It has long been speculated that the existence of methane on other planets and moons could be a sign that life may be present now or have been present in the past. This is because the methane in our atmosphere comes primarily from life functions like the digestion of cows or termites. So scientists are very interested in Saturn’s moon Titan because of the methane in its atmosphere and the probable methane seas. But yesterday we got some very interesting news from Mars, Curiosity Rover Detects Spikes of Methane at Mars.
What the little rover is seeing is methane levels shooting way up and then coming way back down — below even the average global concentration. Sushil Atreya of the Curiosity team said it “tells us there must be some relatively localized source.” Even if it is of biological origin, it could be an ancient source of the gas, which is slowly being released or cycled through the environment. Or it could be of totally non-biological original through a source “such as interaction of water and rock.” So we want to be cautious here, because the news is interesting but doesn’t necessarily mean anything.
Nicholas Heavens at The Planetary Society had a few choice words of caution even before he found out what the discovery was, Like A Bad Penny: Methane on Mars. I think he is far too cynical, but he does provide a nice overview of the methane-related discoveries on Mars. They start with the measurement of the methane concentration in the Mars atmosphere that is half of what it is here on earth. But that is less impressive than it sounds because the Mars atmosphere is so thin and concentrations are reported as (very very small) percentages. Heavens concludes, “Mars had some methane, but not very much of it.” Like I said: cynical!
He went on to discuss some of the potential problems there were with the initial measurements of methane. The main one was that there was a fairly high level of variability in them. Again, he wrote this before seeing what the new research showed. But now that we do know, it at least partially explains the methane variability. But Heavens’ main concern seems to be that people go hog-wild with the little information we have. Caution is good advice. It makes me think of a sequence from Cosmos about the same thing regarding Venus, “Observation: you couldn’t see a thing. Conclusion: dinosaurs.”
The main thing to remember here is that as exciting as this all is, it is unlikely that any of it indicates that life exists on Mars right now. But it is more data that suggests that Mars did indeed have life on it at one time. And it was a high tech civilization that created canals to move water from the poles! And they flew around on jetpacks like in The Jetsons! And they had domesticated dinosaurs that children rode on at the fair! Stop, stop, stop! I got carried away there. None of sentences the that end with an exclamation mark is true. But the next one is:
And that is enough to be very very excited. And I doubt that Nicholas Heavens would disagree.