The Asteroid That Thought It Was a Comet

The difference between an asteroid and a comet was always thought fixed—but now a new paper says the two celestial bodies may be more similar than we thought

50 Years of Pictures From Space

For half a century, the U.S. has been sending probes into deep space—and for half a century the appropriately named Deep Space Network has been keeping in touch...

How Greenhouse Gasses Saved Mars

The same heat trapping processes that are causing so much trouble on Earth once made Mars a very pleasant place