NASA Rover Fails to Turn Up Methane On Mars 106
The Washington Post is one of many sources to report the possibly disappointing news that NASA's Curiosity rover has failed to find any methane on Mars. "[NASA planetary scientist Michael] Mumma had high hopes for a positive result because he and his colleagues believe they have detected methane on Mars remotely, from telescopes on Earth that can discern the chemical nature of Mars’s atmosphere. A European orbiter around Mars also spotted methane. But the methane has proved ephemeral — now you see it, now you don’t. Mumma said he and his colleagues are reviewing their work to see if there is some error in the mix. Perhaps the methane simply disappears quickly on Mars, through some unknown chemical process. 'It’s possible that we don’t understand something that’s going on in the Martian atmosphere,' said Michael Meyer, lead scientist for NASA’s Mars Exploration Program.'"
Re:Which to trust? (Score:5, Informative)
On the one hand, we've had a lot of experience with spectroscopy, and on the other we have a rover actually there.
Depending on exactly where in the atmosphere the light used for the spectroscopy data is coming from, they might both be accurate: If you were working by telescope, Earth should show plenty of ozone; but if your ground-level sampling station is turning up any nontrival amount, that means that something is rather wrong...
Were that the case, I have no doubt that all sorts of vexing questions about how such a methane distribution could come to be would come up; but atmospheres do vary by location.