Flight Center for the National Aeronautics and Space Administration in
Greenbelt, MD. Our team has discovered methane on Mars.
The surprising thing about methane on Mars is that--first, that we
detect it meaning it's recently generated. But in addition, we find
that it's being released from several discrete vents--or sites--on the
planet's surface in either mid-summer in the northern hemisphere or
early spring in the southern hemisphere on Mars, and yet at a later
season, we see essentially no methane.
The big question is, "What is the origin of this methane now being
released?" The two principal areas are first, by analogy with the
earth, it could be released and produced initially--primarily--by
biology. This would be microbial activity acting on certain chemicals
below the surface and then producing methane as a byproduct.
But of course, we can't state with certitude that it is biologically
produced, and so we also consider geochemical mechanisms in which
carbon dioxide is actually combining with water and producing methane
under very high temperatures and pressures--and that methane can then
be released into the atmosphere separately.
One of the most important consequences of our discoveries is that
we've identified certain "signposts" on Mars that basically are like
little flags that say, "Come here, here I am." NASA has several
missions along these lines; one is called the Mars Science Laboratory.
One of the key objectives is to understand whether life ever arose on
Mars by sampling the material on the surface and then evaluating that
in terms of its origins. You can then appreciate that if you go to
this right location, you may in fact be able to identify whether
biology was at work, or geochemistry.