Three methane plumes first spotted on Mars during the summer of 2003 may be signs of hidden volcanic vents or microbes located under the planet's surface. Scientists are still trying to determine if the methane (natural gas) is being produced due to the way rock and ice interacts or it is being produced by microscopic life forms.
A team of scientists used three telescopes to analyze the atmosphere on the Red Planet between 1999 and 2006. The search is now being expanded to search for "biogenic" trace gases that would be associated with the presence of microbes.
About 10 percent of methane discovered on Earth results from geologic processes, and the other 90 percent is a byproduct of biological events. Astrobiologist Lisa Pratt of Indiana University in Bloomington, who spoke at the NASA briefing on this study, had this to say: "We have evidence here that we need to think about the possibilities in terms of life on Mars."