Forgot your password?
typodupeerror

A New Angle on Martian Methane 95

Posted by CowboyNeal
from the gassy-mysteries dept.
dusty writes "A recent hypothesis paper entititled 'Martian CH4: Sources, Flux, and Detection' delves into the production of methane on Mars. This hypothesis compares Mars with South Africa, and draws the conclusion that the radiolysis of martian ice and water while reacting with carbon dioxide can produce enough methane to account for recently observed concentrations. Methane is important because it is hard to explain. It has a short half-life and must be replenished frequently. As recently as 2005 the public line from NASA/JPL was that the methane could be produced by volcanism. Mars' dormant Olympus Mons is the largest volcano in the solar system but auspiciously quiet. A recent study from NOAA throws into question the whole idea stating, 'If Mauna Loa is a valid terrestrial analog, our findings suggest that volcanic activity is not a significant source of methane to the Martian atmosphere.'"
This discussion has been archived. No new comments can be posted.

A New Angle on Martian Methane

Comments Filter:
  • by Anonymous Coward
    And now we're here discussing Martian methane. Hooray for fart jokes!
  • by 3.5 stripes (578410) on Friday October 06, 2006 @07:26AM (#16334541)
    as anyone with 3 male roommates can testify to.
    • There's a lot of sci-fi shows that say the aliens breathe methane to live. Well since we fart methane and breathe oxygen, do martians breathe methan and fart oxygen?

      We could use each other as space suits.
      • by Gilmoure (18428)
        "Hey Froolak, I have an EVA to do. Mind if I stick my head up your ass?"

        Um...I think I'll wait for body mods so that I don't require constant breathing in space.
        • You wouldn't have to stick your head in there. Just put your face close enough and the aliens would do the same.
          • by Gilmoure (18428)
            I was thinking of a way to maintain positive pressure around the various holes humans seem to carry around with their heads. I guess it would be easier to drive a space scooter if you could actually use optical receptors that aren't just registering Froolak's last meal.
  • It has a short half-life and must be replenished frequently.

    Methane has a short half-life? I thought only radioactive elements had "half-lifes". Either I am just dumb about this (entirely possible) or someone chose their words poorly.
    • Re:Radioactive? (Score:4, Informative)

      by MichaelSmith (789609) on Friday October 06, 2006 @07:31AM (#16334577) Homepage Journal
      I thought only radioactive elements had "half-lifes".

      The term can be applied to anything which decays with time, though radioactive decay would probably give the most attractive decay curve.

      • Re:Radioactive? (Score:5, Insightful)

        by radtea (464814) on Friday October 06, 2006 @10:09AM (#16335925)
        The term can be applied to anything which decays with time, though radioactive decay would probably give the most attractive decay curve.

        You get the same curve from anything that has a probability of decay that is independent of time.

        If the probability of decay, destruction or loss for an individual atom is L per unit time, then for N atoms the rate of change of N is:

        dN/dt = -L*N

        and integrating gives N = No*exp(-L*t) where No is the number of atoms at some arbitrary t=0.

        So for any situation where you have a constant decay probability you will get the same curve. For methane in the Martian atmosphere the rate of decay is pretty much constant due to solar ultra-violet radiation breaking up the molecules. Therefore, if there were no source the amount of methane in the atmosphere would drop exponentially.
      • by Gilmoure (18428)
        Hubba, hubba! Check out the decay curves on that isotope! Wowzers!
      • Re: (Score:3, Funny)

        by Conare (442798)
        While radioactive elements give a more attractive decay curve, Methane smells more like decay, and is thus less attractive to those with curves.
    • by Cyberax (705495)
      The article means half-life of methane in atmosphere of the Mars.
    • Re: (Score:3, Insightful)

      by MadCow42 (243108)
      According to the article (first paragraphs even...), Methane is chemically broken down by sunlight over a few hundred years.

      MadCow.
    • Re:Radioactive? (Score:4, Informative)

      by B5_geek (638928) on Friday October 06, 2006 @07:38AM (#16334615)
      It's been awhile since biology class, but I'll do my best.

      UltraViolet radiation/light breaks down the Hydrongen bonds in Methane (CH3) thus 'destabalising' the molecule.
      Mars has no ozone layer too, (which blocks a large % of ground-level UV)
      • Well, if you got that from Biology, no wonder it's a bit off! I'll give the chemist's take on it - you've got the UV bit right, but hydrogen bonds don't exist in methane, which is CH4 (CH3 is a methyl group) What it can do is break the covalent bonds between carbon and hydrogen atoms, splitting the molecule. I don't know for sure, but intuition tells me you'll get a CH3- anion, and a H+ cation. Not sure though, you might get a carbocation...
        • Re: (Score:2, Informative)

          by cyclopropene (777291)
          I don't know for sure, but intuition tells me you'll get a CH3- anion, and a H+ cation. Not sure though, you might get a carbocation...

