They’re known as cryovolcanoes, and though scientists don’t have cast-iron proof that volcanoes spouting ice from a sub-zero caldera exist on Enceladus, there is strong evidence for it. The flyover by Cassini two years ago revealed jets spurting from four cracks along the moon’s surface, named Alexandria, Cairo, Baghdad and Damascus. The eruptions were so high that they could easily be seen in profile from space.
Volcanoes found on Earth and also Jupiter’s moon Io spout silicate lava heated by the pressure beneath the crust. Ice volcanoes work in a similar way: scientists believe that subterranean geological activity on Enceladus warms the freezing surface into a slush of water, ice and organic compounds, which is then ejected by ice sheets grinding up against one another. Enceladus has an elliptical orbit similar to our moon, so as Saturn’s gravity pulls unevenly at Enceladus it creates a bulge that generates the friction and heat necessary to cause this previously unheard-of phenomenon.