The Methane of Mars
From Physorg.com, findings from the red planet shows that the amount of methane (CH4) in the Martian atmosphere is not caused by meteorites. So now the thinking is that it is caused by the reaction of rock with water and CO2 or it is biological.
Given the amount of CO2 in Mars’ atmosphere, I’m leaning toward the geologic origin. But one can dream of Martian Microbes.
