The SETI Institute, based in Mountain View, Calif., is currently conducting the world's most sensitive and comprehensive search for extraterrestrial intelligence, Project Phoenix. Phoenix searches for signs of other civilizations by listening for radio signals directly transmitted from other planets, or that just by chance may be heading toward Earth.
The National Aeronautics and Space Administration had been conducting its own Search for Extraterrestrial Intelligence program, but it was canceled by a budget-conscious Congress in 1993 (although the SETI program represented only 0.1 percent of NASA's budget).
Resurrected by private funding of $3 million from technology notables such as William Hewlett and the late David Packard, founders of the Hewlett-Packard Co., Gordon Moore, cofounder of Intel Corp. and Paul Allen, cofounder of Microsoft Corp., Phoenix began observations using a radio telescope in New South Wales, Australia, in February 1995.
Phoenix is targeting 1,000 stars for observation. By mid-1999, 50 percent of the stars listed had been looked at. Twice a year, astronomers from the SETI Institute make a pilgrimage from California to use the 304-meter-wide telescope at Arecibo in Puerto Rico -- the world's largest radio telescope, that had such a prominent role in the blockbuster movie "Contact," starring Jodie Foster.
"The observing begins when we fire up our three computer workstations," says Seth Shostak of the SETI Institute. "Unlike in 'Contact,' we don't use headphones to listen. Because we've got 28 million channels going simultaneously, computers handle all of the 'listening.' The software selects a star system to check out a likely target, and then I call up Jodrell Bank Observatory in England."
The 76-meter telescope at Jodrell Bank is the confirmation antenna. Any signals found in Arecibo are verified by the British dish. Within 20 minutes, the Phoenix two-telescope system can check out all interesting signals, a capability no other SETI system can match.
"However," Shostak says, "we are currently surveying only a tiny fraction of our star systems. So far, Phoenix has checked out only about one-billionth of the stars in our Galaxy. Primarily, we zero in on stars that are like our sun, with the kind of planets we think might have Earthlike similarities. These are the ones awash with water and wrapped in an atmosphere that have the capability to cook up intelligent life that might just be broadcasting our way. We still have a lot of celestial real estate to cover."
Other observatories are doing optical SETI, watching for possible signals in the visual wavelengths.
"We believe, however, that any civilization intelligent enough to know about radio signals would use them for communications," says Shostak. "Radio is very efficient. It doesn't take much energy to send out a bit of information."
SETI's role so far has been passive, limited to listening for aliens trying to contact us. A three-minute demonstration broadcast was made from Arecibo in 1974, however, and Shostak hopes someday to set up a broadcast experiment.
"Still," he notes, "our TV transmissions have been leaking into space for about 40 years already. Programs such as 'Mr. Ed' and 'Lucy' have reached several thousand stars. Hopefully, this shouldn't deter any interested parties!"
The institute, along with the University of California, Berkeley, is hoping to build the One Hectare Telescope in the next few years: hundreds of commercial satellite dishes spread out over California near Mount Lassen. Connected together, they would allow simultaneous scrutiny of huge chunks of our galactic neighborhood and make it possible to conduct the SETI all year round. Moreover, Project Phoenix's search is limited to 100 light-years away, but the One Hectare Telescope will allow a thorough mapping of the Milky Way out to 1,000 light-years.
Naysayers often argue that we as a civilization are not ready to find life on other planets. Are we ready for the concept that we are not alone in the universe?
"I am!" says Shostak. "Are you? If there ever was a time in history that we would be ready to accept the news that there are other life forms out there, I believe that time is now. Movies such as "Independence Day" and Spielberg's 'E.T.' have generated a mind-set of expectation and curiosity, if not outright acceptance. We think most of the civilizations capable of transmissions will be far more advanced than us, though, so it's going to be tough on our egos!"
So far, unfortunately, no signals from E.T. have been detected. Ultimately, though, the effort still seems worthwhile to Shostak.
"Ours is a voyage of discovery," he says, "but it's not clear what sort of ship we should use or in which direction we should steer. Maybe I'm standing on the deck of the Santa Maria and maybe not, but the voyage is exciting and the promise profound."