Looking for alien life from home.

Searching for signals of extraterrestrial life has become all the rage among earthlings. Since May, more than 1 million people have downloaded software that sorts through signals collected by the Arecibo radio telescope in Puerto Rico, which is looking for patterns that an intelligent extraterrestrial might have created.

Dubbed SETI@home, the program requires only a desktop computer and acts like a screensaver, crunching data when the computer is idle. The analysis shows up on the user's screen and then is routed back to researchers at the University of California, Berkeley, who consolidate the data.

"SETI@home is now the largest computation ever done on this planet--we've accumulated more than 50,000 years of computing time," says project scientist Dan Werthimer of Berkeley. The software's widespread use illustrates the power of distributed computing, in which large computations are split among many small computers.

Sporting a receiver 300 meters in diameter, Arecibo is the world's largest single-dish radio telescope. It records radio emissions around the clock. Since the inception of SETI@home, scientists have dramatically diminished the telescope's backlog of data. They are now updating the software so it can search for more complex signals from space. So far, no sign of alien life has turned up.

To help with the search, go to either of the following Web sites: http://setiathorne.ssl.berkeley.edu or http://planetary.org.