Martian Methane May Be Created By Lifeforms

Following our recent discussions about the growing evidence pointing to possible life on Mars, reader skywatcher2501 writes with news of a study that has ruled out one possible explanation for the levels of methane seen on that planet — that it might be replenished by disintegrating meteors entering the atmosphere. So two theories remain: either the gas is created as a by-product of reactions between volcanic rock and water, or it is a by-product of a lifeform's metabolism.

Re:Questions:

[Yetihehe]

The problem is that on mars all methane should vanish in months due to oxidizing soil. Therefore something must be replenishing it.

Re:Underground methane leaking?

[mycroft822]

There are recent studies showing it may be possible that some of our methane on Earth is being created by the high pressure/temp conditions in the earth's mantle, rather than exclusively by the decay of organic matter. A written article [newenergyandfuel.com] on this, or an NPR segment [sciencefriday.com] (about 1/3 of the way into the audio file).

don't really understand the point

[khallow]

As I understand it, we know there's olivine on Mars [hawaii.edu] and that there's water on Mars [timesonline.co.uk]. Assuming the laws of physics operate the same on Mars as on Earth, then you have all the explanation you need for methane on Mars. Serpentinization [wikipedia.org] is the process of reacting olivine with water. It generates methane as a byproduct.

The question isn't whether serpentinization is a source of methane, but rather whether it is the majority source or not. My take is that if the methane production was due to life on Mars, there'd be a lot more methane being produced than a few hundred tons a day. I don't see life on Mars staying in one place over millions much less hundreds of millions of years. But I suppose there's a chance it could happen that way (say if life on Mars is a relatively recent phenoma).

Re:Life on Mars

[holmstar]

Titan, which is quite a bit smaller than Mars, has an atmosphere 1.5 times as dense as Earths.

Re:This must mean...

[sexconker]

"Also, first post BTW..."

Assuming "BTW" stands for "by the way", the issue is likely the redundancy - "also" and "by the way" are redundant.

Re:Life on Mars

[infinitelink]

Titan is also extremely cold, and has less agitation of its atmosphere; it has protection from Saturn's magnetic field (which it may be holding onto as it does pass through) and is at a much greater distance from the Sun than Ganymede is; the gases compositing the atmospheres of each are also different, which in consideration of their properties may definitely matter: my point is, that neither singly mass, nor density, nor solar distance, nor composition, nor magnetic properties, i.e. any single variable, is responsible for atmospheric density. Mars, however, is both so close to the Sun to be affected by solar winds, and so mass deficient relative to those other factors, that the planet isn't adequate for holding onto a dense atmosphere (of almost any composition): if it were around a dead star, or floating through space away from agitations, etc., then sure, you'd expect it could hold a dense--perhaps frozen (as much of Mars's atmosphere may, in fact, be, and thus on its surface and in its soil)--[r] atmosphere; but considering the variables for holding the kind of gases we'd even be interested in, it's not much worth our time, except perhaps to mine, or for other conditions for experimentation.

The same, unfortunately, applies to Venus--is inadequate to hold onto the kind of atmosphere we'd be interested in, and would even if its role were reversed with Mars (which would also mean it would be too cold). We on Earth have the sweet spot positionally, in mass, gravitationally, in density, and all the other variables you could think of. I'm happy for it too! : )

Re:Life on Mars

[ciroknight]

[Titan is] definitely larger than both Earth or Mercury (thou only by ~1000km on its diameter)

No it isn't [wikipedia.org].