We found an ancient lake on Mars — a sign the planet may have once been habitable

Earlier this week, the scientists running NASA's Curiosity rover announced the mission's latest finding: evidence of an ancient Martian lake that appears to have formed over the course of millions of years and has since dried up. Naturally, this has a lot of people asking the obvious question: Was Mars once home to alien life? This is a difficult question, and one that scientists still don't have a full answer to. But by collecting more and more data with Curiosity and other probes, they're getting a better idea of what Mars looked like billions of years ago. http://www.vox.com/2014/12/11/7376103/mars-curiosity-lake Here's what we know — and how the new finding changes things.READ MORE AND SEE PHOTOS LINK-