Latest Martian mystery is a real gas

Something is happening beneath the surface of Mars that causes substantial amounts of methane gas to burst out regularly, a discovery that NASA scientists say represents the strongest indication so far that life might exist, or once existed, on the planet.

The methane is released into the atmosphere in specific areas and at regular times, they found, in a pattern that would be consistent with the gas being a byproduct of biological activity beneath the planet's parched surface.

Principal investigator Michael Mumma, of NASA's Goddard Space Flight Center, said the detection does not mean that life definitely exists on Mars, because the gas can be produced by subsurface geological or chemical processes as well. Nevertheless, "we believe this definitely increases the prospects for finding life on Mars," said Mumma, whose findings were published online by Science Express. "No other discovery has done as much to increase the chances of finding life."

The scientists detected plumes of methane during two Martian summers, when the planet's large formations of subsurface ice might melt and release the gas. Most of the methane in Earth's atmosphere is produced by bacteria in living creatures large and small. Even if it turns out that the Martian methane is the result of non-biological processes - a far less dramatic prospect - that would nonetheless reshape thinking about the planet, which scientists thought to be geologically dead and chemically unlikely to produce much of the gas.

Scientists have been working to confirm the presence of methane on Mars since it was preliminarily detected in 2003, first by Mumma and then by scientists working with the European Space Agency. The new findings confirm that discovery and describe intense, recurring, but relatively brief releases that are consistent with either biological or active geological origins.

The new data were gleaned by NASA's Infrared Telescope Facility atop Mauna Kea, Hawaii, and another telescope in Chile.