Page 3 of 10 FirstFirst 12345 ... LastLast
Results 61 to 90 of 286

Thread: Mars Soil Resembles Veggie-Garden Dirt, Lander Finds

  1. #61
    Join Date
    Oct 2009
    Posts
    1,360
    Quote Originally Posted by Selfsim View Post
    Don J;

    Feel free to continue campaigning for a second attempt at life detection. (Same for Levin).
    A second attempt at life detection on Mars is inevitable which will give positive results(again) and that will lead to a big dilemma about a collect and return sample mission. The debate will turn around the danger of contamination....then as a perfect timing it will be decided to send a human mission to Mars.
    Quote Originally Posted by Selfsim View Post
    I personally feel very little motivation for repeating experiments which have already returned inconclusive results (regardless of the reasons and explanations for that).
    Datas collected by other probes after Viking missions rather point to Levin's conclusion, for example the detection of methane in the Martian atmosphere.
    http://www.esa.int/Our_Activities/Sp...rs_a_new_clue2
    The measurements confirm so far that the amount of methane is very small – about 10 parts in a thousand million, so its production process is probably small. However, the exciting question remains: “Where does this methane come from?”

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

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

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

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

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


    Quote Originally Posted by Selfsim View Post

    The strategy which motivated the experiments in the first place was fundamentally flawed, (and still persists), so I feel great reticence when it comes to supporting a repeat mission. The idea of detecting something to 'prove' someone's speculative fantasy, seems akin to the hunt for the Holy Grail.
    I don't think that a new mission at life detection on Mars will be guided by fantasy but rather by studying all the datas gathered by all the missions on Mars including Viking life detection results.
    Last edited by Don J; 2013-May-04 at 06:23 AM. Reason: bolding+typo

  2. #62
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by Don J View Post
    A second attempt at life detection on Mars is inevitable which will give positive results(again) and that will lead to a big dilemma about a collect and return sample mission. The debate will turn around the danger of contamination....then as a perfect timing it will be decided to send a human mission to Mars.
    All outlined in the notorious NASA Astrobiology Roadmap. Nothing new here .. its just a plan with only inconclusive data and more stories behind it all.

    Quote Originally Posted by Don J
    Datas collected by other probes after Viking missions rather point to Levin's conclusion, for example the detection of methane in the Martian atmosphere.
    http://www.esa.int/Our_Activities/Sp...rs_a_new_clue2
    Old hat ... the 2004 Mars Express PFS lacks precision, and requires an interpretive model which does not explain all the spectral anomalies in the data. The other two Earth-based measurements had difficulties distinguishing Mars' methane absorption spectra from Earth's. Curiosity has found none so far (why not?).
    Again, inconclusive (at best).

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

  3. #63
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by ASTRO BOY View Post
    The only way to get an answer to the possibility of life to ever have existed is to send test equipment. That will then give us some extra validity one way or the other and possibily support or invalidate other interpretations.
    Sitting on ones hands achieves nothing.
    See, the problem lies in the first part of the first statement: "The only way to get an answer to the possibility of life to ever have existed ..."
    The very wording implies that the search for life is the primary objective. That's what Viking was all about .. and look what we ended up with .. inconclusive results (which no-one can agree on), a bunch of 'faithful' 'hopefuls' unwilling to acknowledge the inconclusive outcomes, and the lead bio-testing design engineer attempting to resurrect his reputation by publishing seemingly endless sequels.

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

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

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

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

  4. #64
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by Selfsim View Post
    See, the problem lies in the first part of the first statement: "The only way to get an answer to the possibility of life to ever have existed ..."
    The very wording implies that the search for life is the primary objective. That's what Viking was all about .. and look what we ended up with .. inconclusive results (which no-one can agree on), a bunch of 'faithful' 'hopefuls' unwilling to acknowledge the inconclusive outcomes, and the lead bio-testing design engineer attempting to resurrect his reputation by publishing seemingly endless sequels.
    I for one would rather put the prospect for progress and discovery with the decisions of a "bunch of faithful hopefuls", then with the non decisions and negative actions on those that would do nothing and stagnate.
    And of course as long as the results remain "inconclusive" NASA and other orginisations will continue to search for more validity or otherwise to those inconclusive results on our behalf.......I certainly will continue to support them in that endeavour in whatever way I can.
    Last edited by ASTRO BOY; 2013-May-04 at 08:54 AM.

