ENCELADUS, AN ERUPTING OCEAN WORLD

The geyser moon Enceladus shows off its fractured folds and ridges in a mosaic of Cassini images taken from March 9 to July 14, 2005. Credit: NASA/JPL/Space Science Institute

Enceladus may be a tiny moon, but it has a pretty big reputation among scientists looking for life beyond Earth.

Spotted by Cassini in 2005, dozens of saltwater geysers erupt from fissures in the moon’s south pole. Some of the erupting material falls back to the surface like a dusting of snow, but the rest escapes into space, where it’s responsible for crafting Saturn’s thin, far-flung E ring.

The jets are fueled by a global sea beneath Enceladus’s icy crust. When Cassini flew through and sampled the plumes, it discovered that the alien water contains all the ingredients we believe are necessary for life to exist. Chemicals in the geysers also offer hints that hydrothermal vents are active on the ocean floor. What’s more, the hidden ocean has potentially existed for billions of years—more than enough time for life to evolve.