Stephen Hawking and daughter Lucy speak at NASA lecture series in Washington

Stephen Hawking, astro-physicist and professor at the University of Cambridge, delivers a lecture entitled "Why We Go into Space" as a part of a lecture series honoring NASA's 50th Anniversary, at the George Washington University in Washington on April 21, 2008. Hawking spoke on the benefits of space travel and said we should be actively perusing a colony on the moon and a manned Mars mission. (UPI Photo/Kevin Dietsch)