London, Jan 16 (ANI): In the most sensitive measurements yet made of the Martian atmosphere, scientists have determined that methane gas in the environment of the Red Planet is concentrated in three specific regions.
Since methane was first discovered on Mars in 2003, three teams have found signatures of the gas using ground-based telescopes as well as Europe's Mars Express orbiter.
Some observations hinted that the gas was not distributed evenly across the planet, but the source of the methane remained unclear.
Now, according to a report in New Scientist, a team led by Michael Mumma of the Goddard Space Flight Center in Greenbelt, Maryland, has released high-resolution maps of Mars from 2003 that pinpoint three areas just north of the Martian equator that seem to be the source of the gas.
The discovery will likely stoke further debate on the source of the gas, which could be created through geological processes but might be tantalizing evidence of life below the Martian surface.
The team used two telescopes in Hawaii to measure the light emitted by the planet.
By observing Mars through a long, narrow slit, the team built up a high-resolution map of methane as the planet rotated.
"We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tonnes of methane," team member Geronimo Villanueva of the Catholic University of America in Washington, DC, said in a statement.
"The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporised, allowing methane to seep into the Martian air," he added.
One of the three regions is centred on a rift called Nili Fossae, which had until late last year been considered as a possible landing site for NASA's one-tonne rover, the Mars Science Laboratory, which is set to launch in 2011.
The two other hotspots, each some 1000 kilometres away, have different geologies.
One centres on the southeastern region of the volcano Syrtis Major. The other is a flatter, cratered region called Terra Sabae.
"This is the very first evidence of local methane sources," Mumma told New Scientist.
According to Sushil Atreya, a member of the Mars Express team at the University of Michigan, the results are impressive.
"The previous observations, particularly those from Mars Express, gave only a hint of broad areas of possibly large abundances of methane," he told New Scientist. Moreover, the Mars Express results relied on a single strong spectral line of methane, whereas the current data identify at least two lines, which gives more confidence in the presence of methane on Mars," he added. (ANI)