Tethys, one of Saturn’s larger icy moons, vaguely resembles an eyeball staring off into space in this view from NASA’s Cassini spacecraft. The resemblance is due to the enormous crater, Odysseus, and ...

Although Tethys and Janus both orbit Saturn and are both made of more or less the same materials, they are very different worlds. Their contrasts are related, in large part, to their sizes. Tethys ...