Ces soucoupes volantes

Ces soucoupes volantes sont-elles réelles ? Certainement, dit le Dr. Donald H. Menzel, professeur d'astrophysique à Harvard. Elles sont aussi réelles que des arcs-en-ciel. Personne ne devrait avoir honte de les voir et de les signaler. J'en ai vu moi-même.

D'un autre côté, dit Menzel, voir des soucoupes volantes n'est pas la même chose que de croire qu'elles sont des vaisseaux spatiaux pilotés par des êtres intelligents d'une autre planète. Cette approche science-fiction est comme "expliquer" la foudre en la qualifiant d'arme de Zeus : elle remplace juste un mystère par un autre mystère. Qualifier les soucoupes de vaisseaux spatiaux les explique, after a fashion, mais elle implique le mystère plus grand d'une super-race quasi-divine vivant sur Mars ou Vénus. Ce type de science est bien simpliste, dit Menzel, et bien mauvaise.

Raisonnement simple. Certains signalements de soucoupes sont des canulars ; certains sont des produits de l'imagination. D'autres sont venus d'observations furtives d'objets ordinaires comme des ballons météo, des appareils ou même des pages de journaux transportées par le vent. Mais Menzel est devenu convaincu que, en dépit de ces fausses alertes, des observateurs compétents et honnêtes avaient fait des observations inhabituelles qui demandaient des explications. Il se résolu à trouver par le seul raisonnement scientifique ce qu'ils avaient vu.

Les soucoupes varient beaucoup. Certaines sont des globes brumeux ; certains sont des lumières brillantes. Certaines ont la forme de cigares, "d'avions" sans ailes ; d'autres sont des disques tournoyants. Some of the saucers fly singly; others in formation. They fly both by day and by night; they zigzag abruptly. It is obvious, concluded Menzel, that no single type of object, such as a novel aircraft, can be behind all the stories.

Most striking things about the saucers are 1) their silence, 2) their habit of darting in violent zigzags and 3) their apparent high speed. Dr. Menzel does not take the reported speed at its face value. "Unless you know the size of an unfamiliar object," he says, "you cannot judge its distance, and unless you know its distance, you cannot judge its speed."

The speed of the saucers (apparent or real) is the principal prop of the spaceship theory. No man-made structural material, say the spaceship enthusiasts, could move through air at several thousand m.p.h. without being melted by the heat of friction. No style of aircraft known to man could move so fast in complete silence. No human crew could make the sudden stops and turns without being killed by "G-forces." Therefore, argue the space-shippers, the saucers must come from another planet where aeronautical technology is more advanced than on earth.

"How much simpler," reasoned Menzel, "to suppose that the saucers are not material at all. Then they need not obey the rules & regulations that govern material objects."

But what nonmaterial, saucerlike object can move quickly, silently, and in violent zigzags? One such thing is a spot of light. It is easy to swing the beam of a searchlight (across high clouds, for instance) and make its bright spot seem to travel at many thousand m.p.h. The spot of light moves silently and it can change direction as abruptly as any saucer.

Saucers reported by competent observers could not be explained by searchlight spots, but the beam-of-light analogy gave Menzel something to work with. He looked around for other tricks of nonmaterial light which might convince an observer that he had seen a material object zipping through the air at unearthly speed.

Radar Ghosts. He did not have far to look. During World War II, Menzel had left astronomy to become a radar expert. One job (as chairman of the Wave Propagation Committee of the Joint Chiefs of Staff) was to study the effect of atmospheric irregularities on radar waves. Sometimes a layer of warm air makes the waves wander oddly, producing deceptive ghosts on the radarscope. Warships have shelled empty ocean, thinking an enemy was there. Since light waves and radar waves behave in much the same way, Menzel reasoned that the same irregularities might produce optical ghosts resembling flying saucers.

Some optical ghosts are common: the ordinary mirages which nearly everyone has seen. Commonest of all is "water-in-the-road," which is caused by a thin layer of warm air above sun-heated pavement. The two layers (cold and dense above, hot and less dense below) "refract"* upward the light that reaches them from the distant sky. A motorist sees shining water (really sky) lying in the road. In hot deserts this sort of mirage is extremely deceptive.

