Mars World That Never Was

Just about every two years, the planet Mars makes its closest approach to Earth around 36 million miles. Thats when we pack our robotic emissaries off to the Red Planet, timing their launches to spend the least effort to get there. These probes may pave the way for human explorers and, perhaps permanent settlers wholl [...]

The Incredible Journey of Apollo 12

It’s the ultimate buddy movie. Forty years ago, on November 19, 1969, astronauts Pete Conrad and Alan Bean landed on the moon in one of the most important of the Apollo flights. This video shows them making a pinpoint landing on a treacherous lunar surface, finding rocks, and generally having a blast. The program features [...]

How Large is the Universe?

The universe has long captivated us with its immense scales of distance and time. How far does it stretch? Where does it end and what lies beyond its star fields and streams of galaxies extending as far as telescopes can see? These questions are beginning to yield to a series of extraordinary new lines of [...]

The Largest Black Holes in the Universe

We’ve never seen them directly, yet we know they are there, lurking within dense star clusters or wandering the dust lanes of the galaxy, where they prey on stars, or swallow planets whole. Our Milky Way may harbor millions of these black holes, the ultra dense remnants of dead stars. But now, in the universe [...]