Become a fan of Slashdot on Facebook

 


Forgot your password?
Close
typodupeerror
×
Mars Space

Martian Methane May Come From Rocks 147

Posted by Zonk from the as-opposed-to-critters dept.
An anonymous reader writes "When methane was found in the Martian atmosphere last year, some scientists thought this was indirect evidence of methane-producing bacteria. But minerals such as olivine can create methane in a process known as serpentinization. Geologists calculated that a global, 50-centimetre-thick layer of olivine could account for the methane. One geologist said, 'I'd love to see bugs, but you can't just go on hope. You have to consider the geological options.' Other scientists are unsure whether methane on Mars even exists."
This discussion has been archived. No new comments can be posted.

Martian Methane May Come From Rocks More

Martian Methane May Come From Rocks

Comments Filter:

  • as the song says... (Score:5, Funny)

    by Tumbleweed ( 3706 ) * on Monday June 06, 2005 @01:25AM (#12733354)
    "Cows on Mars." *dunh dunh dunnnhhh*

    Look, if a cow can jump over the Moon, it's not much of a stretch to think they can get to Mars. Getting out of the Earth's gravity well is most of the challenge, really.

  • Maybe that layer is part of something else... (Score:5, Funny)

    by TheWanderingHermit ( 513872 ) on Monday June 06, 2005 @01:26AM (#12733359)
    Maybe that layer is planet wide, and part of a larger living organism that will one day be calling us ugly bags of mostly water.

    Well someone had to say it...

  • Terrestial Methane may come from Cows (Score:5, Funny)

    by xmas2003 ( 739875 ) * on Monday June 06, 2005 @01:26AM (#12733361) Homepage
    In a related story ...

    alek [komar.org] writes "When methane was found in the Terrestial atmosphere last year, some scientists thought this was indirect evidence of methane-producing bacteria. But animals such as bovines can create methane in a process known as breaking wind. Animalogists calculated that a global herd of 50,000 bovines could account for the methane. One animalogist said, 'I'd love to see udders, but you can't just go on hope. You have to consider the back-end options.' Other scientists are unsure whether methane on Earth even comes from cows."

  • Serpentinization: hint of water (Score:5, Insightful)

    by helioquake ( 841463 ) * on Monday June 06, 2005 @01:30AM (#12733369) Journal
    Serpentinization requires water to seep through rocks and to get oxidized. If this new interpretation of the existence of methane is indeed correct, then it clearly implies the existence of the large body of water in the recent past (or at present).

    So in either way it turns out, this is a cool finding.

    /i do have to wonder sometimes, though, how narrow-minded those astrophysicists/planetary scientists are, as opposed to those geologists who have to work really hard to match their theory/experiment with the abundant amount of sample data points on earth.
    • Many planetary scientists (for example Phil Christensen, quoted in the article) are in fact geologists by trade, and had to go through a rigorous earth-based geology program. /Incoming ASU grad student, planetary science.
    • I don't buy it. 1) yeah there was water there at one point in history but it's not around much anyomre in liquid form. 2) Mars is tiny, less than 20% the size of the earth, while there was at one time tectonic activity which could have provided the necessary heat / pressure to do this, the planet is currently frozen solid and has been for some time. It just doesn't have the mass (like earth does...) to keep tectonic activity going on. 3) without a constant (and modern) method for creating this methane, i

      • Re:Serpentinization: hint of water (Score:5, Informative)

        by Kymermosst ( 33885 ) on Monday June 06, 2005 @03:43AM (#12733740) Journal
        I don't buy it.

        I do.

        Serpentinization is a low-temperature, low-pressure process where ultramafic minerals (like olivine) are introduced to water. They metamorphose into serpentine-group minerals. It is a common surface to near-surface process on Earth. (It is the opposite of most other metamorphic reactions, where an increase of pressure/temperature causes the change... in this case, it is the decrease.)

        1) yeah there was water there at one point in history but it's not around much anyomre in liquid form.

        Yes, but we don't know what is below the surface. It is likely that mars is still fairly warm in the middle due to remnant heat and radioactive decay.

        2) Mars is tiny, less than 20% the size of the earth, while there was at one time tectonic activity which could have provided the necessary heat / pressure to do this, the planet is currently frozen solid and has been for some time. It just doesn't have the mass (like earth does...) to keep tectonic activity going on.

