Methane in Mars, possibility of life

Methane, a potential sign of primitive life, has been found in meteorites from Mars, adding weight to the idea that life could live off methane on the Red Planet, researchers say. This discovery is not evidence that life exists, or has ever existed, on Mars, the researchers cautioned. Still, methane "is an ingredient that could potentially support microbial activity in the Red Planet," study lead author Nigel Blamey, a geochemist at Brock University in St. Catharines,  Much of the methane in Earth's atmosphere is produced by life, such as cattle
digesting food. However, there are ways to produce methane without life, such as volcanic activity.
To shed light on the nature of the methane on Mars, Blamey and his colleagues analyzed rocks blasted off Mars by cosmic impacts that subsequently crash-landed on Earth as meteorites. About 220 pounds of Martian meteorites have been found on Earth. The scientists focused on six meteorites from Mars that serve as examples of volcanic rocks there, collecting samples about one-quarter of a gram from each — a little bigger than a 1-carat diamond. All the samples were taken from the interiors of the meteorites, to avoid terrestrial contamination.