************************************************************************* Departments of Mathematical Sciences and Mathematics The Johns Hopkins University JOINT SEMINAR ************************************************************************* Professor Thomas C. Hales March 30, 2000 Department of Mathematics 304 Whitehead Hall University of Michigan NO PRESEMINAR Refreshments: 3:30 p.m. Seminar: 4:00 p.m. ************************************************************************* THE PROOF OF THE KEPLER CONJECTURE ************************************************************************* ABSTRACT Over 400 years ago, Sir Walter Raleigh asked his mathematical assistant to find formulas for the number of cannonballs in regularly stacked piles. These investigations aroused the curiosity of the great astronomer, Johannes Kepler, and led to a problem that has gone centuries without a solution: Why is the familiar cannonball stack the most efficient arrangement possible? This talk will describe the history of this and some related problems in geometry. (The first special case of the Kepler conjecture was established by Gauss in 1831.) Various bounds on the density of a sphere packing have been obtained in the 20th century. This talk will describe a recent computer-assisted proof of the Kepler conjecture. *************************************************************************