        Io, moon of Jupiter, is smaller than Mars and has ongoing tectonic activity. It has nothing to do with the mass of a body, it has everything to do with heat, which Mars has little of, for sure, but once had plenty of... look at Olympus Mons.

        There is no evidence that Mars is "frozen solid". It could still have a soft core. In any case, it is likely to be rather warm in the middle, still.

        3) without a constant (and modern) method for creating this methane, it all would have blown away like the rest of the Martian atmosphere, the planet is cold, nothing geologic is going on there anymore.

        I agree with the geologists. The explanation is rather simple: There isn't a whole lot of water on Mars, so water contact with olivine is scarce. Thus, the reaction is very slow. If there were sh*tloads of olivine in the subsurface Mars, and there may be, then serpentinization could go on for a long time.

        Why do I think there's a lot of olivine in Mars? Because there is a lot of olivine in the Earth. The bulk of the mantle is peridotite, an olivine-pyroxene rock.

        But wait, there's more! There might be a large amount of olivine on the surface of mars. Olivine is a quite common mineral to find in basalt flows on Earth, existing as phenocrysts or mantle xenoliths. Matter of fact, I was looking at some olivine crystals in some basalt in central Oregon yesterday.

        Now, bedrock exposures at the surface of Mars have been observed to be largely a basalt-like rock. In fact, it appears to be the main rock type on most of the surface of mars.

        (Interestingly enough, basalt also happens to be the most common crustal surface rock type on Earth, given that it is the surface rock of oceanic crust.)

        It may be that there is a large amount of olivine on Mars, and a limited supply of water would cause the reaction to be slow and sustained. It could go on for a long time.

        I'm not saying life does not exist, in fact I defended the idea in my Slashdot journal a year or so ago, but I wouldn't pin all the methane production on life when another simple explanation exists.

        • Good post

          (It is the opposite of most other metamorphic reactions, where an increase of pressure/temperature causes the change... in this case, it is the decrease.)

          A lot of mafic minerals stable at high P&T are unstable(or metastable) at lower P&T.

        • Io, moon of Jupiter, is smaller than Mars and has ongoing tectonic activity. It has nothing to do with the mass of a body, it has everything to do with heat,

          Io's in a purely unique situation from Mars.

          Unlike Mars, Io is also being heavily irradiated and gravitationally tugged at by a massive gas giant (Jupiter). Depending on the composition and orbit of a Jovian moon, these forces alone can be the cause for Io's activity.

          Jupiter's gravitational force is so strong, it's prevented the asteroid be

          • Io's in a purely unique situation from Mars.

            The original greatgrandparent post claimed solely due to Mars's size, it would be "frozen solid". The grandparent used Io as a counterexample. That point remains. Whether or not Mars is solid or has liquid water underneath the surface depends on how much heat it retains. But it will retain some heat.

        • There is no evidence that Mars is "frozen solid". It could still have a soft core. In any case, it is likely to be rather warm in the middle, still.

          I was under the impression than Mars has no appreciable magnetic field, and that a potential explanation for this was the dynamo of molten iron that the earth enjoys had cooled to solidification on Mars.

          • I was under the impression than Mars has no appreciable magnetic field, and that a potential explanation for this was the dynamo of molten iron that the earth enjoys had cooled to solidification on Mars.

            The key word is potential. I'm not saying that Mars has a liquid core... but perhaps a mushy "plastic" one.

            There should still be a lot of heat. Remember that the pressures we are talking about at a planet's core would mean many materials were solid to semi-solid at much higher temperatures than they wou
          • I was under the impression than Mars has no appreciable magnetic field, and that a potential explanation for this was the dynamo of molten iron that the earth enjoys had cooled to solidification on Mars.

            The core doesn't need to cool to the point it's solid just to shut down the dynamo. It is believed that Mars once had a magnetic field and the state of that field is now locked in the rocks of the crust.

            The interior could very well be molten, it could also be solid. It may be cool or it may be hot.

