How Planet Hunting Works

Are we alone in the universe, or does life exist elsewhere? We have begun to search for extraterrestrial intelligence (SETI) by looking for radio transmissions from other civilizations. An important aspect of SETI is deciding where to look for these radio transmissions -- after all, the universe is an awfully big place. To refine the SETI searches, it is helpful to know which stars have planets… » Full Story on HowStuffWorks