Mock suns have been the cause of many UFO sightings. Even after several publications [see [[XII-1a]] explained how the sun reflected from ice crystals could account for some of the reported flying saucers, this idea was largely ignored by early investigators who had a limited training in the physical sciences.
Sundogs are relatively uncommon. Few airmen, even those with long experience, have learned to recognize them. In a poll of both commercial and military pilots, Dr. Menzel found that only one in five knew what a sundog was and how it might look in the sky. Two of three generals in the Air Force, similarly, were unfamiliar with the phenomenon. Like balloons, sundogs have a silvery metallic sheen. When observed from the ground, they seem to hover or move very sluggishly; to a witness in the air they seem to move rapidly, to pace the plane, or to take evasive action as though under intelligent control. When enough data are available, and the time of day and the position of the unknown relative to the sun are appropriate, a mock sun should be considered as a possible explanation of the UFO.
A sundog seen from a plane can suggest a spectacular and fantastic structure, like the one reported over Rheims, France, at 2:30 P.M. local time on March 31, 1960. The pilot and crew of a C-47 plane described the unknown as like a gigantic spool of thread some twelve feet tall. The neck of the spool, about six feet in diameter, seemed to be capped at top and bottom by disks eight or ten feet in diameter. The upper disk was reddish, the lower, blue-green. The plane was flying at 6000 feet and had just passed from a storm area into a region of calm with unlimited visibility. The UFO remained in view for about sixty seconds, then suddenly vanished. From an analysis of the data, the position of the unknown relative to the sun and the observers, and the weather situation, Air Force investigators positively identified the object as a mock sun[XII-1].
One of the most recent sightings of this type occurred on October 2, 1961, a few minutes after noon[XII-1]. A civilian pilot who was just taking off from the Utah Central Airport at Salt Lake City noticed a bright silvery disk in the air ahead of his plane. He supposed it to be another aircraft crossing his course. When he was air-borne, he was surprised to find that the object, now an elongated pencil shape, still appeared in the same position where he had first seen it and hence could not be a plane. Puzzled, he radioed the control tower and reported the UFO. Looking south as directed by the pilot, the tower operator easily found the object, a bright spot in the sky directly below the sun and apparently hovering over the town of Provo, forty miles to the south.
Deciding to investigate, the pilot left the traffic pattern and started directly south after the UFO. It seemed to be standing practically still in the sky, with a little rocking motion, at an altitude of 6500 to 7000 feet. He seemed to have approached within three to five miles when the UFO suddenly shot up “like an elevator” and retreated rapidly south, as though taking evasive action. The acceleration was tremendous, almost as though the UFO had been fired from a rocket, but there was no vapor trail and no sound. It then disappeared, gradually. “It just faded out. I kept my eyes glued right on it because I could see it was moving away at a great speed. I wanted to see how long it would take and it was just a second or two until it had faded completely. And it was getting smaller all the time, you could see it was moving away.” The speed of departure, the pilot estimated, must have been thousands of miles an hour.
Alerted by the pilot’s message to the control tower, several persons on the ground at the Salt Lake City airport, most of them with experience as pilots, had also been watching the UFO. Ground observers at the Provo airport, also alerted, were not able to locate the unknown, even though they had been told it was almost directly overhead.
Investigators from a nearby Air Force Base interviewed the witnesses, who were obviously competent and reliable. All agreed that the unknown had been a bright, silvery, metallic-looking object that seemed to glisten or flicker in the sun; that it was roughly oval or indeterminate in shape; that it was solid and tangible, but not a conventional aircraft or balloon; that it made no sound, showed no exhaust or vapor trail; that it was in view roughly fifteen minutes, and disappeared gradually by “blotting out” or fading. All but one of the witnesses agreed that the skies had been absolutely clear and cloudless; one stated that, although the day was clear, a very slight haze existed over the mountainous region where the UFO appeared.
In spite of this general agreement, certain significant discrepancies became evident. The pursuing pilot stated that the object had moved up and away from him at incredible speed, as though it were controlled. The ground observers, however, did not see any movement by the UFO. Most of them reported that it remained stationary as though it were suspended in the air; a few said that it vanished at intervals, only to reappear a few seconds later in another place. Most of the time, they agreed, it just hung in the sky until it faded from view.
By analysis of these clues, ATIC was able to solve the mystery. According to the local weather bureau, the sky had been clear with visibility unlimited, but there had been very thin cirrus clouds, a layer of minute ice crystals suitable for producing a mock sun. A sundog would also account for the contradictory statements about the UFO’s motion. Since the ground observers remained in one place, their position relative to the sundog did not change and it seemed to remain stationary. The pilot, however, was in a moving plane and changing his position relative to the UFO; hence it seemed to move rapidly away from him. In the same way a rainbow seems stationary to a person who merely stands and watches it. But if he begins to chase it, hoping to catch up and perhaps find the legendary pot of gold, the rainbow seems to move away and elude its pursuer. The pilot’s belief that the UFO had exhibited fantastic speed was, according to his own statement, an inference based on the fact that the UFO quickly dwindled, became very small, and vanished. It disappeared, however, not because it was speeding away at thousands of miles an hour, but because of a change in the relative positions of sun and ice clouds that produced the sundog in the first place. One final point nailed down this explanation. The angular distance between sun and UFO was exactly that to be expected between sun and mock sun, at that time and place.
The details of this sighting obviously show a striking resemblance to some of those in the Mantell case ([p. 33]), in which the UFO and the sun had the same bearing from the pursuing plane as in the Salt Lake City incident. With the information now available, there can be little doubt that Mantell was actually chasing a Skyhook balloon. But in 1948 when so many of the relevant facts were not known, the sundog theory was a reasonable solution and may still be the correct one.