IT'S one of humanity's grandest questions: Are we alone in the universe? Engineers now have powerful new technology to help search for an answer. And that's why even though Congress doesn't want to fund such research any longer, the public hasn't let the Search for Extra Terrestrial Intelligence (SETI) die.
Planetary Society members, for example, have just matched a $100,000 challenge gift from Micron Technology Inc. to upgrade the SETI observatory managed by Harvard University Prof. Paul Horowitz. This will supply advanced computer-memory chips for listening equipment that would have been impossible to build a decade ago when the observatory in Harvard, Mass., began its SETI program.
Meanwhile, the SETI Institute of Mountain View, Calif., is finishing a survey of nearby stars in the southern sky in cooperation with Australia's Parkes Observatory. The 210-foot radio telescope at Parkes is the largest radio telescope in the Southern Hemisphere. Temporarily outfitted with the institute's specialized radio-detection equipment, it has become a sensitive listening post for alien signals.
This is part of a larger, privately funded search program that the institute calls Project Phoenix. Like the legendary phoenix that rises newborn from its funeral pyre, the project revives some of the National Aeronautics and Space Administration's SETI program that Congress killed in 1992. It has refined the NASA-developed radio detectors and picked up part of NASA's planned survey of selected stars. Phoenix has a list of 1,000 stars closer than 150 light-years away that seem likely to have planets. About 200 of them are visible only from the Southern Hemisphere. Hence the cooperative search with Parkes Observatory, which is about six hours' drive west of Sydney.
Like other SETI searches, this one listens to a band of radio frequencies between 1,000 and 10,000 megahertz where there is little cosmic radio interference. This search specifically targets 28 million channels from 1,200 to 3,000 megahertz. If a suspicious signal is detected, analyzer equipment linked to a 72-foot auxiliary radio telescope 150 miles away checks it out.
So far, roughly 100 stars have been checked with no signals yet detected. The observation program ends May 31. Then a two-week ''open'' observation period follows during which other teams can use the equipment before it returns to California.
If Phoenix is to continue, it needs more money. Its present funds run out by the end of June. Project officials say they are hopeful that donations will continue. But there are no guarantees.
Meanwhile, with his funding for new equipment now in hand, Harvard's Dr. Horowitz says ''we have a fire under our tail'' to get that equipment on line later this year. Largely with the help of Planetary Society funding, Horowitz and teams of graduate students have been using Harvard's 85-foot radio telescope in an automated 24-hour-a-day SETI project targeting selected frequencies. Equipment that has been running for 10 years listens on 8.4 million channels at once. The new equipment will be able to tune in a quarter of a billion channels simultaneously. It will also have enhanced capability to screen out human-made radio interference and check out suspicious signals.
Horowitz already has detected at least five such ''signals.'' But they all vanished when he tried to double-check them. He notes wistfully: ''We've definitely had a signal from an intelligent civilization. But we can't tell if it's from this world or from out of this world.''
No one said SETI could be easy. If it's like looking for needles in a haystack, then only a small area of the haystack edge has been searched so far. Yet it goes to the heart of the question of humanity's place in the universe. And for the first time in human history, we can address that question scientifically rather than leaving it to philosophical and religious speculation. Although funding remains precarious, this new science-based quest has been intriguing enough for private donations to keep it going.