update about methane on mars
This is an article from BBC news regarding methane detected on Mars. They report three discrete “plumes†and seasonal variation, and speculate on geological or biological origins.
methane bbc
(http://news.bbc.co.uk/2/hi/science/nature/7829315.stm)
A quote:
“The team used a technique called infrared spectroscopy at three different Earth-based telescopes to monitor about 90% of the planet's surface for seven years (equivalent to three Martian years). They identified "plumes" of methane on Mars during 2003; at one point in their study, the primary plume of methane contained an estimated 19,000 tonnes of the gas.â€