            The

      • Mars is likely not frozen solid [spacetoday.net]. Just because we don't see eruptions going on nonstop on a major scale doesn't mean that they don't occur in recent geologic history. If some alien started observing Earth a couple decades ago using that same logic, they would conclude that megatsunamis and supervolcanoes don't occur on Earth, that the Sahara has always been a desert, and that we've always had high carbon-13 concentrations in our atmosphere.
  • If we aren't sure, let's keep looking. Send up a few drilling robots and get some serious soil samples. Let's see if there's any water under that dusty ground.

    Investigating from a distance is fine for things we can't reach, but Mars is just around the corner, in astronomic terms. We spend all this time sending up little probes when what is needed is not Martian air samples, but Martian soil samples.

    Unfortunately it's not profitable to investigate other planets. The benefit to sending up rockets is pla

  • gassy rocks (Score:5, Funny)

    by pintomp3 ( 882811 ) on Monday June 06, 2005 @01:31AM (#12733379)
    my pet rock was also very flatulent

  • mars is a exobiological rorschach test (Score:4, Insightful)

    by eexlebots ( 203658 ) <eexlebots.subrevolt@com> on Monday June 06, 2005 @01:36AM (#12733401) Homepage
    I mean, one scientist looks at a meteor and says, "Oh good there is ancient Mars life in it, "and another looks at the same meteor and says, "Oh no that is a geologic process." One looks at the Viking lander data and says, "Oh check it out life!" and another says, "Nope just an unforseen nonbiotic chemical reaction." Now it is the same argument with Methane. Jeeze, we should just send some dudes over there and get this over with already...

  • only a 50cm layer? (Score:3, Funny)

    by ColaMan ( 37550 ) on Monday June 06, 2005 @01:53AM (#12733458) Journal
    Well, hell a 50cm layer of olivine covering a whole goddamn planet is totally feasible.

    I wonder why they didn't think of that before?

    • Re:only a 50cm layer? (Score:5, Funny)

      by 0racle ( 667029 ) on Monday June 06, 2005 @02:00AM (#12733480)
      You have a thick crust covering the whole goddamn planet so its not exactly hard to imagine that 50cm of it could be ovaltine, or whatever rock they said it was.
    • I wonder why they didn't think of that before?

      Do you know how much it cost per hour to ask a professional planet builder a question? And sometimes the answers don't make sense. For example, 42 what? :P
    • Well, hell a 50cm layer of olivine covering a whole goddamn planet is totally feasible.

      Why not? Our planet has a layer almost 400km thick of ultramafic rock, mostly peridotite.
    • That's probably not such a substantial amount of rock when compared with the total volume of Mars crust. But how much of Mars' crust actually shows signs of being derived from serpentinized rock? For this amount of methane to exist, it implies that the serpentinization has already taken place. Obviously, given our limited sample set, the answer is "we don't know".

      I also wonder how much water it would take to serpentinize that much olivine. (Any geologists/chemists?). Is it only a catalyst or does the water
  • Doesn't everybody know that "it was Julie"?
  • We won't get to welcome our new martian overlords.

  • Viking Landers (Score:3, Interesting)

    by jd ( 1658 ) <imipak@ y a hoo.com> on Monday June 06, 2005 @02:02AM (#12733489) Homepage Journal
    It has been known for some considerable time, as a result of experiments by the Viking Landers, that the soil had some interesting chemical properties. It is hardly news. However, methane from the rocks and clay cannot be the source, as the methane has been seen concentrated in small regions, whereas the rocks and soil are fairly uniform across the planet.

    • Re:Viking Landers (Score:5, Insightful)

      by Kymermosst ( 33885 ) on Monday June 06, 2005 @03:08AM (#12733658) Journal
      It has been known for some considerable time, as a result of experiments by the Viking Landers, that the soil had some interesting chemical properties. It is hardly news. However, methane from the rocks and clay cannot be the source, as the methane has been seen concentrated in small regions, whereas the rocks and soil are fairly uniform across the planet.

      Obvious solution: The methane isn't being formed at the surface.

      Serpentinization only requires that the olivine (more likely, peridotite - an olivine/pyroxene rock) be moved to cooler temperatures and lower pressures, with a bit of water to make the ions move.

      So, in your "small regions" where the methane is concentrated, you have some subsurface olivine and some water getting to it.

      Regarding that uniform rock and soil on the martian surface, consider flood basalts over eastern Oregon and Washington. The surface is made up of basalt, yes. However, underneath all that basalt, in many areas, is material that was buried by it.

