Countdowns
26 October 2010, 10:30 AM ET
Take a tour of the effect Sputnik, the world's first artificial satellite, has had on science 50 years after its launch.
25 October 2010, 06:31 PM ET
Our solar system's planets vary greatly in size, composition, temperature, chemistry and geology. Here are some notable extreme facts about the planets that orbit our Sun.
19 October 2010, 07:32 PM ET
The age of private spaceflight is almost upon us with a veritable fleet of new commercial spaceships rolling out to the launch pad. As NASA iconic space shuttles retire for good, here's a look at new private ships soon to be reality
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.