Using personal computers and the Internet, scientists at the University of California at Berkeley plan to build a gigantic global "brain" to analyze interstellar radio signals for signs of life. If all those who have signed up for the software actually participate, SETI@home would represent the biggest radio search ever attempted. "We might get a million people involved in this project," said Dan Werthimer, an astronomer at Berkeley's Space Sciences Laboratory who is helping to run the project. "Everybody is curious, everybody wants to know if there is life out there. This is a neat way of letting them participate in the hunt."
Long a staple of big budget science fiction movies, the search for extraterrestrial intelligence - "SETI" for short - has usually been depicted as a job for professionals in control of huge telescopes. SETI@home aims to change all that.
Just a dot com away
By using "distributed computing," a new way of linking individual computers over the Internet, virtually anyone with a desktop PC could begin hunting for aliens.
"Distributed computing is one of the Holy Grails of computer science," said project director David Anderson, a computer scientist. "If it works, it could be 100 times faster than the fastest current supercomputer."
The SETI@home system would use the Internet to send individual computers chunks of raw data obtained from the Arecibo radio telescope in Puerto Rico, the largest "ear" to space that mankind has ever built.
Arecibo's huge dish scans the skies looking for radio waves that might have been produced by alien intelligence.
"We've been leaking television shows and radio programs into space for decades," Werthimer said. "Maybe somebody out there is doing the same - either sending out signals on purpose, or just leaking them the way we are."
The huge volume of radio data that must be analyzed has long been one of the main stumbling blocks for SETI projects. Even with fast new supercomputers able to complete as many as 200 billion operations per second, the number crunch has been a slow grind that leaves scientists frustrated.
That is where distributed computing comes in. Made possible by the rapid growth of the Internet, it allows scientists to break down large computing problems and distribute them through networks of smaller computers. Each computer solves its own small part of the puzzle, then feeds its answers back into the main computer to build an overview.
Distributed computing has been used in earlier projects including efforts to crack encryption codes and to figure out large prime numbers. But SETI@home will use it for a something that everyone can appreciate - resolving one of the biggest mysteries of the universe.
"We are confident that Earth's civilization is not the only one," said Bulgarian astronomer Veselka Radeva, who has signed up for SETI@home. "It is only a question of time to understand where and who are the other intelligent creatures in the universe."
Project managers say the users who have signed up for SETI@home range from a 12-year-old in the Philippines to Silicon Valley computer professionals. One of them, one day, may be lucky enough to retrieve Arecibo signals that indicate life exists in the stars.
"They won't know right away if their clunker was the one that found the extraterrestrial," Werthimer said, noting that the data would have to be rechecked and reanalyzed at project headquarters in Berkeley.
"But after the checks, and if we confirm it again, they will definitely get the credit for the discovery."
For that chance, project participants will not be asked to do much. Once the project is running, they will be able to visit the SETI@home Web site and download an analysis program and their first chunk of radio data from Arecibo.
Their personal computers will then begin searching through space in their free time. Appearing as a common "screen saver," the SETI program will kick in when the computer is idle and will not affect its normal operations.
"It will all happen automatically. You won't even know it is working on it," Werthimer said. When the computer finishes combing over its first block of data, it will connect back with the main project computer in Berkeley, send the data back, and get a new data package to work on.
"Everybody gets a little part of the sky, their own little bit of the information," he said. "There are 400 billion stars in our galaxy ... we need all the computing power we can get."
Even as he works on the SETI@home project, Werthimer is deeply involved in the SETI search as chief scientist for Project Serendip.
Casting a broader Net
Werthimer's project meshes with other SETI efforts, such as those conducted by the privately funded SETI Institute. The California-based SETI Institute is currently preparing for a weeks-long observing session at Arecibo, using different equipment and a different approach.
While the institute concentrates on a targeted search of nearby sunlike stars considered likely candidates for alien intelligence, Serendip takes a broad look at the sky in hopes that someone, somewhere, might be sending something our way. Serendip would provide the raw data to be analyzed by SETI@home's distributed network. The bulk of the estimated $200,000 still required before SETI@home's launch would pay for the expensive magnetic tapes used to record incoming radio data at Arecibo, organizers said.
Once the system is up and running, the key to success will be the participation of tens of thousands of E.T. buffs who are willing to use their personal computers for something other than e-mail.
"I'm optimistic on life on the universe. It would just be bizarre if we were the only ones," Werthimer said. "It might be that there is a galactic community out there and they are all talking to each other ... but we humans are just learning how." Reuters contributed to this story.