Results 1 to 12 of 12

Thread: Methane on Mars

  1. #1
    Join Date
    Aug 2003
    Posts
    2,092

    Methane on Mars

    New information on Martian methane. Interesting, but still not evidence of life.
    https://www.jpl.nasa.gov/news/first-...ethane-mystery

  2. #2
    Join Date
    Aug 2010
    Posts
    2,369
    Quote Originally Posted by Superluminal View Post
    New information on Martian methane. Interesting, but still not evidence of life.
    https://www.jpl.nasa.gov/news/first-...ethane-mystery
    It's evidence of a cycle of reactions: methane being produced in unknown ways, and broken down faster than expected.

    On Earth we not only have microbes that produce methane (methanogens), we also have species that consume it (methanotrophs).

    While the findings you've linked to are not proof of life on Mars, they're consistent with the hypothesis that Mars has life.

  3. #3
    Join Date
    Dec 2011
    Posts
    3,619
    Quote Originally Posted by Colin Robinson View Post
    .. While the findings you've linked to are not proof of life on Mars, they're consistent with the hypothesis that Mars has life.
    .. 'consistent with the hypothesis that Mars might have life', that is(?)

    On a related tack, I notice a recent release about Enceladus' methane (paper here). The interesting thing about this study, is that they've concluded that the similar Enceladus 'methanogenic life' hypothesis, is dependent on the probability of life emergence 'being high enough' there in the first place, (whatever that means).

    In the case of Mars though, I would say the probability of such life emergence there, is reasonably higher than it might be for Enceladus(?), so if it turns out that no signs of past life are found there with probe findings over the next 5 years or so, (and given past Mars probe findings), then the Enceladus' methanogenic life hypothesis would logically, correspondingly, have to diminish to a pretty insignificant level?:

    Observations from NASA’s Cassini spacecraft established that Saturn’s moon Enceladus has an internal liquid ocean. Analysis of a plume of ocean material ejected into space suggests that alkaline hydrothermal vents are present on Enceladus’s seafloor. On Earth, such deep-sea vents harbour microbial ecosystems rich in methanogenic archaea. Here we use a Bayesian statistical approach to quantify the probability that methanogenesis (biotic methane production) might explain the escape rates of molecular hydrogen and methane in Enceladus’s plume, as measured by Cassini instruments. We find that the observed escape rates (1) cannot be explained solely by the abiotic alteration of the rocky core by serpentinization; (2) are compatible with the hypothesis of habitable conditions for methanogens; and (3) score the highest likelihood under the hypothesis of methanogenesis, assuming that the probability of life emerging is high enough. If the probability of life emerging on Enceladus is low, the Cassini measurements are consistent with habitable yet uninhabited hydrothermal vents and point to unknown sources of methane (for example, primordial methane) awaiting discovery by future missions.

  4. #4
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    39,923
    Quote Originally Posted by Selfsim View Post
    .. 'consistent with the hypothesis that Mars might have life', that is(?)
    A hypothesis is already a "might". No need to repeat it.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  5. #5
    Join Date
    Dec 2011
    Posts
    3,619
    Quote Originally Posted by Noclevername View Post
    A hypothesis is already a "might". No need to repeat it.
    Just checking to see if we're all on the same page .. about something.
    Can't hurt repeating it for that reason, can it?

  6. #6
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    39,923
    Quote Originally Posted by Selfsim View Post
    Just checking to see if we're all on the same page .. about something.
    Can't hurt repeating it for that reason, can it?
    There are two possibilities we can present a hypothesis for. Mars has life, or Mars does not have life. One is true or the other is true.

    Waffling that Mars might have life is not a hypothesis. It's a belief.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  7. #7
    Join Date
    Mar 2004
    Posts
    20,578
    Quote Originally Posted by Selfsim View Post
    Just checking to see if we're all on the same page .. about something.
    Can't hurt repeating it for that reason, can it?
    I’m not sure if we’re on the same page, but I think it is fair to say most of the posters here understand what “hypothesis” means.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  8. #8
    Join Date
    Dec 2011
    Posts
    3,619
    Good grief!

    Isn't anyone here interested in commenting on the commonalities of the respective Mars and Enceladus 'methanogenic lifeform' hypotheses?

