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Running rings around Saturn


Feb. 13, 2014, 4 p.m. - 5 p.m.
Geology 3656

Presented By:
Josh Colwell
University of Central Florida

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The Cassini spacecraft entered Saturn orbit on June 30, 2004. Now in its ninth year orbiting Saturn, Cassini has completed more than 180 orbits of the ringed planet. Although Saturn’s rings are one of the most prominent and dramatic features of the solar system, their origin and age remain uncertain. Clues to the evolution of the rings exist in the complex structure and interactions of the ring particles. The Ultraviolet Imaging Spectrograph (UVIS) on Cassini has observed more than 100 stellar occultations of the rings. These measurements provide the highest spatial resolution data of the structure of the rings, but each occultation is only a one-dimensional cut across the rings. However, the multitude of observations at different times and different viewing geometries enables us to reconstruct the three-dimensional structure of the rings by treating the occultations like a medical Computed Tomography (CT) scan. This has revealed details about the clumping of the ring particles into so-called self-gravity wakes which are the result of the competing forces of Saturn’s tides which inhibit accretion and the gravitational attraction between the ring particles. In addition, occultations have revealed transient or localized structures that are mere meters across. Some of these may be the signature of accretion taking place within Saturn’s rings. I will provide an overview of the ring system and the observations of Saturn’s rings made with UVIS and discuss their implications for understanding the evolution of the ring system.