Methane on Mars == Life?

Evidence pointing to possible alien life on Mars today has been suggested by the recent methane detected in the atmosphere of the Red Planet by the European Mars Express spacecraft and confirmed by Earth-based telespcope observations. Michael Mumma of the NASA Goddard Space Flight Center in Maryland, when asked if the methane was biological in origin, said "I think it is, myself personally." in a report posted on Slashdot. The discovery of past oceans of salty water by one of the two Mars Exploration Rovers recently adds scientific excitement to the confirmed discovery of atmospheric methane raising human hopes of finding life on Mars. Methane exists only brifely in the Mars atmosphere and must be replinished frequently to be sustained with two working theories now before scientists: living microbes or active volcanoes. Methane has a relatively short lifetime on Mars for atmospheric gases, about 300 years or so, scientists believe there must be some process at work to keep replenishing its concentration in the atmosphere.
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