Institute for Advanced Study Astrophysics Seminar

ABSTRACT: For the last six years, the Cassini spacecraft has been in orbit around Saturn, making a wide variety of measurements of the planet, its moons and its rings. Besides yielding such dramatic discoveries as the lakes of liquid hydrocarbons on Titan and the plumes of gas and ice emerging from Enceladus, these data have also provided abundant new information about the diverse range of dynamical phenomena occurring in this complex system. In particular, Saturn's diverse rings provide an unique opportunity to investigate the physical processes operating in astrophysical disks (including galaxies and proto-planetary disks) in great detail and at high resolution.(albeit in different regimes of surface mass densities and velocity dispersions). Indeed, Saturn's dense main rings are found to possess structures on a wide range of scales that are generated by interactions among the various ring particles as well as gravitational perturbations from Saturn's various moons, while the dusty faint rings show evidence for material being perturbed by non-gravitational forces originating from both Saturn's magnetosphere and the Sun. Some rings even appear to contain discrete embedded objects whose orbital motions are being perturbed by their interactions with the rest of the rings.