> Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA Explanation: What’s that behind Titan? It’s another of Saturn’s moons: Tethys. The robotic Cassini spacecraft orbiting Saturn captured the heavily cratered Tethys slipping behind Saturn’s atmosphere-shrouded Titan late last year. The largest crater on Tethys, Odysseus, is easily visible on the distant moon. Titan shows not…