This image of a region of Mars called Nili Fossae was released by the European Space Agency on May 6. In 2009 scientists found high concentrations of methane over the area, but they're not sure of its source—it "could be geological or perhaps even biological," according to the ESA. The agency, along with NASA, plans to launch the ExoMars Trace Gas Orbiter in 2016 to investigate further.

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