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.'"

Comments

Good science

[Da3vid]

"'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.

Re:Radioactive?

[radtea]

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.