    • Dear Viking Landers,

      "Bob" and I have been married for two years. When we first married, I moved into the home he had been living in for quite some time. The problem? He gave his parents a key to the house, and they are accustomed to using it whenever they wish. I need some advice
      -- Northern Belle

      Dear Belle,

      ARR! ARRR! Ordbøkene er utarbeidde ved Seksjon for leksikografi og målføregransking på Nynorskordboka er gitt ut på Det Norske Samlaget!!!!!

  • No life claim in original paper (Score:4, Interesting)

    by Greg Hullender ( 621024 ) on Monday June 06, 2005 @02:13AM (#12733536) Homepage Journal
    All that's new here is the specific mechanism using Olivine. The original paper considered both biologic and non-biologic processes.

    Here's the abstract of the original paper. I can't give a link because it requires a subscription to Science, but I think this is enough.

    Detection of Methane in the Atmosphere of Mars
    Vittorio Formisano,Sushil Atreya, Thérèse Encrenaz, Science, Vol 306, Issue 5702, 1758-1761, 3 December 2004

    We report a detection of methane in the martian atmosphere by the Planetary Fourier Spectrometer onboard the Mars Express spacecraft. The global average methane mixing ratio is found to be 10 ± 5 parts per billion by volume (ppbv). However, the mixing ratio varies between 0 and 30 ppbv over the planet. The source of methane could be either biogenic or nonbiogenic,including past or present subsurface microorganisms, hydrothermal activity, or cometary impacts.

    Later in the article, they expand on what they mean by "hydrothermal activity."

    On the other hand, methane could have been formed by magmatic processes or stored in methane hydrates for later release to the atmosphere. Terrestrial volcanoes are not a big source of methane, and large-scale volcanism has not taken place on Mars for over 100 million years. However, small-scale outgassing of methane cannot be ruled out. A potentially larger source of methane than volcanism may come from the alteration of basalt at a temperature <150C, a process that also results in the wet-phase conversion of original CO2 into CH4 in a subpermafrost aquifer. In their chemical equilibrium computer model, Wallendahl et al. calculate that as much as 0.2 bar, ~1015 tons, of CH4 could have been produced if the only source of C in this region was the CO2 initially present in the crustal pores. Methane could have been sequestered in stable methane hydrate and gradually risen to the planet's surface. The rate of release to the atmosphere is unknown, but if one assumes that leaking has been taking place at a uniform rate over time, it would amount to ~200,000 tons year-1, which is much greater than the 100 tons or so per year needed to maintain a steady-state mixing ratio of 10 ppbv of CH4 on Mars today. Even if methane from the hydrate is being released at a rate that is a factor of 1000 slower, it would still be sufficient to account for the observations. Finally, recent laboratory experiments confirm abiogenic generation of methane in mineral-catalyzed hydrothermal reactions of CO2 and H2O at 390C and 400 bars, conditions that are likely to be encountered in subpermafrost aquifers or deep under the polar ice on Mars. Moreover, the catalyst used in the experiment--Fe-Cr oxide--is also believed to be present in the martian rocks.

    Note that Olivine is Magnesium Iron Silicate (http://mineral.galleries.com/minerals/silicate/ol ivine/olivine.htm [galleries.com]), so that's not the same as the Fe-Cr considered here, but it's not all that far a stretch either.

    --Greg

    • The Globe and Mail did a story* [theglobeandmail.com] last week about this. All over the earth, there are deposits of methane trapped in ice, amounting to an
      estimated 565e12 ft^3.

      If something similar existed on mars, it could be slowly releasing methane.

      *The link seems to work for me about 1/2 the time, and half the time I'm sent to a 'Premium Content, Login Required Page'. Sorry.

  • Mars - The Christmas Planet (Score:5, Interesting)

    by Jah-Wren Ryel ( 80510 ) on Monday June 06, 2005 @02:14AM (#12733540)
    Olivine is green. See this picture of an isolated, but still somewhat famous, green-sand beach in Hawaii
    It is green because of all the olivine in the sand, been there myself a few times:

    http://www.letsgo-hawaii.com/beaches/GreenSand2_be ach.jpg [letsgo-hawaii.com]
    http://artemis.austincollege.edu/acad/bio/sgoldsmi th/hawaii02_images2/greensandbeach.jpg [austincollege.edu]

    If there really is that much olivine on the planet, we are going to have change the nickname from "the red planet" to "the christmas planet."
    • My mum always told me that methane is produced by something that is brown and sounds like a bell.

