Jupiter's moon Europa is covered in a thick layer of ice, but it has a turbulent ocean that lies beneath. Today astronomers announced that new observations show this water is erupting in massive plumes like water volcanoes. It's a discovery that could have serious implications for Europa's potential to harbor life.
Astronomers have never before seen any geological activity on the surface of Europa. They'd speculated that it had an active subsurface ocean (which was confirmed independently by magnetometer measurements) and they knew its scarred, icy surface known as chaos terrains was the result of turbulent waters near the lower latitudes. Still, the moon's active ocean was known only by inference. Nor had they observed any kind of noteworthy weather; the moon has an incredibly thin atmosphere comprised of trace amounts of oxygen.