          It's a "homolytic cleavage"--they split as two radicals:

          H3C-H ---> H3C. + .H

          • by Moofie (22272)
            AHA! See? Gay marriage is going to RUIN CHEMISTRY!
          • Ahh right, I knew that was a possibility from the initiation of Cl. radicals. I thought that the relative electronegativities of the halogens in CFCs was responsible for allowing homolytic fission - I presume that's something else, though, perhaps bond strength.
      • Once radiation breaks the (covalent) bond with one of the (four) hydrogen atoms in the methane molecule, the hydrogen won't last long. Hydrogen is light, floats to the top of the atmosphere, and gets lost into space. Water is at risk too, but it's a really tough molecule and we started with a lot of it (and it freezes and falls back down while it's still low enough in the atmosphere to have some protection from radiation).
    • Re: (Score:3, Informative)

      by mykdavies (1369)
      The concept originated in the study of radioactive decay, but applies to many other fields as well, including phenomena which are described by non-exponential decays.

      See http://en.wikipedia.org/wiki/Half-life [wikipedia.org]
    • Raw UV radiation causes methane to convert to more stable water and carbon dioxide.
  • No life? (Score:4, Interesting)

    by Life700MB (930032) on Friday October 06, 2006 @07:28AM (#16334557)

    All that looong summary and no mention of the most interesting posibility: that the methane is life-generated by bacteria and the like living under the Martian soil.

    --
    Superb hosting [tinyurl.com] 200GB Storage, 2_TB_ bandwidth, php, mysql, ssh, $7.95
    • Re:No life? (Score:4, Insightful)

      by z0idberg (888892) on Friday October 06, 2006 @07:33AM (#16334593)
      I think the point is that the source of methane could potentially have been produced by living organisms but there is no other evidence at all of living organisms. Hence the search for what else could be the source.
      • Re:No life? (Score:4, Insightful)

        by MichaelSmith (789609) on Friday October 06, 2006 @07:42AM (#16334629) Homepage Journal
        methane could potentially have been produced by living organisms

        Given that we know the rate of destruction of Methane on Mars we also know the rate of production, which should make it possible to estimate the mass of Methane producing bacteria, assuming that is the source.

        • Well, easy to guess, that those scientists already did this, compared this to data about the amount of living organisms or their remnants detected so far and decided, that it is highly improbable, that they exist at all! Thus the search for other possible sources of methane...
        • by kestasjk (933987)
          That would require a great deal of knowledge about the bacteria; mostly their metabolism and food sources.
          • sorry to disappoint you: you don't have to have a lot of knowledge. Every biological production of methane (or any other substance) is in its nature a chain of chemical reactions. While the characteristics of life may differ on different planets, chemistry always stays the same- giving you at least the energy demand (or benefits) of a reaction that gives the detected amount of CH4 in an environment likes Mars' atmosphere from the substances there.
            To make an estimation about how much living mass would be a
      • by alexo (9335)
        Everybody knows that Martian Methane is produced by Martian cows.
        • by Gilmoure (18428)
          But are they happy cows? Did they vote for that guy who came to mars and had his eyes bug out?
      • by SirBruce (679714)

        I think the point is that the source of methane could potentially have been produced by living organisms but there is no other evidence at all of living organisms. Hence the search for what else could be the source.

        Given that the ONLY experiment ever designed to specifically test for life on Mars had a POSITIVE RESULT, I think it's highly misleading to say that there is NO evidence for living organisms on Mars. Remember, just because there is evidence for something doesn't mean that something is true. It

    • by MtViewGuy (197597)
      There are a number of Mars lander missions planned by NASA and ESA that will try to answer that very question. The new rovers will drill up to 100 cm under the surface and a new generation of chemical analyzers will look at the chemical results from that deep in the soil. It's likely that small microbes could live in the Martian soil using small amounts of water moisture trapped in the soil.
      • Re:No life? (Score:5, Informative)

        by Rei (128717) on Friday October 06, 2006 @12:14PM (#16337547) Homepage
        No, it's not likely. Everything that we've come to learn about Martian regolith is that it's highly oxidative -- peroxides, superoxides, etc. Then factor in the problems we've known for a long time -- radiation, temperatures, lack of liquids, etc.

        If there's any life there, it must be extremely different from life on Earth to be able to withstand the oxidative environment. On Earth, Martian regolith would be a disinfectant.

        Besides, volcanism and this new theory aren't the only viable ones for methane production. Serpentization of olivine will do the trick as well. That is to say, if anywhere on the planet there is subsurface water saturated with CO2 in ever-common olivine-rich rock, it will produce methane.
        • Re:No life? (Score:5, Informative)

          by SirBruce (679714) on Friday October 06, 2006 @01:21PM (#16338591) Homepage
          Ahhh, the old "highly oxidative" argument.

