ARE WE ALONE? UFO sightings are down, and the saucer spotters are getting skeptical. What on Earth is going on? By Jonathan Margolis On a starlit night in Northern England, Philip Mantle, a printer by day and for 13 years an investigator of unidentified flying objects, is roused out of bed to inspect what sounds like the mother and father of all alien spacecraft landings. An excited 3 a.m. phone caller has reported that hovering above the mill towns of Huddersfield and Dewsberry is a flying contraption straight out of STAR TREK. Mantle arrives on the scene, glances at the putative starship with out-of- planet license plates and announces, "That's extra-terrestrial all right. It's the planet Venus." Beam us down, Scotty! The heady days of close encounters and flying saucers with unearthly beings appear to be numbered. Mantle, an internationally acclaimed figure in his spacy field, is one of a new breed of UFOlogists who do not believe that UFOS come from outer space. He and his like-minded peers are happy to give sober interpretations even of apparently mysterious sightings by reliable observers such as pilots and policemen with no known history of lunacy. Earlier this month the new-style UFOlogists gathered for an inter- national conference in Sheffield, Britain, entitled "ET or Not ET: Should That Be The Question?" Organizer Mantle and other enthusiasts explained away flying saucers as man-made objects, natural phenomena or para- psychological events that in other cultures and settings have given rise to the notions of fairies, ghosts, occult systems, visions of angels and even chariots of fire. "There's no way on earth that you can test the extraterrestrial hypothesis," says Mantle. "We don't have a dead alien or a piece of crashed spacecraft to give scientists. Thirteen years ago, I was quite convinced we were being visited by aliens. Now I'm not. Even with my involvement in the subject, I can't find any evidence that UFOs are extra-terrestrial." In Western Europe at least, even evidence in the form of UFO sightings is fast disappearing. It may be a function of earthly worry caused by recession, or a fading of fear now that the cold war is over, but 1992 has not been a vintage year for strange flying objects, be they saucers or cigars. Hard data are hard to come by, and the picture is confused by competing reports from rival UFO-spotting organizations, but a downward trend, even a collapse, in the sightings market is evident. Last year Belgium, apparently a glittering earthly beacon for space travelers because of its fully lighted auto route system, was a veritable magnet for UFOs: more than 2,000 sightings were recorded by the country's National UFO Center. This year the center has tallied just 50 accounts. In Britain in the late 1980s there were hundreds of sightings every year; there have been 56 so far in 1992. The numbers are similarly down in Spain and Scandinavia. U.S. UFOlogists say there are fewer sightings, but there's a catch. In blatant defiance of the 1932 antikidnapping Lindbergh Act, extra- terrestrials reportedly have been luring more Americans into their space- craft and subjecting them to medical examinations, often extracting sperm and eggs from their specimens. Philip Klass, a Washington-based electri- cal engineer and leading debunker of UFO stories, is bemused by the abduc- tion epidemic in his country. "Either ETs regard American sperm and ova as superior to that of other nations," he says, "or there are more kooks in the U.S." Old-style UFO loyalists maintain that the dip in sightings is merely a cyclical lull that has happened before. But it does not take a Ph.D. in astrophysics to note that the flying saucers arrived on the scene with the cold war in the late 1940s and are apparently winding down operations now that the war is over. The Belgian outbreak, especially severe in late 1990, was probably the result of people seeing Stealth bombers in pre-Gulf War operations, according to one cautious British UFO buff at the Shef- field convention. A current proliferation of UFO sightings in the former Soviet Union coincides not with the return of vodka to store shelves but with a rash of all forms of mysticism and quackery -- a payoff, according to a Russian academician writing last year in SCIENTIFIC AMERICAN, of the breakdown of the first "scientifically designed" society. It will be ironic if 1992 sees the beginning of the end for the little green man. On Oct. 12, NASA, the agency that UFO-conspiracy theorists have long held responsible for hushing up information on space invaders, is scheduled to begin searching for extraterrestrial intelligence through an electronic listening plan that will attempt to eavesdrop on ETs phoning home. With once credulous fanatics demanding scientific proof before they will believe that UFOs come from space, the NASA project will doubtless be a nugget of good news for alienated aliens. There is another. In Britain Lord Hill-Norton, a former Admiral of the Fleet and chairman of NATO's Military Committee -- the sort of person blamed for covering up UFO stories -- has in retirement come out as a pro-extraterrestrial. "I am quite certain UFOs are not terrestrial," he declared last week. "My position while serving was such that I would have known if UFOs were military devices. They are not." Beam us back up, Scotty!