Ring Runner
The Cassini mission to Saturn will be doing some ring science this week. On Oct. 10, Cassini's instruments will observe a stellar occultation of the red giant star Lambda Velorum. Stellar occultations, when the rings appear to pass in front of a star from Cassini's perspective, can be used to probe the rings' fine-scale structure. On Oct. 12 and 13, Cassini's cameras will watch for "propellers" in the outer A ring. Propellers are voids in the ring created by the gravity of larger ring particles, ones that are about 300 - 3300 feet (100 - 1000 meters) wide.
