NASA Podcasts

The Mystery of Martian Methane
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Michael J. Mumma: My name is Michael Mumma. I work at Goddard Space 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'd 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.

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