NASA says methane and water vapor on Mars could point to the presence of
living organisms on the Red Planet.

WASHINGTON, DC, UNITED STATES (JANUARY 15, 2009) NASA -
New observations of the atmosphere on Mars show fairly large
amounts of methane along with water vapor in the summertime -- the strongest
suggestion yet that living organisms might be producing the gas, NASA said on
Thursday (January 15).

NASA scientists stressed that there was no direct evidence that
anything living produced the methane, but that the possibility was being
considered.
"Methane can be a waste product from microbes that are
methane-generating, but methane can also be a food for microbes that are
methane consumers, so, in either way, this is exciting because we have
evidence that we need to think about in terms of the possibilities of life on
Mars," said Lisa Pratt, Professor of Geological Science at Indiana
University, at a NASA briefing.

NASA said the methane could be produced by volcanic activity, could be
made by live microbes, or could be left over from long-extinct life.
"There are two possibilities again. Either it's geology -- in
which case it's the reaction between water and rock that's producing the
methane, or it's biology -- in which case the microbes are producing the
methane," said Sushil Atreya, Professor of Atmospheric and Space Science
at University Of Michigan.

On Earth, methane is known as swamp gas and made by decaying plants or
found in the burps, belches and other emissions of animals from termites to
cattle and people. It is made up of carbon and hydrogen.
The methane appears to have been produced in plumes from certain areas
on Mars as temperatures warmed, the scientists said.
Water exists on Mars, and robot rovers have sampled ice from the
surface. Scientists are eager to know how much more water is below the surface
and whether it could support life now or in the past.