 NASA's Cassini spacecraft has sniffed out something pretty exciting coming from Saturn's moon Enceladus. Turns out hydrogen molecules are spewing out from this icy snowball. And while that might not seem super interesting, it's a huge indicator that Enceladus could house alien life. Enceladus is already a big favorite in the search for life elsewhere in our solar system, since the moon is thought to harbor a vast liquid ocean underneath its surface. This ocean water periodically erupts from Enceladus in the form of geysers or plumes. In October of 2015, Cassini did a deep dive into one of these plumes, coming within 30 miles of the moon's surface. And when it did, it got a whiff of hydrogen molecules. The presence of hydrogen in the water is big, since it clenches this idea that there are underwater hot springs on Enceladus. It's known as hydrothermal activity, and it happens when the chilly ocean mingles with the piping hot rock on the seafloor. The same thing happens on Earth, too. They're called hydrothermal vents, and they form underwater along ridges or cracks in the crust. The heated mix of water and rock leads to chemical reactions that produce all kinds of hot material that jet upward. These reactions can create a breeding ground for microbes, and many think that some of the first forms of life popped up around these kinds of vents. Hydrogen is particularly enticing, too, since this molecule is like candy for some deep sea microbes. On Earth, some organisms around hydrothermal vents munch on hydrogen, converting it to energy needed to live. So if hydrogen molecules are present on Enceladus, maybe similar kinds of microbes are also munching on it. Which could mean… well, before we get ahead of ourselves, this finding does not actually mean we've found life on Enceladus. So sorry, no aliens just yet. Plus, there are a few signs that indicate maybe life isn't there. Cassini detected quite a bit of hydrogen, more than what would be expected if microbes were eating it to survive. So it's possible that there's no one around to eat this stuff. Or maybe the microbes are there, but something is keeping the population from getting too big. It's possible there's an element missing that these microbes need to really thrive. Either way, this is a huge finding from Cassini, and it ironically comes at a time when the spacecraft is about to meet its end. In a couple weeks, Cassini is about to put itself into its final few orbits around Saturn. These will take the spacecraft closer to the planet than ever before. But once those orbits are done, Cassini will then plunge into Saturn and break apart. But these latest findings just mean that we need to send something else to Enceladus. Cassini wasn't really designed to make the kind of measurements it has regarding the moon. But now that we know all this info, perhaps it's time to send a probe to Enceladus that's designed to sniff out life.