In the United States, about 250,000 amateurs watch the heavens—and many of them have made significant contributions to science.

Saul Perlmutter changing our understanding of the entire universe by discovering that its expansion is accelerating.

A peek through the International Space Station's new windows [PIC].

A new computer model could predict "space weather" before it affects earth.

After the end of the disastrous space shuttle program, it's not at all clear where the space agency is going—or if it has enough money, skills, or buy-in to get there.

Hot on the trail of the first galaxies in the universe

Newly discovered planets are becoming ever smaller, lighter, and more familiar to us earthlings.

Bombing our closest neighbor pays off with a trove of information.

Could underground life be emitting methane clouds during warm periods?

Messenger shows how the surface was formed and how the surface forms the atmosphere.