A New Angle on Martian Methane

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.'"

Re:Radioactive?

[MichaelSmith]

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?

[B5_geek]

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)

Re:Biggest Volcano

[tomhudson]

The solar system's biggest volcano is Loki on Jupiter's moon Io.

Nope. Its "the most powerful". While they might cover the same surface area, Olympus Mons stands much higher.

Re:Radioactive?

[mykdavies]

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]

Re:This is interesting...

[Eunuchswear]

Ok,

1. just turning C02 + H2O + energy -> CH4 + ...
   would be seriously dumb as CH4 is a much more potent greenhouse gas than C02, and stockpiling it would harder than just stockpiling the CO2 in the first place.
   
2. and turning C02 + H20 + energy -> CH4 then burning the CH4 to get C02 + energy is just a nice way of wasting energy.
   
3. You're not talking about a power source, just an expensive and dangerous power transmission medium.
   
4. And finaly, what on earth do you mean by fragile biological processes? Artificial processes are way more fragile than biological ones.
   

Re:Radioactive?

[cyclopropene]

Well you probably wanted to say intramolecular C-H bond instead of hydrogen bond, which is a kind of intermolecular bonding...

Hydrogen bonds certainly can be intramolecular. Intramolecular hydrogen bonds are a significant part of what holds a folded protein in its shape.

Re:Radioactive?

[cyclopropene]

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

Re:No life?

[Rei]

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?

[SirBruce]

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:No life?

[Rei]

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, we have lab experiments creating H2O2 on Mars and observations confirming what we'd expect. What more do you want?

it has been invoked as an EXPLANATION why certain other results, such as the Viking LRE, must be faulty

Incorrect. It was initially proposed to *make sense* of the results of the Viking LRE. The results were inconsistent with any pre-test predictions.

To date, no subsequent Mars probe has produced data . . .

None of the surface probes thusfar have been *equipped* to detect peroxide or superoxides except in massive quantities. MSL, however, will be.