  5. #65
    Join Date
    Oct 2011
    Posts
    1,677
    Quote Originally Posted by Selfsim View Post
    The very wording implies that the search for life is the primary objective. That's what Viking was all about .. and look what we ended up with .. inconclusive results (which no-one can agree on), a bunch of 'faithful' 'hopefuls' unwilling to acknowledge the inconclusive outcomes, and the lead bio-testing design engineer attempting to resurrect his reputation by publishing seemingly endless sequels.

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

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

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

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

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

  6. #66
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by TooMany View Post
    And your point is what? Astrobiologists are idiots because 1) life cannot possibly exist elsewhere? 2) if it does, it will be so different that our silly instruments will not detect it? 3) Viking failed to conclusively detect life, so all efforts to conclusively verify it are futile? 3) if something is unknown it should not be pursued as though it might exist? 4) anything that is not directly known with certainty is "speculative" and therefore deserves no further research?

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

  7. #67
    Join Date
    Oct 2011
    Posts
    1,677
    Quote Originally Posted by ASTRO BOY View Post
    I don't believe we really have to worry too much about whether any or all of the above points are true within certain sectors of society.
    Coupled with the two variables of politics and economics, they may tend to slow things down some, but in the end the search will continue for ET life as well as going where we have not gone before.
    No amount of negativity or pessimism will halt either of those goals.
    Some are even saying that positive evidence of ET life will be found within our lifetimes.
    And even if that prediction fails to come to fruition, the sheer size in numbers and extent of the Universe, will see the search continue culminating with manned efforts and manned stellar exploration beyond our solar system.
    That put simply is our destiny.
    Indeed I agree with you. Optimists will make the advances and there are always the naysayers in any endeavor. I was just curious about the motivation. It is a common stance, not unique to Selfsim.

  8. #68
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by TooMany View Post
    I was just curious about the motivation. It is a common stance, not unique to Selfsim.

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

  9. #69
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by TooMany View Post
    0) And your point is what? Astrobiologists are idiots because 1) life cannot possibly exist elsewhere? 2) if it does, it will be so different that our silly instruments will not detect it? 3) Viking failed to conclusively detect life, so all efforts to conclusively verify it are futile? 4) if something is unknown it should not be pursued as though it might exist? 5) anything that is not directly known with certainty is "speculative" and therefore deserves no further research?
    (My numbering changes in bold .. to add precision and clarity to your query).

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

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

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

  10. #70
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by Selfsim View Post

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

    People can do and think whatever they like. I am no exception. I encourage people to think in a more disciplined and more productive way .. as opposed to being motivated from the initial, predestined principle of: "I think .. therefore it is"
    And yet science and cosmology procede on assumptions that are literally taken as truth or known...Why???...Becuase in many cases even though something may not be directly known, the data available makes its existence overwhelmingly positive.........Overwhelmingly enough to realise that although there is a non zero chance the answer maybe not what is expected, it's a reasonably safe bet and it's reasonably safe to procede under the assumption that the existence is positive.
    And that to put it simply is why we will still search for bacterial life on Mars now, and life elswhere in the solar system on many promising environments....Imagine, Speculate, search and research.....That's science, ask Albert Einstein.

  11. #71
    Join Date
    Nov 2008
    Posts
    2,511
    The necessity of compromise assures that a microscope is going to be sent to Mars. If one isn't sent, then there won't be as much support for missions. May as well start drawing it up. Those who believe in the possibility of life search for it, and those who don't search to implant it. Those who are interested in exploration are a mixed group of both types.

