Institute for Advanced Study Astrophysics Seminar

ABSTRACT: High speed impacts of large bodies on Earth launch ejecta on trajectories that transport them thousands of kilometers from the impact site. These events are recorded in discrete layers of sub-millimeter size spherules in sea floor sediments. Larger, rarer, and interestingly shaped objects are found on land. I will describe the physical processes that occur in energetic impacts. Emphasis will be given to the mechanisms that determine the sizes and shapes of the ejecta and the cooling of the fireball. An analogy will be drawn with processes that occur in the expanding universe. A possible relation to the origin of chondrules will be explored.