Few sightings of unidentified aerial phenomena have been more clearly described. Both witnesses were experienced pilots. Nash had flown more than 10,000 hours at altitudes of 7000 to 8000 feet and had held the rank of captain for eight years. Both men had been trained to observe accurately, to check and double-check every factor that might affect safe flying, and to regard the word “assume” as a potential killer. They shared the attitude of all cautious airmen: “In God we trust—everyone else, we check.”[[XII-5]] Unlike many UFO descriptions, their report distinguished rigorously between fact and inference, and it included the exact time of the sighting as well as the position, height, speed, and direction of flight of their plane. Using a kind of “instinct-judgment” gradually developed during their many hours in the air, they had made careful estimates of the position, height, speed, and direction of flight of the unknowns. Nevertheless, no reasonable explanation of the disks was found.
At the time of this incident flying saucers had been big news for many weeks. Both Life and Look magazines had recently published serious discussions of the possibility that flying saucers came from other planets, and newspapers were printing dozens of reports of weirdly glowing machines trailing fiery exhausts, streaking through the air at meteoric speeds (see [Chapter VII]). At ATIC, the small staff of nine men was swamped with saucer reports, far more than they could deal with properly, and some of the investigators were privately convinced that UFOs did come from outer space[[XII-6]]. For those or other reasons, the Norfolk sighting unquestionably received a less adequate study than would a similar incident today. The case was dropped and filed as an Unknown.
The incredible velocity and instantaneous change of course reported were obviously impossible for any earthly vehicle; no known metal could have escaped being melted by the frictional heat produced during so swift a passage through the dense atmosphere at 2000 feet, and no human flesh and bone could have survived the smashing inertial forces involved in the instantaneous change of direction. Nash and Fortenberry frankly stated their own conviction: “Though we don’t know what they were, what they were doing here or where they came from, we are certain in our own minds that they were intelligently operated craft from somewhere other than this planet.”[[XII-7]]
A Possible Explanation of the Nash-Fortenberry Disks
In the hope of solving the mystery, even though a decade has passed, the authors of this book have made a thorough study of the available evidence and present the results in the pages that follow.[[D]]
[[D]] We wish to thank Professor C. A. Maney and Captain W. B. Nash for their generous help with this problem. Although they do not agree with our conclusions, Professor Maney has kindly made available certain useful documents and Captain Nash in a lengthy correspondence has patiently answered a great many questions of detail.
When puzzling observations in a laboratory seem to point to a conclusion that contradicts the main body of scientific knowledge, the researcher first tries to repeat the experiment and duplicate the observations. If this is impossible, as with the Chesapeake Bay phenomena, he next re-examines the assumptions on which the conclusion is based. The belief that the UFOs had an extraterrestrial origin is based chiefly on two assumptions: first, that the estimates of the disks’ size, distance, and speed were reasonably accurate; and second, that the disks were solid objects. If either assumption is unsound, the extraterrestrial theory is unnecessary and the incident becomes much less of a puzzle.
Both witnesses were able and experienced observers. Nevertheless their determinations of distance and size, and hence of speed, are open to question because of the very fact that the disks were unidentified phenomena. Angular estimates are usually reliable when an observer is judging the position and speed of other known aircraft moving in the sky. But when the moving object is a strange one and is seen against an empty sky or flat ground containing no standards of comparison, estimates of actual size mean very little.
The ability to judge distance depends largely on the binocular vision of the observer’s eyes, separated by a span of about 2.5 inches. Focused on an object at 300 feet, they subtend an angle of about one fortieth of a degree, less than one tenth the diameter of the full moon. This is a physiological fact, and means that if the observer is more than 300 feet away from an object of unknown size, he cannot determine its distance accurately unless he knows how large it is or unless he can compare it with a known object. Using angular estimates, the witnesses in the Chesapeake Bay case calculated that at the point of closest approach the disks were a mile lower than the plane and about half a mile to the north—a distance of roughly 7000 feet. Mentally comparing their appearance with that of a DC-3 aircraft at this distance, the observers arrived at an estimate of size—whose accuracy depends on having a known distance. The circularity of this process indicates the weakness of all the estimates given. Even the most skillful observer cannot accurately judge the distance of an unidentified object when he does not know its true size, and he cannot judge the size unless he knows its actual distance.
Over Norwich, Connecticut, on May 15, 1962, a cloudless day with perfect visibility, a Navy aircraft and a commercial-airlines plane reported a near collision at about 7000 feet. The Navy pilot filed a complaint, stating that the two planes had missed each other by a distance of only about 600 feet. According to the commercial pilot, who did not file a complaint, the planes had had a leeway of about 4000 feet—a more than sixfold difference![[XII-8]]. Thus good pilots can differ widely in estimating the position of objects in the sky, even known aircraft seen in full daylight. With an unrecognized phenomenon seen in darkness or in semidarkness, as in the Chesapeake Bay case, good estimates are impossible.