  12. #72
    Join Date
    Oct 2009
    Posts
    1,360
    Quote Originally Posted by Selfsim View Post
    (3) Viking's tests were designed from a flawed principle,....
    Dare to explain more about what you mean about "flawed principle"?
    Quote Originally Posted by Selfsim View Post
    They allowed for the possibility of a non-result, due to a lack of prior necessary and sufficient data, needed to isolate the samples from their native environment. This allowed for inconclusivity in associating the results with the samples.
    No,that is the insensibility of the GCMS (organic matter detection instrument) destined to find organic matter in the samples which caused the ambiguity about the LR results ... this is explained by Levin in the PDF page 5-6 ...the GCMS instrument which was conceived by another team, was set to detect organic content in the kinds of soils you might have in your backyard or in arable land,but totally unable to detect organic content in samples taken from Antarctica and from Siberia with active life that had the organic content of a few million cells per gram...-as demonstrated by tests made after the Viking mission using a similar GCMS organic matter detection instrument.-
    There was at least 30 attempts to find an explanation for the positive life detection results made by the LR instrument which turned around the mantra that it was chemistry rather than life. But none of these explanations were supported by peer reviewed papers.
    see this post from another thread for details
    http://cosmoquest.org/forum/showthre...58#post2118158
    Last edited by Don J; 2013-May-05 at 09:03 PM. Reason: clarity

  13. #73
    Join Date
    Oct 2011
    Posts
    1,677
    Quote Originally Posted by Selfsim View Post
    (5) Anything not directly known, is unknown. It doesn't simply exist because speculation says it does. Research commences from the observation of something, followed by its isolation from its surroundings. Looking for a ghost, doesn't result in the discovery of a ghost, simply because I once convinced myself that ghosts might exist!
    We have made many observations, particularly in the last century. We have learned much about life on earth and we understand the conditions under which it exists. We also have evidence of some similar conditions early on Mars. This makes it quite scientific to say that "life may have existed on Mars and may even still exist". This is something that we are trying to determine. It is nothing like your characterization of "looking for a ghost" which implies that the pursuit is unjustified or even absurd.

    Quote Originally Posted by Selfsim View Post
    People can do and think whatever they like. I am no exception. I encourage people to think in a more disciplined and more productive way .. as opposed to being motivated from the initial, predestined principle of: "I think .. therefore it is"
    In this instance you are absolutely wrong to state that this is an example of "I think ... therefore it is". So tell us, in this instance what would be productive.

    Quote Originally Posted by Selfsim View Post
    I'd say that comment is the beginnings of an ad-hom attack, and so I choose not to give it a serious response. Care to try again?
    You persistance in insulting researchers and all others involved in Mars exploration with the implication that they are making wild, unsupported speculations or chasing ghosts (in the field of astrobiology) has tried my patience.

  14. #74
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by Don J
    Quote Originally Posted by Selfsim
    (3) Viking's tests were designed from a flawed principle, (which others here, seem keen to repeat). They allowed for the possibility of a non-result, due to a lack of prior necessary and sufficient data, needed to isolate the samples from their native environment. This allowed for inconclusivity in associating the results with the samples.
    Dare to explain more about what you mean about "flawed principle"?
    Exactly what I said above (see underlined).

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

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

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

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

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

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

    Quote Originally Posted by Don J
    There was at least 30 attempts to find an explanation for the positive life detection results made by the LR instrument which turned around the mantra that it was chemistry rather than life. But none of these explanations were supported by peer reviewed papers.
    see this post from another thread for details
    http://cosmoquest.org/forum/showthre...58#post2118158
    There is now more data from Phoenix and other missions .. The Levin paper was published prior to Phoenix perchlorate results, also .. so it is now somewhat dated.

  15. #75
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by TooMany View Post
    We have made many observations, particularly in the last century. We have learned much about life on earth and we understand the conditions under which it exists. We also have evidence of some similar conditions early on Mars.
    .. And we have established no clear causal relationships between Earth's past environment and its causal role in the emergence of life. We have no feel for the sensitivites involved. As a result, we cannot say whether the past Martian environment would cause the same 'effects' as it did here.

