And so on. Thayer attributed the Washington 1952 sightings to weather-related anomalous propagation of radar signals, combined “most probably” with meteors and scintillating stars. The Rapid City-Bismarck sighting of 1953 was caused by a combination of (1) stars seen through an inversion layer, (2) at least one meteor, (3) AP echoes on radar, and (4) possible ghost echoes on ground radar and malfunction of an airborne radar gunsight. Thayer acknowledged that the commanding officer of the Rapid City detachment was doubtful of that last point.
Despite the many ways in which atmospheric phenomena can mislead the human and electronic eye, Thayer acknowledged a “small, but significant, residue of cases from the radar-visual files that have no plausible explanation as propagation phenomena and/or misinterpreted man-made objects.” One was a Utica case from 1955, in which an object was seen by a pilot and copilot and described as “light gray, almost round, with a center line.... Beneath the line there were several (at least four) windows which emitted a bright blue-green light. It was not rotating, but went straight.” Although the object was reported to be moving at above Mach 6, there was no sonic boom, a serious inconsistency, Thayer wrote. Still, he conceded that “it does appear that this sighting defies explanation by conventional means.”
Thayer’s most intriguing radar-visual case was the Lakenheath, U.K., incident of August 1956. This involved the tailing of an RAF fighter by an unidentified object. Thayer examined the possibility of atmospheric conditions, but to no avail. He commented that
this is the most puzzling and unusual case in the radar-visual files. The apparently rational, intelligent behavior of the UFO suggests a mechanical device of unknown origin as the most probable explanation of this sighting.
But this was too radical a conclusion without some qualifier: in this case, “the inevitable fallibility of witnesses,” which kept alive the possibility of a conventional explanation.
Despite, or because of, his dogged approach to arriving at conventional explanations, Thayer recommended several measures—all of which involved expending more resources—to improve UFO investigations. Thus, he parted ways with Condon and Craig as to whether UFOs warranted full-time study. Thayer appeared to be saying that they did.
Franklin Roach discussed astronaut sightings, mostly attributed to space debris seen under typically poor observational conditions. Still, three cases remained unexplained and “a challenge to the analyst.” Two were from the
The fifty-nine case studies constituted the heart of the book. Many of these reports showed impressive detective work to explain what initially appeared to be an extraordinary, and extraterrestrial, event. Others showed more signs of fanatical determination to debunk than investigative expertise. Within the fifty-nine cases studied, there were actually ninety UFO reports, of which thirty were not explained. Many of the explanations were on something of a sliding scale of probability, a reasonable way to do things, but not so easy to attribute hard quantitative results. Not all conclusions were clearly stated (as in Case 34, the Shag Harbor incident). Many were deemed to have insufficient data for analysis, or to have little probative value. One case did not belong in the study at all: the failure of a predicted UFO landing. Some of the unexplained cases nevertheless had the possibility of various conventional explanations proffered. Several explained cases were stretches that could only be attained by disregarding seemingly rational witness claims.
Looking at each of the fifty-nine case studies as a unit, however, the report produced sixteen cases in which the origin of the event could be considered unknown. Considering a total of fifty-eight cases (minus the nonevent), that produces an unexplained percentage of almost 28 percent. Of those sixteen cases, eight were what one might consider to be “good” cases, and two extraordinary. If
