(Photo : Getty Images)
Scientists are cautiously optimistic about their latest discovery in the quest to determine if life exists or has ever existed on Mars. After analyzing the interior of Martian meteorites, they've discovered a gas that in some cases is tied directly to organic life: methane.
The research was published this week in the journal Nature Communications, and is the latest attempt at determining whether methane, which can support microbial life or be released as a byproduct of living organisms, is actually present on Mars. A previous mission by NASA's Curiosity Rover picked up traces of methane during sampling of the Red Planet, but scientists are not in agreement as to whether the gas originated on Mars or was contaminated by the rover itself.
"The putative occurrence of methane in the Martian atmosphere has had a major influence on the exploration of Mars, especially by the implication of active biology," the study authors wrote. "The occurrence has not been borne out by measurements of atmosphere by the MSL rover Curiosity but, as on Earth, methane on Mars is most likely in the subsurface of the crust."
So they examined the contents of six Martian meteorites and were surprised to find strong methane signals within. All six of the meteorites contained methane, along with carbon dioxide, hydrogen, nitrogen and small amounts of argon and oxygen.
"The availability of methane and hydrogen is critical to the potential of the Martian crust as a habitat for microbial life," the study authors wrote. "The hostile Martian surface is probably less habitable than the subsurface, and several scenarios have been proposed for deep Martian life."
Scientists are exercising caution with this latest discovery. Methane can also be produced by volcanic activity, so its presence does not guarantee life on the planet. But hope springs eternal among geochemists involved in the research.
"We have not found life, but we have found methane that could potentially support microbes in the subsurface," says lead author Nigel Blamey of the Brock University in St. Catharines, Ontario.
Scientists hope to examine more Martian meteorites, in order to better understand the planet's atmosphere and composition. But if microbes can live off of methane deep within Earth, perhaps similar conditions exist on Mars as well.
"The evidence presented here indicates that a methane-bearing subsurface habitat is similarly available on Mars," the authors say. "Whether or not the habitat has been occupied remains to be determined."