Documents / Hearing transcript
This is the printed record of a July 29, 1968 symposium on unidentified flying objects held by the Committee on Science and Astronautics of the U.S. House of Representatives, chaired by Rep. J. Edward Roush. The committee heard statements from six scientists: J. Allen Hynek, James E. McDonald, Carl Sagan, Robert L. Hall, James A. Harder and Robert M. L. Baker. It also printed papers from Donald Menzel, Stanton Friedman, Frank Salisbury and others. Hynek argued that puzzling UFO reports from competent witnesses deserve serious scientific study.
“Leon Davidson”3 pages
81 yet the objects which he saw (nine fluttering discs) changed angular elevation, moved across his view through an azimuthal range of about 90 degrees, and were seen by him during the period when he was climbing his own plane through an altitude interval that he estimates to be of the order of 500 to 1000 ft. Anyone familiar with mirage optics would find it utterly unreasonable to claim that such an observation was satisfactorily explained as a mirage. Similarly, as has been noted above, the 1948 sighting by Eastern Airlines pilots Chiles and Whitted, once explained by Menzel as a "mirage", involves quantitative and observational factors that are not even approximately similar to known mirage effects. There are some extremely rare and still not well -explained refractive anomalies in the atmosphere, such as those that have been discussed by Min- naert, but good UFO observations are so much more numerous than those types of rare anomalies that it is quite out of the question ot explain the former by the latter. Sundogs, or parhelia, are a quite well-understood phenomenon of meteoro- logical optics. Refractions of the sun's rays on horizontally falling tabular ice crystals produce fuzzy, brownish -colored luminous spots at about 22 degrees to the left and right of the sun when suitable ice -crystal clouds are present. Rarer phenomena, produced by the moon rather than the sun, are termed paraselenae. Sundogs are relatively common, but it is probably true that many laymen are not really conscious of them as a distinct optical phenomenon. For this reason, it might seem sensible to suggest that some observers have been misled by think- ing that sundogs were UFOs. However, anyone with the slightest knowledge of meteorological optics talking directly to such a witness would, within only a few moments of questioning, establish what was involved. Instead of dealing with anything like a sharp -edged "object", one would quickly find that theobserver was describing a very vague spot of light which he saw to the left or right of the sun, probably very near the horizon. To blandly suggest, as Menzel has done, that Waldo Harris in the 10/2/61 sighting near Salt Lake City was fooled by a sundog is to ignore either all of the main features of the report orto ignore all of what is known about sundogs. Undersuns, sub -suns, can be seen rather frequently when flying in jet air- craft at high altitudes. They are a reflection phenomenon produced by horizon- tally floating ice crystals, which reflect an image of the sun (or at night the moon) and can give surprisingly sharp solar images in still air where turbulence does not cause appreciable tilting of the ice crystals. Here again, it is probablytrue that many laymen may be sufficiently unaware of this optical phenomenon that they could be confused when they see one. But, as with sundogs, the stringest quantitative requirements on the location of this optical effect relative to the sun would permit any experienced investigator to quickly ascertain whether or not an undersun was involved in this specific sighting. The effect involves specular reflection of the sun's rays, whence the undersun is always seen at a negative angle of elevation in which the observer's line of sight to the undersun is just as far below the horizon as the sun momentarily lies above that same observer's horizon. Clearly, many of the UFO cases that have been cited in examples given above do not come anywhere near satisfying the angular requirements for an undersun. In my own experience, I have already come across two or three reports, out of thousands that I have examined, where Iwas led to suspect that the observer was fooled by an undersun. "Reflections off clouds" have been referred to repeatedly in Menzel's writings, never with any quantitative discussion of precisely what he means. But the impression is clearly left that many observers have been and are continuing to be fooled by some kind of cloud -reflections. Aside from the above -described undersun, I am unaware of way "cloud -reflection phenomenon" that could produce anything remotely resembling a distinct object. Clouds of droplets or ice crystals do not provide a source of specular reflection (except in the case ofhorizontally -floating ice crystals observed from above with a bright luminary, such as sun or moon, in the distance—undersun). What Menzel could possibly have in mind when he talks loosely about such cloud reflections (and he does so in many different places in his books), I cannot imagine. Inversions are invoked by Menzel, and in official evaluations, to account for certain UFO sightings. Inversions produced by radiational cooling or by atmos-pheric subsidence are relatively common meteorological phenomena. In some cases, quite sharp inversions with marked temperature differences in rather small vertical distances are known to occur. It is such inversion layers that areresponsible for some of the most striking desert mirages of the looming type.
Hearing transcript, from the govinfo collection. The PDF is mirrored here; the original link is above. 256 pages are in the text index: search them above, or from the library's search.