After NASA's announcement last week, Enceladus is the icy moon on everyone's mind -- not that are are many others (sorry, Europa). According to the agency, molecular hydrogen has been found in Enceladus' subterranean ocean, which bolsters the idea that the icy moon could host extraterrestrial microbes. Despite Enceladus' frigid exterior, this ocean is thought to be extremely warm at the bottom -- roughly 90C. So if you're an astrobiologist or tinfoil hat believer like me, this is very exciting because, well, aliens. Obviously.