One of the most provocative questions about Mars today is what is causing periodic spikes in the amount of methane in the planet's atmosphere. On Earth, methane is strongly tied to biological activities, raising the prospect that colonies of methane-emitting microbes might be living on Mars. Another option is that the gas stems from geological activities, though so far attempts to match the methane spikes with the seasons have not panned out. NASA scientists have another idea – meteor showers, saying there is a correlation between when the methane plumes appear and Mars’ transit through a region of space littered by remnants of a comet, the source material for meteor showers. http://www.space.com/32342-did-mars-methane-come-from-comets.html
