Martian volcano latest link to possible life.

• Position: The Red Planet

The slopes of a giant Martian volcano, once covered in glacial ice, may have been home to one of the most recent habitable environments yet found on the Red Planet, according to research led by a geologist from Brown University, Providence, R.I.

Nearly twice as tall as Mt. Everest, Arsia Mons is the third tallest volcano on Mars and one of the largest mountains in the solar system. This analysis of the landforms surrounding it shows that eruptions along the volcano's northwest flank occurred at the same time that a glacier covered the region around 210,000,000 years ago.

The heat from those eruptions would have melted massive amounts of ice to create englacial lakes--bodies of water that form within glaciers like liquid bubbles in a half-frozen ice cube. The ice-covered lakes of Arsia Mons would have held hundreds of cubic kilometers of meltwater, according to calculations by Kat Scanlon, a graduate student who led the work--and, where there is water, there is the possibility of a habitable environment. "This is interesting because it's a way to get a lot of liquid water very recently on Mars," Scanlon surmises.

While 210,000,000 years ago might not sound terribly recent, the Arsia Mons site is much younger than the habitable environments turned up by Curiosity and other Mars rovers. Those sites are all likely...