Wednesday, March 29, 2006
More Glory: Propeller-Shaped Structures in Saturn's RingsScientists have found evidence for small moonlets within Saturn's rings. The moons, estimated to be about 300 feet in diameter, are as yet unseen, but they produce strange propeller-shaped disturbances in the ring matrix. First estimates suggest there could be at least ten million of these bodies in the rings. If a moon is big enough, like Pan here (below) its gravity is ample enough to clear out a path in the ring system. The Encke Gap was first observed on Earth in the 1830's. The moon was discovered a century and a half later. In fact, scientists first saw the moon while examining nine-year old Voyager images in 1990. You can just see the "scalloped" edges on the edge of the gap. In the bottom image, note the dark "waves" in the ring.