astroengine writes "NASA's Mars rover Curiosity has been scouring the thin Martian atmosphere for methane — a potential tracer for the presence of Martian life. However, since the gas also can be produced geologically, any findings promised a meaty debate. That discussion can be shelved, perhaps permanently, new findings from a team of Curiosity scientists shows. The most extensive search yet for methane in Mars' atmosphere has come up empty. 'It's disappointing, of course. We would have liked to get [to Gale Crater] and found lots of methane and measure all the isotopes,' lead researcher Christopher Webster, with NASA's Jet Propulsion Laboratory in Pasadena, Calif., told Discovery News."