Does the presence of methane mean there are living organisms on Mars?
Most of the methane in Earth’s atmosphere has a biological origin (decomposition of plants in bogs, emissions from paddy fields, emissions from termites and cows and sheep, burning of fossil fuels etc.), so discovery of methane on Mars quickens the pulse of scientists who are looking for signs of life on the Red Planet. But the methane there could also have been created by a geological process known as serpentinisation which requires both heat and liquid water. Where there is water there is possibility of life. So discovery of methane on Mars opens up various possibilities and is therefore a very important development.