Moon Disks. Menzel is convinced that rarer types of mirages explain most flying saucers. Part of his conviction comes from something he saw while driving across New Mexico from Holloman Air Force Base to Alamogordo. It was a clear, cool night and a full moon had risen. Menzel noticed near the moon two bright objects which he took at first for the stars Castor and Pollux. His astronomer's knowledge told him that Castor and Pollux would not be visible at that season, so he lowered the car window to get a better look. The stars turned into fuzzy disks with about one-quarter of the moon's diameter, and they kept up with the moon in its apparent motion past objects in the foreground. After five miles, Menzel told the driver to stop the car. At once the disks vanished.

Menzel wrote a report on this "sighting" and sent it to the Air Force. He never thought his disks were flying saucers; they were close to the moon and obviously associated with it. But they puzzled him for a long time. Now he believes they were caused by the motion of the car distorting a layer of warm air just above its roof and forming two displaced images of the rising moon. A more ignorant man might well have reported them as flying objects. At any rate, they led Menzel to his present theory about the saucers.

Normally, he explains, the atmosphere grows cooler as altitude increases, but under some conditions it may contain layers of warm air with cold air below them. These are called "inversions." They occur in all climates but are commonest in deserts, where both the ground and the air get very hot in daytime. As soon as the sun sets, the ground cools off, radiating its warmth into the sky. The air for a few feet up grows cool by contact with the cool earth, but the air a little higher stays warm.

This common condition, Menzel believes, is responsible for many of the saucer sightings (see diagram). The warm air overhead turns downward the light from bright objects, such as street lights or auto headlamps. If the "interface" is too turbulent, it can form no visible image, but if it is just steady enough, it will create bright images that seem to sweep rapidly across the dark sky. This is the explanation, says Menzel, for the famous "Lubbock Lights,"* which have been taken for interplanetary space ships flying in formation. They may be the images of a string of lights at a distance, or they may be reduplicated images of a single very bright light.

From an Airplane, Dimly. Other inversions produce other kinds of saucers. Sometimes a warm layer hangs several thousand feet up (see diagram). Often the layer contains dust, which increases its power to divert light. If an airplane is flying just above this layer, the pilot may see the dim displaced image of the sun, the moon or a high, brightly lighted cloud. The image will appear below him; it may be distorted, magnified, or in rapid motion. If the inversion has waves in its surface (common near mountain ridge's), the pilot may see a line of bright objects in rapid motion. Menzel believes that this is what Pilot Kenneth Arnold saw in 1947 when he reported the first flying saucers over a high ridge near Mt. Rainier.

If the plane is flying just below the inversion, the pilot may see distorted images from light sources below it. Such images can also be seen from the ground when the inversion is low enough. They may look like single moving objects or they may be lines of bright points shooting across the sky.

A special kind of flying saucer, says Menzel, has been seen four times, just after the launching of a big "sky hook" balloon. They appear as roundish objects, apparently at a great height. He believes that they are caused by the balloon itself when it rises through a thin layer of warm air at a thousand feet or so (see diagram). As it rises, it punches a hole in the layer. Cold air flows in, forming a blob of denser air that acts as an imperfect lens. Observers on the ground see a small moving image of the balloon above. The same effect can be produced, says Menzel, by holding a strong spectacle lens at arm's length toward a light.

Foo-Fighters. Another saucerlike object is the "foo-fighter": a bright spot of light which seemed to chase night-flying airplanes during World War II. Menzel believes that foo-fighters are really light (from the moon, from a plane's exhaust or from some other source) that is turned into the pilot's eye by strong eddies of air near a damaged wing. The moon disks that he saw himself were probably a sort of foo-nghter.

The only flying saucers which Menzel's theory does not explain are the green fireballs that have been reported with extraordinary frequency in the Southwest. But Menzel does not take them very seriously. In clear-aired New Mexico and Arizona, he says, meteors are seen oftener than in cloudier places. According to Menzel's colleague, Meteor Expert Fred Whipple, they often look green because of vaporized magnesium from their stony material.

After concluding that flying saucers are nothing but rare mirages, Menzel satisfied himself by mathematical analysis that air irregularities can cause them. But this theoretical treatment, he felt, was not enough. So he set about generating small-scale flying saucers in his basement laboratory.

Basement Saucers. He could not, of course, put several miles of atmosphere into a Cambridge basement, so he did the next best thing: he poured three inches of benzene into a straight-sided glass container. Over this he poured acetone, which is lighter. The two water-white liquids mixed only slightly, simulating an atmospheric inversion with the lighter warm air on top.

