A check of the astronomical situation showed that the sun had set about three hours before the sighting. Venus was following roughly three hours behind the sun and was extremely brilliant, with a magnitude of nearly -4.0. At 7:48 P.M., when the pilot sighted the unknown, the planet was about 3 degrees above the western horizon. When Venus finally sank beneath the horizon and disappeared, the “unknown” also vanished. The similar UFOs reported from Japan during the same period, on January 9 and January 21, 1953, were also mirages of the planet Venus. The cases of “The Rotating Lights of Japan” in the Air Force file on UFOs have now been shifted from the category “Unknown” to the category “Solved.” In many other UFO cases of the “rotating lights” variety, the Air Force has positively identified the unknown as the planet Jupiter. _UFOs and the Opposition of Mars_ Venus is not the only heavenly body to simulate a flying saucer. Jupiter and even Mercury, the smallest of the planets, have inspired their share of UFOs. Mars, which can also be very bright, has frequently been reported as a spaceship. On June 21, 1952, an F-47 aircraft was on routine patrol over the Atomic Energy Commission installation at Oak Ridge, Tennessee, when at 10:58 P.M. a spotter from the Ground Observer Corps informed the pilot that a slow-moving craft was moving in the area at very high altitude. At about the same time the pilot observed a blinking white light, of no definite shape and with no exhaust or trail, apparently making passes at him. For the next eighteen minutes the pilot tried vainly to intercept the unknown. The plane was at 15,000 feet, moving at about 250 knots. As the pilot turned to meet the pass, the UFO would pull up some 4000 to 5000 feet above the plane and then move in again. When the plane reached 22,000 feet, the UFO appeared to make a final dive from 28,000 feet, pulled back up to its previous altitude, and then disappeared. The pilot’s reaction is indicated by his answer to one of the routine questions on the Air Force report form: “Did you stop at any time during the sighting?” His reply read: “Ha Ha!” Investigating the incident, officials from ATIC at first suspected that the object might have been a balloon, released as a hoax; only a few weeks earlier a crank had launched a flight of balloons near Oak Ridge and had been caught. But after interviewing the witnesses, the investigators concluded that the UFO was far more probably the planet Mars. As so often happens, however, they could not convert the “probable” into a “positive” identification because they lacked one essential fact: the bearing of the aircraft[IV-1].