Planetary scientists at NASA’s Goddard Flight Center claim to have identified hotspots of methane gas emission, extremely localized plumes whose concentration fades quickly in time. An atmosphere-wide distribution that’s stable in time would indicate a balance between geological sources and destruction by sunlight. Localized sources, however, suggest much more active sources.
What’s the best source of methane most people know about? Cows. That’s unlikely on Mars. But backing off a level, the important factor is LIFE. NASA team leader Michael Mumma puts forward the idea that subterranean bacteria could be producing the noxious fumes, which periodically percolate to the surface in short lived bursts. But it could also be a geological source deep below the surface. The CH4 was identified spectroscopically, analyzing the exact wavelengths of the light emitted from certain regions over time. It’s exactly the same strategy the astronomers of old used, “just looking at what color things are”, but since we worked out (some) quantum mechanics the same light can tell us so much more. Unfortunately, it can’t make the crucial distinction between life or rock-based gas.
But if we can just get a bit closer we can find out.