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

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

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

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

  16. #76
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by Selfsim View Post

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

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



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

    Giving up on that search is not an option at this present time.
    Last edited by ASTRO BOY; 2013-May-06 at 09:30 AM.

  17. #77
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by ASTRO BOY View Post
    Actually all of science in general is about speculation, as well as Imagination, then forming hypothesis and then testing those hypothesis via experimentation and observation.
    That's just the way it is........
    Actually, when venturing into completely unexplored fields, the empirical methodology formally calls for large amounts of data to be accumulated before forming any speculative premise concerning the significance of the data, (or any expectations). Eventually, the investigation becomes less empirical and calls for more analysed, trended and historically condensed data. It also demands a high degree of your much beloved 'intuition' (from the investigator).

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

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

    This is the lesson learned, (by some), from Viking, and may well go some way to explaining why a follow-up mission has never eventuated, and why NASA has distanced itself from purely exo-life detection missions, since.
    (I get the feeling that Levin however, puts it more down to politics and conspiracies. I suppose that's his prerogative .. but its a difficult one to swallow, don't you think?)
    Last edited by Selfsim; 2013-May-06 at 11:25 AM.

  18. #78
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by Selfsim View Post
    Actually, when venturing into completely unexplored fields, the empirical methodology formally calls for large amounts of data to be accumulated before forming any speculative premise concerning the significance of the data, (or any expectations). Eventually, the investigation becomes less empirical and calls for more analysed, trended and historically condensed data. It also demands a high degree of your much beloved 'intuition' (from the investigator).

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

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



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



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






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


    Strange interpretations on your part. I do not believe NASA is distancing itself from any life detection missions or has ever done so.
    They have a job to do with many aspects, and I believe they are doing that and achieving excellent results.
    Levin has his own thoughts on the matter and I believe he feels strongly about them and I have some sympathy towards that view.
    To say he is proceeding because of politics and conspiracies would to me seem be the view of someone else with another view and agenda.
    Last edited by ASTRO BOY; 2013-May-06 at 09:13 PM.

  19. #79
    Join Date
    Oct 2011
    Posts
    1,677
    Quote Originally Posted by Selfsim View Post
    Your statement thus ignores this important and commonly adopted methodology in pure scientific research.

    Experimental methodology requires sufficient knowledge of the variables involved.

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

    This is the lesson learned, (by some), from Viking, and may well go some way to explaining why a follow-up mission has never eventuated, and why NASA has distanced itself from purely exo-life detection missions, since.
    (I get the feeling that Levin however, puts it more down to politics and conspiracies. I suppose that's his prerogative .. but its a difficult one to swallow, don't you think?)
    No you have it exactly backwards. Experimental methodology is used to gain knowledge of the variables involved. It takes lots of experiments to find out what's going on. You cannot preconceive a perfect experiment when you don't know what outcomes are possible. Sure we find out more about our ignorance by experimenting. That is no crime. Are you suggesting that you would have known how to do a much better experiment with the resources and knowledge available when the Viking project was building their experiment?

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

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

  20. #80
    Join Date
    Oct 2009
    Posts
    1,360
    Quote Originally Posted by Selfsim View Post

    The design of the GCMS should have catered for the detection of low concentration organics. Without this capability, no conclusions can be drawn.
    Why was it not calibrated to detect lower levels of organics? Somewhere, someone decided on a set of assumed design parameters, which may not have been valid in the selected Martian testing environment. How/why did this occur?
    The reason is that the GCMS was set to detect organic matter most scientists (still) believe exist on Mars (from meteoric impacts and infalls of interplanetary dust particles)
    Quote Originally Posted by Selfsim View Post
    The GCMS instrument should have been capable of detecting organics in the sample area (if present).

