Titan looms behind Saturn’s brilliant rings and the small, battered moon Epimetheus. Saturn’s largest moon by far, Titan has mystified astronomers for more than 300 years. When the Voyager 1 probe flew by in 1980, scientists were disappointed to see nothing but a featureless orb cloaked in opaque smog. Scientists would have to wait until the Cassini mission to learn what lay beneath Titan’s thick atmosphere. “It’s been like a Jules Verne adventure come true,” Porco says. “It’s another milestone in coming to understand our cosmic neighborhood.”