Thirty years after the first exoplanet was found in 1995, NASA's counter of confirmed worlds outside our Solar System crossed ...

Aliens have long been a staple of science fiction. Yet the possibility of intelligent life beyond Earth is more than a matter of imagination—it is also a subject of serious scientific inquiry.

This article predates the current owners of Science Blog. It has not been reviewed under the current editorial process and is kept as part of the archive. Four hundred light years away, a planet ...