Is there life on Jupiter’s moon?

The hunt for alien life just made a pretty big breakthrough.

Unfortunately — or perhaps fortunately — we’re not anticipating flying saucers on the White House lawn anytime soon. Instead, scientists discovered a (relatively) easily-accessible source of hydrogen and oxygen — which together make water, one of the most basic ingredients for life — on one of Jupiter’s moons.

There is already lots and lots of evidence for the existence of both liquid and frozen water in other parts of our solar system. Frozen water is abundant in asteroidsIn 2009, huge amounts of frozen water were found on Earth’s moon. Some scientists suggest that Mars’ surface has been shaped by the flow of liquid water, and NASA’s Curiosity rover found frozen water in soil samples on Mars just this year. And back in 2000, the Galileo probe found evidence of water on Jupiter’s moons Ganymede and Europa — and scientists believe that liquid oceans of water are trapped beneath the the moons’ frozen surfaces.