Plumes of Enceladus (2009)
Enceladus is a mid-sized satellite of Saturn, about 500 km across, known since 1789.
In 2005, the Cassini spacecraft discovered that this relatively small world is,
surprisingly, geologically active. Geyser-like jets of water were seen spewing from
the moon's south-polar surface ices, vented by a process called cyrovolcanism ('cold
volcanism'). Another satellite, Mimas, is seen on Saturn's ring plane.
