Reading the Record of Ancient Impacts
Peter Goldreich, Institute for Advanced Study
Abstract:
Debris from asteroids and comets continually bombards the Earth. Big impacts launch ejecta on trajectories that carry them thousands of kilometers from the impact site. These are recorded in discrete layers of submillimeter
size spherules in sea floor sediments. Larger, aerodynamically shaped,
objects are found on land. I will describe the physical processes that occur
in energetic impacts with emphasis on the evolution of the fireball and
determination of the range and size of the ejecta.