Event DetailsEvent Dates: Wednesday, August 30, 2017 - 4:00pmSeminar Location: Duane Physics Room G1B20Speaker Name(s): Sascha KempfSpeaker Affiliation(s): University of Colorado, Boulder Seminar Type/SubjectScientific Seminar Type: Physics Department ColloquiumEvent Details & Abstract: When Galileo Galilei discovered Saturn’s rings 450 years ago he didn’t even know that he had observed rings. It was Christiaan Huygens who proposed that Saturn is surrounded by a thin solid ring - made of metal. Earth-based spectroscopic observations in 1970 revealed that the rings in fact consist of 95% clean water ice, but the nature of the other 5% of embedded material, which gives the rings their unique reddish tint, is still unknown. It is, however, this little amount of unknown material that will bring us closer to understanding the rings’ origin and provide valuable information about the formation of the Saturnian system as a whole. After almost 20 years in space, NASA's Cassini spacecraft has begun the final chapter of its remarkable story of exploration: its Grand Finale. Before the spacecraft plunges into Saturn’s atmosphere Cassini is undertaking a daring set of orbits that is, in many ways, a whole new mission. Starting in late April this year Cassini is performing weekly dives between the planet and the inner rim of Saturn’s rings. No other mission has ever explored this region that has been considered until a few years ago to be inaccessible for space probes. Those unique orbits allowed the Cosmic Dust Analyzer (CDA) on Cassini for the very first time to collect material originating from the main rings itself and to identify their composition. In my talk I will report about the exciting findings by CDA during Cassini’s swan song.