Software hunts for aliens in free time

Supercomputer: In the search for life in the universe, screen savers link home computers to scan radio signals.

May 24, 1999|By Michael Stroh | Michael Stroh,Sun Staff

Want to join the global hunt for E.T.? All you need is a PC.

Last week a small band of scientists involved in the Search for Extraterrestrial Intelligence (SETI) unveiled free software that turns home computers into alien trackers.

The software, called SETI@home, runs on both Windows- and Macintosh-based machines and works like a screen saver. Instead of showering the screen with flying toasters when the computer is idle, the software plucks data representing raw signals from a SETI radio telescope in Puerto Rico and combs the numbers for signs of alien communiques.

"There's a small but captivating possibility that your computer will detect the faint murmur of a civilization beyond Earth," announces the project Web site.

Long the dark horse of science, SETI is on a roll these days. Astronomers are discovering planets outside our solar system on a regular basis, fueling renewed speculation that we are not alone. The University of California at Berkeley this year created the first academic chair dedicated to the hunt for alien life and announced it would build a new radio telescope for SETI searches. Alien hunters at Harvard University, meanwhile, have developed new technology to search the heavens for optical signals from E.T.

The SETI@home project is also cutting-edge. By tethering home PCs over the Internet, SETI researchers are turning thousands of small computers into one giant computer. The concept, known as "distributed computing," is an attempt to overcome a long-standing hurdle: SETI researchers accumulate far more radio telescope data than they can analyze.

Nearly 150,000 copies of the SETI@home software were downloaded off the project's Web site in the first 24 hours of its release. "That already makes this the largest supercomputer in the world," says project scientist Dan Werthimer of the University of California at Berkeley.

Volunteers, in essence, get their own tiny piece of the sky to work on. A central computer in Berkeley dishes out a 350,000-byte chunk of radio telescope data to each home PC over the Internet. The exchange occurs when a participant logs on to check e-mail or surf the Web.

Like a typical screen saver, SETI@home kicks in when the computer sits idle for a few minutes, sifting through the astronomical data for patterns that stand out from the background hiss of the universe. Even if the software finds a blip in the glop, it's more likely to be "terrestrial pollution," stray radiation from broadcasters, satellites, low-flying aircraft or even heavy trucks.

Once the false positives are weeded out, signals that still appear unusual will be set aside for further review by SETI scientists.

What happens if you're the one who finds E.T.?

"Maybe you and I will share the Nobel Prize together," says Werthimer, who has spent two decades on the hunt without finding a signal worthy of second review.

"But don't hold your breath."

To learn more about SETI@Home and download the free software, visit You'll need a computer with at least 32 megabytes of RAM, 10 megabytes of free hard drive space, and an direct or dialup Internet connection. The software takes about 5 minutes to download on a 28.8-Kbps modem.

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