Watch NOVAs

Asteroid (Oct. 2006)

Will a doomsday rock the size of the Rose Bowl hit Earth in 2036? Watch now (12 mins.)

Astrospies (Feb. 2008)

An elite corps of secret U.S. astronauts is trained to gather intelligence on the Soviets during the Cold War. Watch now (49 mins.)

Don't Ask the Expert (Oct. 2006)

Neil deGrasse Tyson has a bone to pick with Hollywood aliens. Watch now (2 mins.)

The Elegant Universe (Oct. 2003)

Eleven dimensions, parallel universes, and a world made out of strings. It's not science fiction, it's string theory. Watch now (146 mins.)

Hubble's Amazing Rescue (Oct. 2009)

The unlikely story of how the world's most beloved telescope was saved. Watch now (50 mins.)

Hunt for Alien Earths (July 2009)

Astronomers may be on the brink of finding Earth-like planets beyond our solar system. Watch now (15 mins.)

Hunting the Edge of Space: Part 1 (Apr. 2010)

How telescopes have expanded our view of the universe Watch now (50 mins.)

Hunting the Edge of Space: Part 2 (Apr. 2010)

How telescopes have expanded our view of the universe Watch now (50 mins.)

Is There Life on Mars (Dec. 2008)

The decades-long search for life on the Red Planet heats up with the discovery of frozen water. Watch now (50 mins.)

Monster of the Milky Way (Oct. 2006)

Does a supermassive black hole lurk at the center of our galaxy? Watch now (48 mins.)

Moon Smasher (July 2009)

A NASA satellite called LCROSS heads to the moon in the hope of finding buried water. Watch now (15 mins.)

Origins: Back to the Beginning (Sep. 2004)

How did the colossal forces of the early universe make it possible for habitable worlds to emerge? Watch now (50 mins.)

Phoenix Mars Lander (July 2008)

NASA's latest robot has already found frozen water and is looking for more signs that the Red Planet could support life. Watch now (12 mins.)

The Pluto Files (Mar. 2010)

Take a cross-country journey with Neil deGrasse Tyson to explore the rise and fall of America's favorite planet. Watch now (50 mins.)

Profile: Franklin Chang-Díaz (July 2009)

The first Latino-American astronaut is also a scientist designing a new generation of plasma-powered space vehicles. Watch now (15 mins.)

Saving Hubble (July 2008)

Two teams of spacewalkers take on the risky mission of reviving the ailing Space Telescope. Watch now (13 mins.)

The Search for ET (July 2008)

Astronomers have their radio telescopes tuned to receive signals from alien worlds. But is anybody out there? Watch now (11 mins.)

Space Elevator (Jan. 2007)

Can we build a 22,000-mile-high cable to transport cargo and people into space? Watch now (13 mins.)

Space Shuttle Disaster (Oct. 2008)

An investigation uncovers the human failures and design flaws behind the 2003 Columbia tragedy. Watch now (50 mins.)

Space Storms (July 2008)

Behind the dazzling display of the aurora borealis are space storms that could turn the lights off here on Earth. Watch now (10 mins.)

Sputnik Declassified (Nov. 2007)

Top-secret documents rewrite the history of the famous satellite and the early space race. Watch now (49 mins.)

10th Planet (Jan. 2006)

A stunning discovery at the far reaches of our solar system raises questions about what makes a planet a planet. Watch now (5 mins.)