Imperial College, London: Life on Mars theory boosted by new methane study
Scientists have ruled out the possibility that methane is delivered to Mars by meteorites, raising fresh hopes that the gas might be generated by life on the red planet, in research published tomorrow (Wednesday 9 December 2009) in Earth and Planetary Science Letters.
Methane has a short lifetime of just a few hundred years on Mars because it is constantly being depleted by a chemical reaction in the planet's atmosphere, caused by sunlight. Scientists analysing data from telescopic observations and unmanned space missions have discovered that methane on Mars is being constantly replenished by an unknown source and they are keen to uncover how the levels of methane are being topped up.
Scientists at Imperial College estimate 10kg of methane a year is a result of meteorites. To maintain atmospheric levels, you need 100 to 300 tonnes a year. 10kg is 0.01 tonnes, so the rest has to come from somewhere else. Whatever is producing the methane is making a lot of it on a regular basis.
The BBC also wrote an article on this: Mars methane 'not from meteors'.