  9. #9
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    39,923
    Quote Originally Posted by Selfsim View Post
    On a related tack, I notice a recent release about Enceladus' methane (paper here). The interesting thing about this study, is that they've concluded that the similar Enceladus 'methanogenic life' hypothesis, is dependent on the probability of life emergence 'being high enough' there in the first place, (whatever that means).

    In the case of Mars though, I would say the probability of such life emergence there, is reasonably higher than it might be for Enceladus(?), so if it turns out that no signs of past life are found there with probe findings over the next 5 years or so, (and given past Mars probe findings), then the Enceladus' methanogenic life hypothesis would logically, correspondingly, have to diminish to a pretty insignificant level?:
    The two cases seem unrelated to me. They are different worlds (literally and figuratively) separated by several AU, with totally different conditions except they both have/had liquid water. What other commonalities do you see?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  10. #10
    Join Date
    Dec 2011
    Posts
    3,619
    Quote Originally Posted by Noclevername View Post
    The two cases seem unrelated to me. They are different worlds (literally and figuratively) separated by several AU, with totally different conditions except they both have/had liquid water.
    Please note: I acknowledge you said 'had' there, (which would cover the Mars case).

    Just as an update though, the idea that Mars currently still has any significant liquid water is being reconsidered. Other interpretations of the primary evidence source, which was taken from orbital radar sensors, have recently been proposed. The evidence for large surface bodies of liquid water in Mars' past, is pretty solid.

    If they conclude that the original interpretation of current significant bodies of liquid water, (eg: sub southern polar ice cap), was driven more by hasty optimism, this then impacts the broader interpretation of potential biogenic sources of Mars' methane.
    The estimation of the likelihood of biogenic sources of methane on other bodies, by way remote (spectrographic/radar) sensing, would also acquire another degree of scrutiny/checking, if this is so concluded.

    Quote Originally Posted by Noclevername
    What other commonalities do you see?
    I'd say that depends on the scale of focus of one's chosen model/hypothesis being considered (ie: the Enceladus study's Bayesian priors) .. I'm thinking of the terms of probability estimation equations here .. (eg: the fraction of bodies having planetary atmospheres consisting of one or more detectable 'bio-signature' gases, and the fraction of potential life forms that might actually produce planetary atmospheres with one or more detectable signature gases, in particular).

  11. #11
    Join Date
    Mar 2008
    Posts
    677
    A possible role for “sniff and dig”?

    A recent paper, that still needs peer review, suggests the possibility that Curiosity might be a dozen or so miles from a methane emission source. Night time emissions are suggested while scrubbing seems to happen in day time. It can not yet be claimed that the gas is actually currently being produced either by biological or non-biological methods. Gas trapped in clathrates in the near subsurface may be a source if the ice cage is being compromised.

    Mars Methane Sources in Northwestern Gale Crater
    Inferred from Back-Trajectory Modeling

    https://www.researchsquare.com/artic...icle/rs-569847

  12. #12
    Join Date
    Dec 2011
    Posts
    3,619
    Another report today constrains all of four so-called, exo bio-marker gases, (methane, ethane and ethylene and phosphine), down to below non-significant levels, by ESA's ExoMars Trace Gas Orbiter. (The methane conclusion is based on 2.7 Earth years of orbital readings).

    Nice summary graphic attached below. (Should be zoomable, I think?).

    The question is: What is the source of Curiosity's readings?
    I notice that, always missing from these reports, is analysis of any possible impacts from Curiosity's past leaking organic solvents issue, (from the wet front end of the SAM lab), which seems to have been largely forgotten(?) Got no idea if this has significance or not?

    Three papers supporting the above ESA conclusions:
    i) F. Montmessin et al, A stringent upper limit of 20 pptv for methane on Mars and constraints on its dispersion outside Gale crater, Astronomy & Astrophysics (2021). DOI: 10.1051/0004-6361/202140389;
    ii) Elise W. Knutsen et al, Comprehensive investigation of Mars methane and organics with ExoMars/NOMAD, Icarus (2020). DOI: 10.1016/j.icarus.2020.114266;
    iii) K. S. Olsen et al, Upper limits for phosphine (PH3) in the atmosphere of Mars, Astronomy & Astrophysics (2021). DOI: 10.1051/0004-6361/202140868
    Attached Images Attached Images

Posting Permissions

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