"Comets, unseen planets, and the outer fringes of the solar system"
Comets have inspired awe since prehistoric times, but the modern study of comets only began with Halley's successful prediction of the return of what is now called Halley's comet. Even today there are only a few thousand comets with well-determined orbits. Nevertheless, the analysis of this limited sample yields a compelling model for the formation, evolution and present distribution of comets. This model implies that the primary source of comets is the Oort cloud, containing over 100 billion comets at 5,000 to 50,000 times the Earth-Sun distance. I will review our current understanding of the formation of the Oort cloud, and what comets can tell us about possible undiscovered planets beyond Neptune. Finally, I'll describe some of the puzzles arising from the recent discovery of an interstellar asteroid/comet, ʻOumuamua.
About the speaker
Scott Tremaine received his Ph.D. in physics from Princeton. He has held faculty positions at MIT, the University of Toronto, and Princeton. He was the first Director of the Canadian Institute for Theoretical Astrophysics from 1985 to 1996, and chair of the Department of Astrophysical Sciences at Princeton from 1998 to 2006. He is currently the Richard Black Professor at the Institute for Advanced Study in Princeton. He is a Fellow of the Royal Societies of London and of Canada and a member of the U.S. National Academy of Sciences. His research is focused on the dynamics of astrophysical systems, including planet formation and evolution, black holes, star clusters, and galaxies.
Details on Scott's research can be found here.