A recent study by NASA has indicated the presence of methane gas on Mars, suggesting microbic life underground. Well, Methane is powerful greenhouse gas on the Earth, but its presence on Mars could be indicator of life that originates from biological processes.

So, if methane is on Mars, there's possibility of life as well, but according to the study, methane on Mars could be coming from changes in rocks.

The presence of Methane on Mars has been indicates by several past studies, but none has indicated regular methane on Mars. NASA's recent study that appeared in the online edition of the journal Science Thursday, states that a team of researchers led by Michael Mumma, a senior planetary scientist at the NASA Goddard Space Flight Center, using three ground-based telescopes, spotted that about 21,000 tons of methane were belched to the Martian atmosphere "during a few months of the late summer of 2003".

According to the researchers, the Methane belch that they spotted on Mars is similar to the Methane coming from decaying life in the sea floor of the waters near Santa Barbara, California.

The researchers say that the microbes in Arctic and other extreme Earth environments don't use oxygen still release methane, and that is the possibility the researchers are nosing about on the other planets.

Study author Michael Mumma of NASA's Goddard Space Flight Center, said, "This raises the probability substantially that life was there or still survives at the present."

Speaking at a news conference telecasted from NASA's Washington, D. C., headquarters, Sushil Atreya, a professor of atmospheric and space science at the University of Michigan at Ann Arbor (who did not contribute to the study), the source of methane spotted on Mars could be "geology, in which case it's the reaction between water and rock, or it's biology, in which case the microbes are producing the methane." He stated that "the discovery of individual methane plumes points to the existence of localized aquifers (water-bearing rock layers) under the surface".

But Mumma stated that proofs are not really enough; it'll be too early to claim that there is life on Mars, because life need far more evidences. According to the study author, most of methane had disappeared from Mars by 2006, which is still a mystery for his team.