The Curiosity rover has discovered evidence of an ancient freshwater lake on Mars that was brimming with the key chemicals necessary to support microbial life, and its findings suggest that it could have held that life more recently than we thought—and possibly for millions of years before that. "Quite honestly it just looks very Earth-like," the Curiosity's lead scientist said, according to Space.com. The lake, located in the Gale Crater, would have been about 30 miles long and 3 miles wide.
The lake's mudstones—which form in calm, still water—contain traces of sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon, meaning it could have supported chemolithoautotrophs, a kind of microbial that obtains energy by breaking down rock minerals. The lake was revealed today amidst a barrage of papers on the Rover's progress. National Geographic breaks down some of the other key take-aways, including one that's less promising for Martian life hunters: Curiosity's first radiation measurements indicate levels that would be fatal, within a few million years, to anything within several meters of the surface. Though the researchers did note that some classes of bacteria might have been able to survive through long periods of hibernation. (Read more Mars stories.)