanding of geology and the analysis techniques (like EDS) involved so I'm curious!

Ross 54
2014-Mar-01, 05:41 PM
It of course seems likely that the discovery of even simple life on, or from Mars would spur greater exploration of the red planet. The broader implications are also worth considering.
If one world seeded the other with life, the likeliest scenario appears to be life migrating from Mars to Earth. Many more meteorites can make that trip, as compared to one from Earth to Mars, due to dynamical considerations. if this is what occurred, it would make us the descendants of transplanted Martian life.
If life arose independently on both worlds, this would suggest of a universe densely inhabited with life, thus greatly increasing the chances of other intelligent life arising in the cosmos.
Either possibility is remarkable in its own way.

marsbug
2014-Mar-01, 05:59 PM
You don't think that politicians might go 'Question answered, so you science types don't need to spend money on answering it anymore. And it was answered by looking at a meteorite, so clearly this whole exploring by spaceship thing is overrated'?

OK, I oversimplify and I'm about to play devil advocate. But everyone seems to assume that the discovery of alien life would be a huge boost to exploration. Am I the only one who thinks the discovery of alien life might not be totally positive for exploration budgets, and that in some ways it might result in less political will to send people and robots to mars?

Eadfrith
2014-Mar-01, 06:03 PM
This image I linked to earlier shows proof of fossils in Martian rocks.
http://mars.jpl.nasa.gov/msl-raw-images/msss/00551/mcam/0551MR2233051000E1_DXXX.jpg

marsbug
2014-Mar-01, 06:20 PM
No offence but I think you should take that to the ATM section, since macrofossils on Mars is definitely not an accepted mainstream idea.

Ross 54
2014-Mar-01, 06:58 PM
I suppose there could be a political reaction against exploration. One senator, Mr. Proxmire, managed to arrange and influence matters so that NASA lost its incipient SETI program in 1992. More often, it seems that politicians try to sense a trend in public interest, then get out in front and lead the parade. Given the public interest in ET life in general, this seems more likely to me, and especially if we had solid evidence for life on or from Mars.

marsbug
2014-Mar-01, 07:30 PM
Hopefully that's the way it would play out. On the whole I think there'd be a pretty positive reaction, but I think the case where there's a partly negative reaction should be considered. It's my engineer training: Whenever possible, build to withstand the worst likely scenario!

Noclevername
2014-Mar-01, 11:51 PM
...

:wall::wall::wall:

I tried.