Countdowns
06 January 2008, 02:07 PM ET
Humans have sent many missions, both manned and robotic, beyond our planet to explore our neighboring celestial bodies.
01 May 2006, 01:13 PM ET
As a longtime investigator of unusual phenomena, I have no doubt that UFOs exist.
07 July 2003, 04:00 PM ET
See questions and answers about the Columbia Accident Investigation Board's (CAIB) final report.