[X] My Assistant

[Stu]

Interesting...

http://www.spaceref.com/news/viewpr.html?pid=27336

[silylene]

From Science Daily: http://www.sciencedaily.com/releases/2009/...90115164621.htm

"We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane," said co-author Geronimo Villanueva of the Catholic University of America in Washington. "The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporized, allowing methane to seep into the Martian air."

I do wonder if the words ' plumes' and 'were emitted' bias the assumption of origin. I really do hope that the authors do find out in time that their words were chosen wisely!

Of course if all that methane came from one or several vents during the warm season, that would be a HUGE amount !

But let me analyze it another way. From the maps of Mars with methane levels, let's assume that high signals for methane were found conservatively over about 10% of the Martian surface (it actually looks more like about 20+%).

Assuming that methane is formed on about 10% of the Martian surface, and over a 90 day warm period, then the generation level is 13g/km^2/day, or about 0.000013 g / m^2/day. I do think this is not too much for a photochemical generation source. So I do wonder how a photochemical mechanism was dismissed as a source. I am very interested in reading this paper!

Calculation:
Mars surface area = 144 798 500 km²

19,000*2000/2.2 / (144798500*0.10) / 90 * 1000g = 13 g/km^2/day

13 /1000/1000 = 0.000013 g / m^2/day

[sci44]

Assuming that methane is formed on about 10% of the Martian surface, and over a 90 day warm period, then the generation level is 13g/km^2/day, or about 0.000013 g / m^2/day. I do think this is not too much for a photochemical generation source. So I do wonder how a photochemical mechanism was dismissed as a source. I am very interested in reading this paper!

Thats interesting - only 13g CH4/km2/day (1.3g/km2/day globally) - its not much to account for. Another possibility I havent seen mentioned yet is the formation of CH4 by Electrical activity within Dust Storms. There you have the energy input/heat plus the possible presence of catalysts in the dust, acting on atmospheric CO2 and traces of water:

Directly: CO2 + 2H2O + Energy -> (With catalyst/intermediate reaction) CH4 + 2O2

Or acting with any Olivine within the dust (see Juramike's post here too):
Indirectly: (Fe,Mg)2SiO4 + 4H2O + CO2 --> Mg3SiO5(OH4) + Fe3O4 + CH4

My question being: could lightning/electrostatic energy be another source of energy for this reaction - apart from volcanic heat/sunlight?

Again, just a bit of speculation, YMMV. Feel free to laugh me out of court..

[AndyG]

I'm having a hard time getting my head around the seasonality of a subsurface production. Assuming a regular generation and subsequent build-up of subsurface (abiotic) methane, vented when ice sublimes: how does new ice form to plug any "vents" year-on-year when that liquid is being lost over geological time?

That alone suggests a greater likelihood for photochemical production (or sci44's electrically-aided dust-storms - which could be easily tested by tying in observations to global dust-storm events?)

Andy