Clouds of Methane on Mars

Via FoxNews -

NASA and Science magazine announced Thursday that large amounts of methane have been found on the Red Planet, which could be a sign of biological activity.

Nearly 21,000 tons (19,000 metric tons) of methane were released all at once during the late summer of 2003, according to a study published Thursday in the online edition of Science.

"This raises the probability substantially that life was there or still survives at the present," study author Michael Mumma of NASA's Goddard Space Flight Center told The Associated Press. "We think the probability is much higher now based on this evidence."

By 2006, most of the methane had disappeared from the Martian atmosphere, adding to the mystery of the gas, Mumma wrote.

On Earth, methane comes mainly from belching animals such as cows and rotting organic matter such as dead leaves. But it's also pumped out by volcanoes.

"The most obvious source of methane is organisms," planetary scientist Colin Pillinger told London's Sun tabloid. "So if you find methane in an atmosphere, you can suspect there is life. It's not proof, but it makes it worth a much closer look."

The catch is that it breaks down quickly in the atmosphere due to reactions with sunlight, and there haven't been any active volcanoes on Mars for millions of years.

So it could be that the large amounts of methane spotted floating over Mars were created by microbes buried under the soil.

Or it could just be the result of some little-understood geological process.