European scientists recently announced that they had discovered the presence of methane in the atmosphere of Mars using the Mars Express spacecraft. They’ve had a chance to perform further research on the data now, and produced a map of methane concentrations around the planet. This map surprisingly overlaps a similar map of Mars that shows where its water is located. It could be that geothermal processes are feeding the water table, and venting out methane at the same time. A more exciting possibility is that bacterial life survives wherever there’s water, and it’s producing methane as a byproduct.