    If it wasn't, then clearly it wasn't capable of supporting the LR results, and thus the whole life detection strategy was flawed.
    Ya can't have the type of life being targetted, without having organics present ... so we can't rely solely on the LR results, without the confirmation of organics.
    No, the reason the CGMS was unable to detect organic matter in the Viking samples is because the CGMS was 8 orders of magnitude lower in sensitivity than the LR instrument for the reasons given above.
    Quote Originally Posted by Selfsim View Post
    Taken together, the GCMS and LR results still lead to an inconclusive interpretation.
    But it is strange that when NASA was aware for the fact that the CGMS was badly conceived they simply chosed to ignore that fact....and as you pointed out NASA rather chosed to distance itself from any other attempt at life detection on Mars?
    Quote Originally Posted by Selfsim View Post
    Experimental methodology requires sufficient knowledge of the variables involved. Different trials are strictly manipulated, so that inferences can be made as to causation of the observed change that results. This is precisely why the Viking experiments did not return conclusive results .. knowledge of the variables involved was incomplete and the GCMS calibration/sensitivity was set lower than the LR experiment's, as a result. In spite of later findings about why GCMS didn't detect organics, the Viking experience had already alerted many scientists as to just how ignorant science was about exo-life instrumentation/experimental design.
    It would have been easy to correct the GCMS calibration/sensitivity and send another Viking mission in the same area ...
    Last edited by Don J; 2013-May-07 at 04:14 AM. Reason: typo

  21. #81
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by Don J View Post
    The reason is that the GCMS was set to detect organic matter most scientists (still) believe exist on Mars (from meteoric impacts and infalls of interplanetary dust particles)
    Yes .. that's what Levin's report said .. but a more cohesive strategy would have been for it to have been calibrated so it could have supported or falsified the LR results, eh?
    (I think we might in loose agreement here?).

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

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

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

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

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

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

  22. #82
    Join Date
    Nov 2012
    Posts
    1,099
    Quote Originally Posted by Selfsim View Post

    .. Astrobiologists wanted to see life (but don't worry about the organics ..))..

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


    Quote Originally Posted by Selfsim View Post
    I personally don't 'blame' either camp. Viking, I think, was a premature attempt at testing exo-life hypotheses (and a rather expensive one at that).
    Why premature?


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

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

  23. #83
    Join Date
    Oct 2009
    Posts
    1,360
    Quote Originally Posted by Selfsim View Post

    Astrobiologists wanted to see life (but don't worry about the organics ..)).
    Very unlikely, proof of that is that Viking was equipped with a third life detection instrument the Pyrolictic Release (PR)which detected that organic matter was continously produced on Mars although the signal detected by this instrument was insufficient to be considered evidence for life,it clearly showed the on-going production of organic matter.Page-6 of the PDF.
    Post 1
    http://www.gillevin.com/Mars/THE_VIK...FE_ON_MARS.pdf
    Quote Originally Posted by Selfsim View Post
    Right .. but either way the GCMS results, (from the perspective from the LR results analysis team), was that there was no useful data (from GCMS) about the concentration of organics. So from their perspective, without that data, a fundamental piece of evidence was absent .. which ultimately thwarted the announcement of life. The net overall result is the same as if GCMS had detected no organics even if it had been calibrated at the same levels as the LR experiment.
    Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
    Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.
    Journal Of Geophysical Research PDF document:
    http://www.earth.northwestern.edu/pe...kay.viking.pdf
    Quote Originally Posted by Selfsim View Post
    from post #74
    There is now more data from Phoenix and other missions .. The Levin paper was published prior to Phoenix perchlorate results, also .. so it is now somewhat dated.
    About perchlorate... from Phoenix update page:
    http://martianchronicles.wordpress.c...-perchlorates/
    ....
    However, if the primary oxidizing agent is perchlorate, the news might not be quite so dire. Perchlorate is one of the slightly more benign oxidizers, since it tends to react more slowly than most. Also, if it was formed by breakdown of chloride salts at the surface, it probably is only present near the surface. Lower soil layers may not be as much at risk, and the deeper subsurface might be free of oxidants all together.
    Last edited by Don J; 2013-May-08 at 04:52 AM.