      Therefore, olivine must be not only green, but also brown. And I have no idea how it sounds.

  • In other news (Score:4, Funny)

    by gnovos ( 447128 ) <gnovos@ c h i p p e d . net> on Monday June 06, 2005 @02:26AM (#12733566) Homepage Journal
    Other scientists are unsure whether methane on Mars even exists.

    While many philosophers are unsure whether Mars exists at all, or if it's just a figment of thier imagination.

  • Secret decoder ring (Score:2, Funny)

    by Anonymous Coward
    Did anyone else read "50 centemetre layer of olvaltine?"
  • Am I the only one that read
    Geologists calculated that a global, 50-centimetre-thick layer of ovaltine could account for the methane.
    ?

  • Nonsense. Everyone knows martian methane (Score:4, Funny)

    by Anonymous Coward on Monday June 06, 2005 @02:34AM (#12733582)
    comes from Uranus. [ducks]
  • Damn! Now I must rip my doctoral thesis of how farting Martians have caused the methane.

  • Olivine may be biological (Score:3, Interesting)

    by Anonymous Coward on Monday June 06, 2005 @02:54AM (#12733627)
    There is a hypothesis doing the rounds that nanobacterial metabolism is responsible for depositing mineral plaques from solution.

    http://www.google.com.au/search?hl=en&q=nanobacter ia+olivine&btnG=Search&meta= [google.com.au]

    Notably, the microfossils found in the martian meteorite are thought to be of nanobacterial origin.
    • The large quantity of Martian volcanism means there is probably a lot of olivine near the surface produced through nonliving processes. Any olivine produced through living processes would be dwarfed by this IMHO.
  • Damn, who could have guessed that the most laughable concept from "Robinson Crusoe on Mars" -- the hero breaks Martian rocks apart to get breathable air -- is practically true?

    http://imdb.com/title/tt0058530/ [imdb.com]

    Course, the reality is, the real rocks are gonna smell like cow manure.

    I'll pass, thanks.
  • Finding life on Mars would be interesting and change much of the outlook of humanity however I think I would prefer that they don't find life on it. That would avoid the whole debate on the effect of teraforming on Martian life and if we should do it at all.
  • Most likely producer of methane on Mars?
    1. Rocks
    2. Bacteria
    3. Cows
    4. Cowboyneal
  • We must stop Al-Qaeda from turning all that methane into a planet-sized WMD fart-bomb!!! Please send money to K.Rove immediately. ;)

  • FYI (Score:1, Informative)

    by clawDATA ( 758072 )
    Olivine is olive-green.

    (I knew that geology elective would come in handy someday.)

  • Some chemist please... (Score:4, Interesting)

    by Vo0k ( 760020 ) on Monday June 06, 2005 @05:38AM (#12734031) Journal
    What process does produce the methane then?
    Olivine+Water -> Serpentine+Methane+?

    So:
    x*(Mg2SiO4) + y*(Fe2SiO4) + z*(H2O) -> a*(several longish formulas for different kinds of Serpentine) + CH4 + ?

    So where's the carbon coming from? I don't see any on the left side? All nice and pretty but carbon isn't all that common outside Earth, and is fundamental for building proteins - that is earth-like life, and there's no methane without carbon.

  • -no- (Score:1)

    by amiak ( 663900 )
    idon'tgiveashit(moreandmorehits)
  • "I'm a DOCTOR...not a BRICKlayer!"
  • ...Of the story I read a bit back about the earth-shattering revelation that apparently Mars is covered in rocks not unlike those which can be found in virtually any desert on our own planet.

    I propose that after the next E3, somebody round up all of the booth babes from that event that they can find, drive all of them to wherever it is the scientists who are producing these news stories are conducting their research, and then lock both the scientists and the booth babes in the research facility for the nex
  • Theres no carbon in olivine or water.
  • Would a living source of the methane impart a differential Carbon isotope ratio than non-living source?
  • To be "Martian Methane May Come From Rockets"?
    It seems plausible..

Slashdot Top Deals

For God's sake, stop researching for a while and begin to think!

Close