          In truth, there has never been a test on a Martian lander designed to either confirm or identify the nature of this hypothetical strong oxidant. While there are theories that suggest that UV light should create such oxidants, the presence of a higly oxidant Martian surface has never been confirmed by experiment. Rather, it has been invoked as an EXPLANATION why certain other results, such a the Viking LRE, must be faulty.

          To date, no subsequent Mars probe has produced data that points to a strong global surface oxidation beyond the usual culprits of H20 and CO2 (which account for the rust).

          Bruce
          • Re: (Score:3, Informative)

            by Rei (128717)
            Not only UV, but also dust devils. Experiments on simulated dust devils show that they produce about 200 times more H2O2 than UV does.

            H2O2 *has* been detected on Mars. In 2003, the IR TEXES spectrometer team detected 20-50 ppb of H2O2 in the atmosphere. The James Clerk Maxwell Telescope confirmed this. Since it doesn't last long in the atmosphere, this means that it's constantly being produced. H2O2 bound to dust particles would end up in the soil, so this observation is consistant with theory.

            In short
            • by SirBruce (679714)
              In short, we have lab experiments creating H2O2 on Mars and observations confirming what we'd expect. What more do you want?
              Better life detection experiments on the ground, like a new version of the LRE. As you point out, MSL will be helpful here, but it took NASA 30 years to revisit the issue.

              Bruce

        • by MtViewGuy (197597)
          The problem is that when Viking did its soil sampling it did it only on the very surface of the topsoil, which may not have enough water and is too exposed to UV rays from the Sun to support even microbes. This is why I suggest drilling down 100 cm into the soil--at that point, there may be still enough water trapped in the soil to support primitive microbial lifeforms.
  • Beans... (Score:2, Funny)

    by teh loon (974951)
    It just goes to show that Martians like beans... A lot.
    • Beans, beans,
      The musical fruit.
      The more you eat.
      The more you toot.

      [Someone had to say it.]
      • Beans, beans,
        They're good for your heart.
        The more you eat,
        The more you fart.

        There, corrected it for you.
        • by nebbian (564148)
          Baked, beans,
          Are good for the heart.
          Baked, beans,
          Make you fart.
          The more you fart,
          The better you feel,
          So eat, Baked beans,
          For every meal!

          There, corrected it for you.
      • The more you toot,
        The better you feel,
        So be sure to eat beans
        With every meal!
  • Good science (Score:5, Insightful)

    by Da3vid (926771) on Friday October 06, 2006 @08:23AM (#16334863)
    "'If Mauna Loa is a valid terrestrial analog, our findings suggest that volcanic activity is not a significant source of methane to the Martian atmosphere.'"

    Man, I wish more of our scientific quotes sounded like this one. It lays it out straight and simple. Here is our source of info: analogy with Mauna Loa. Here is our assumption: we can project info from it onto Olympus Mons. Here is our conclusion: there is something else other than volcanic activity producing methane on Mars. I like how all that info was neatly packaged into a simple sentence. I also like how he admits the assumption... if. The thing that comes to mind are all the dinosaur shows explaining their day to day lives, zodiac signs and favorite take-out places.
  • "This hypothesis compares Mars with South Africa". Being from South Africa I take offense at this. How can you compare a dry harsh violent place such as Mars to our country ? Oh , wait...nevermind.
  • by hb253 (764272)
    Auspiciously quiet?
  • Thomas Gold (Score:3, Interesting)

    by BenJeremy (181303) on Friday October 06, 2006 @09:48AM (#16335661)
    Didn't Thomas Gold postulate that we'd find lots of methane on Mars? He had many intriguing theories on "deep life" - and recent evidence of "replenishment" of petroleum reserves, IIRC, while puzzling to geologists following the standard theories, would not have been a mystery to him.
    • by vtcodger (957785)
      Did Gold predict methane on Mars? Most likely. He's predicted it just about everywhere else. Mostly, he's been wrong. One can make a pretty good case that if you shoot enough arrows you're bound to hit something occasionally.
    • Didn't Thomas Gold postulate that we'd find lots of methane on Mars? He had many intriguing theories on "deep life" - and recent evidence of "replenishment" of petroleum reserves, IIRC, while puzzling to geologists following the standard theories, would not have been a mystery to him.

      Dr. Gold was also convinced that the Moon was covered in dust many meters deep - after the Surveyor landings showed that to be incorrect, he changed his belief to 'the moon is covered in dust with a crust just thick enough to

  • Time to take the War on Drugs to Mars. Can't have those evil martians poisoning our children! Oh, it's methANE, you say? Nevermind.
  • (Need to revive old thread :-)
  • If Mauna Loa is a valid terrestrial analog, then Mars will soon be providing us with delicious macadamia nuts.
  • Just a heads up, TFA is a bloaty PDF.

Of course you can't flap your arms and fly to the moon. After a while you'd run out of air to push against.

Working...