  24. #84
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by Don J View Post
    Very unlikely, proof of that is that Viking was equipped with a third life detection instrument the Pyrolictic Release (PR)which detected that organic matter was continously produced on Mars although the signal detected by this instrument was insufficient to be considered evidence for life,it clearly showed the on-going production of organic matter.Page-6 of the PDF.
    This result all depends on the type of oxidants present in the samples. One explanation was that oxidized iron, such as maghemite, could act as a catalyst to produce the results seen by the PR experiment.

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


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

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

  25. #85
    Join Date
    Dec 2011
    Posts
    3,317
    Just been reviewing the experiments and listening to some Levin YouTubes ...

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

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

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

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

  26. #86
    Join Date
    Oct 2009
    Posts
    1,360
    Quote Originally Posted by Selfsim View Post
    The other thing I find annoying about most of these reports, is that they use the highly nebulous term 'organics'. There are many types of organic compounds .. many of which are not bio-organics at all.
    The Journal Of Geophysical Research make it clear that it is organic carbon.
    http://www.earth.northwestern.edu/pe...kay.viking.pdf
    Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
    Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.

    Quote Originally Posted by Selfsim View Post
    The fact that both the GEX and PR experiments produced positive results even with the control sample, indicates that non-biological processes were at work in the soil.
    Can you point out to which control sample you are talking about with citation and reference ?Is the control sample giving exactly the same quantitative result?
    Last edited by Don J; 2013-May-09 at 02:11 PM.

  27. #87
    Join Date
    Dec 2011
    Posts
    3,317
    Quote Originally Posted by Don J View Post
    The Journal Of Geophysical Research make it clear that it is organic carbon.
    http://www.earth.northwestern.edu/pe...kay.viking.pdf
    Reanalysis of the Viking results in 2010 by the Journal Of Geophysical Research suggests perchlorate and organics...
    Page 1 Intro chapter: reinterpretation of Viking results suggest <0.1%Perchlorate and 1.5 to 6.5 ppm organic carbon at landing site 1 and <0.1%Perchlorate and 0.7 to 2.6 ppm organic carbon at landing site 2.
    Yeah .. but look at the organics they're talking about … chloromethane and dichloromethane. These things are industrial solvents like paint strippers, degreasers and aerosol propellants. Many represent toxicity to life, and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.

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

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

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

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

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

    Admittedly the paper was written in 1995, but it appears to summarise accurately much of the (somewhat dated) 'consensus mainstream' position detail, also elaborated upon in the Life on Mars Wiki page. (I chose this document 'cause it was a little easier reading and had a nice summary of the complexity .. but I don't limit my position on that basis alone).
    Last edited by Selfsim; 2013-May-10 at 12:13 AM. Reason: Deleted irrelevant text

  28. #88
    Join Date
    Nov 2012
    Posts
    1,099
    The Curiosity Rover like the other Mars Landers and Rovers in the past has pursued four main science goals and objectives.......

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

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

    [3]Determine the Martian geology

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

  29. #89
    Join Date
    Sep 2005
    Posts
    564
    Quote Originally Posted by Selfsim View Post
    Yeah .. but look at the organics they're talking about … chloromethane and dichloromethane. These things are industrial solvents like paint strippers, degreasers and aerosol propellants. Many represent toxicity to life, and to the best of my knowledge have little relevance to the presence or absence of microbial life functions.
    Uh, that is the standard definition of organic compounds (from wiki):
    "An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon (such as CO and CO2), and cyanides, as well as the allotropes of carbon such as diamond and graphite, are considered inorganic. The distinction between "organic" and "inorganic" carbon compounds, while "useful in organizing the vast subject of chemistry... is somewhat arbitrary".[1]

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

  30. #90
    Join Date
    Dec 2011
    Posts
    3,317
    Uh, that is the standard definition of organic compounds (from wiki):
    "An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon (such as CO and CO2), and cyanides, as well as the allotropes of carbon such as diamond and graphite, are considered inorganic. The distinction between "organic" and "inorganic" carbon compounds, while "useful in organizing the vast subject of chemistry... is somewhat arbitrary".[1]

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

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

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

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

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •