© 2009, 1998 WGBH Educational Foundation. All Rights Reserved.

Adapted from A Science Odyssey: Short Trips "I Feel the Earth Move", A Science Odyssey with Charles Osgood, produced by WGBH/Boston. Third party materials courtesy of Department of Defense, Library of Congress, NASA, Peace River Films, Inc., Photo Researchers, and Tepley Moonlight / Lee Tepley. Animation courtesy of Salvatore Raciti.