You probably know that scientists now believe that the dinosaurs were wiped out by a huge meteorite impact 65 million years ago. You may not realize that the Earth has been bombarded repeated by meteorites large and small, and that there is a small but genuine risk that a large asteroid may hit the Earth during our lifetime. Dr. Fiske will discuss the evidence for meteorite impact on Earth as well as his recent work in southeast Asia. There, he is investigating evidence of a large meteorite impact that took place 700,000 years ago. Who are the presenters? Dr. Peter S. Fiske earned a Bachelor's degree in Geology at Princeton University and a Ph.D. in Geochemistry and Materials Science from Stanford University. He came to the lab in 1993. Dr. Fiske runs an experimental research facility that conducts impact studies. He has conducted field expeditions to study impact craters in Montana, Arizona, Thailand, Laos and Vietnam. This is the fifth presentation in this year's Science on Saturday lecture series. The series is co-hosted by LLNL's Science & Technology Education Program and Sigma Xi.