spacetoday.net: Methane detected in Martian atmosphere

Posted: Tue, Mar 30, 2004, 11:37 AM ET (1637 GMT)
Hubble image of Mars

Planetary scientists have discovered traces of methane gas in the atmosphere of Mars, but are guarded about whether this is evidence of life on the planet. Two separate surveys have detected traces of the gas in the atmosphere: one by European scientists using a spectrometer on the Mars Express spacecraft, and another by a NASA scientist using groundbased instruments. Because methane in the atmosphere is broken down by ultraviolet light over the span of just a few hundred years, the discovery implies that methane continues to be produced. One possible source of methane is emissions by microbes, possibly living beneath the Martian surface, but the methane could have a volcanic origin as well. Scientists said there is not enough information to determine which scenario is more likely to be correct.