APPLIED MATHEMATICS SEMINAR AT THE UNIVERSITY OF SYDNEY Speaker: Dr Henrik Latter, University of Cambridge Title: Fine-scale structure of Saturn’s rings DATE: Wednesday, March 28 TIME: 2:00pm LOCATION: University of Sydney, Eastern Avenue Lecture Theatre (Level 1) Abstract: The rings of Saturn are composed of trillions of icy boulders ranging in size from a few centimetres to a few metres. These particles undergo, on average, several very gentle collisions per orbit. In fact, their average impact velocity is barely 2 mm/s! But these seemingly innocuous interactions, when allied with gravity, can have considerable collective effects. Over relatively short time-scales they sculpt the disk into irregular radial patterns. This talk presents an introduction to the physics of planetary rings and concentrates on the theory of fine-scale structure formation. In particular, emphasis is placed on the difficult modelling issues thrown up by a "gas" of infrequently colliding inelastic particles. We find that a planetary ring is in a unique regime which hydrodynamical models cannot adequately capture. http://www.maths.usyd.edu.au/u/AppliedSeminar ------------------------------------------------------------------------