Mike Mumma gave the Goddard Science Colloquium last Friday and described recent work detecting methane on Mars. This has a rocky history as there have been several claims over the last 20-30 years which have not been confirmed. The significance of a detection is that most methane on Earth is biotic. Methane on Mars could be abiotic but that would imply that the planet is geologically active which is not thought true at the moment. Mumma emphasized the importance of simultaneous imaging because ice clouds in the Martian atmosphere will reduce the column observed hence change the calculated abundance. His team have been performing long-slit near-IR spectroscopy using IRTF and Gemini South and they have clear detections of methane which is spatially variable. They are now looking for correlations with ground features, temperature etc. Once the geographic sources of methane have been identified then other tests can be performed, ideally involving in situ measurements of 12C/13C ratios which are diagnostics of biotic origins.
Keywords: astrobiology, Mars
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