Then Menzel pointed a slender round beam of light from a projector at the underside of the invisible interface between the two liquids. Instead of passing through, the beam curved downward. When he looked directly into the downward slanting beam, he did not see a round spot of light. He saw an elliptical object, i.e., a perfect "flying saucer."

This laboratory saucer could "fly" too. When Menzel tilted the container, the image moved with the often-reported darting motion. When the liquid was stirred gently, the saucer changed shape, sometimes breaking into many fragments.

Prism Exhausts. Menzel does not claim to explain the exact air conditions that produce each flying saucer. The original light may come from almost any bright source, and it may follow all sorts of complicated paths, with different results each time. Sometimes the reported saucers have "glowing exhausts." Menzel believes that these "exhausts" are related to the colors seen through a prism. The conspicuous red, always seen at one end of the image, looks like a jet of red flame.

Since flying saucers are rare, they require unusual conditions to produce them. Menzel hopes that his rational explanation will encourage good observers to be on the alert for them.

While thinking scientifically about the flying saucers, Dr. Menzel has not neglected the colorful fancies of the spaceship cult. One of its articles of faith is that the space ships were first seen in the earth's atmosphere in 1947, not too long after the first atomic bomb was exploded in New Mexico. Their extraterrestrial designers―so the theory goes―wanted to see what ambitious man was up to. Ever since that time, the space ships have patrolled the U.S. Southwest, checking on atom bombs, rockets and other man-made threats to interplanetary peace.

Gay Nineties Saucers. "Who says that flying saucers were never seen before 1947?" asks Menzel. Recently he and his wife and young daughter visited the Library of Congress and found in the newspaper files a flying saucer scare more than 50 years ago. It started in California, where many flying saucers have been seen recently. "California had inversions then," says Menzel, "just as it has them today."

The first report came from Oakland. On the night of Nov. 22, 1896, people on an Alameda streetcar saw a huge "bird-shaped" object with a brilliant light hilts nose. "When first seen," said the Oakland Tribune, "the object seemed to be floating over San Leandro. It shot across the sky in the northwest, then turned quickly and disappeared in the direction of Haywards."

This was well before practical powered aircraft, but the object seen at Oakland was quickly named "the airship." It was soon seen in many other parts of California, where people lined up in the streets, hoping to catch a glimpse of it. Often it behaved exactly like a modern flying saucer, accelerating quickly and changing its direction suddenly.

During 1897, the "airship" was seen in many other parts of the U.S., including Salt Lake City, Denver and the Midwest. On April 10, reported the New York Herald, thousands of people in Chicago saw lights like an airship in the northwest. Some saw two cigar-shaped objects with green and red lights.

Unknown Lights. Even before this turn-of-the-century flurry, says Menzel, flying saucers were reported. In 1893, the British warship Caroline saw mysterious lights just south of Korea. They "flew" in a long line, sometimes changing their formation. Through a glass they appeared "to emit a thin smoke." On reaching Kobe, the officers of the Caroline learned that these "Unknown Lights of Japan" had been observed by fishermen and were even described in Japanese schoolbooks.

A search of literature, Dr. Menzel suggests, would turn up many flying saucers. There may even be some in the Bible: the "wheels" seen in the air by the Prophet Ezekiel.* Saucers have been seen more often of late, he thinks, because the U.S. Southwest, where atmospheric conditions are most favorable, has only recently been occupied by a large, alert population. The men who man its air bases, rocket ranges and laboratories are just the sort of observers that would notice flying saucers.

One aspect of his saucer research saddens Dr. Menzel. People like sensations, he says. The marvelous ships from space, manned by wise little people from Venus or Mars, brought a kind of frightening diversion into a jittery world. Dr. Menzel is aware that a debunker is not always a popular man. "I," he says sadly, "am the man who shot Santa Claus."

* Light moves slower in a denser medium. So when a "wavefront" of light passes at an angle from dense cold air into less dense warm air, the part that reaches the warm air first races ahead of the remainder. This "refraction" has the effect of bending the wave-front toward the cold air.

*Reported frequently over Lubbock, Texas. They look like "V"-shaped formations of bright spots in rapid motion.

* Ezekiel 1: 15-21.