James McDonald’s case-by-case critique of Donald Menzel (1968)
Verbatim excerpts from Dr. James E. McDonald’s statement and prepared paper to the U.S. House Committee on Science and Astronautics, Symposium on Unidentified Flying Objects, July 29, 1968 — the section-by-section dismantling of Donald Menzel’s meteorological-optics UFO explanations. Source: files.ncas.org/ufosymposium/mcdonald.html (also project1947.com/shg/symposium/mcdonald.html; the prepared paper “Statement on Unidentified Flying Objects,” HCSA 1968). Primary support for menzel-harvard-debunker; companion to menzel-1968-symposium-statement-quotes (Menzel’s own statement) and 1968-house-symposium-unidentified-flying-objects.
Captured 2026-05-31. Minor obvious OCR garbles corrected in brackets; ellipses are McDonald’s or marked. McDonald cites Menzel’s two books as Ref. 24 (Flying Saucers, 1953) and Ref. 25 (The World of Flying Saucers, Menzel & Boyd, 1963).
The headline disagreement (oral statement)
Meteorological optics is a subject that I enjoy and have looked into over the years rather carefully, and I must express for the record my very strong disagreement with Dr. Donald H. Menzel, former director of Harvard Observatory, whose two books on the subject of UFO’s lean primarily on meteorological explanations. I have checked case after case of his, and his explanations are very, very far removed from what are well-known principles and quantitative aspects of meteorological optic[al] objects. He has made statements that simply do not fit what is known about meteorological objects.
I would be prepared to talk all day on specific illustrations but time will not permit more.
The summary verdict (prepared paper, “Misapplications of Atmospheric Physics”)
Since Dr. Menzel’s writings on UFO’s have evidently had, in some quarters, a marked effect on attitudes towards UFOs, I regard that effect as deleterious. If I felt that we were dealing here with just a slight difference of opinion about rather controversial scientific matters on the edge of present knowledge, I would withhold strong comment. However, I wish to say for the record, that I regard the majority of Dr. Menzel’s purported meteorological-optical UFO explanations as simply scientifically incorrect.
These extreme forcings of explanations recur throughout Menzel’s writings; one of their common denominators is lack of attention to relevant quantitative factors.
It has been just such casual ad hoc explanations as this by which Menzel has, in his writings, used meteorological optics to rationalize case after case with no attention to crucial quantitative details.
The case-by-case demolition
Chiles–Whitted (Montgomery, Ala., July 24, 1948)
Menzel (Ref. 24) first proposed that this was a “mirage”, but gave no basis for such an unreasonable interpretation. The large azimuth-change of the pilots’ line of sight, the lack of any obvious light source… the sharp pull-up, and the high flight altitude involved all argue quite strongly against such a casual disposition of the case. In his second book, Menzel (Ref. 25) shifts to the explanation that they had obviously seen a meteor. A horizontally-moving fireball under a cloud-deck, at 5000 ft., exhibiting two rows of lights construed by experienced pilots as ports, and finally executing a most non-ballistic 90-degree sharp pull-up, is a strange fireball indeed. Menzel’s 1963 explanation is even more objectionable, in that he implies… that the Eastern pilots had seen a fireball from the Delta Aquarid meteor stream. …the radiant of that stream was well over 90[°] away from the origin point of the unknown object.
Nash–Fortenberry (Newport News, Va., July 14, 1952)
Nash has stated to T. M. Olsen… that one of the most accurate accounts of the facts has been given by Menzel (Ref. 25), adding that Menzel’s explanation seems entirely out of the question to him.
Discussion. — Menzel explains this famous sighting as resulting from a searchlight playing on thin haze layers, an almost entirely ad hoc assumption, and one that will not account for the amber color, nor for the distinct edges, nor for the final climb-out of the objects.
Tombaugh (Las Cruces, N.M., Aug. 20, 1949)
The sighting by Dr. Clyde Tombaugh, discoverer of Pluto — six “windowlike” rectangles of light in a symmetric pattern crossing 50–60° of sky:
Discussion. — Dr. Menzel explains this phenomenon as resulting from reflection of lights from the ground, possibly “the lighted windows of a house” reflected by an inversion or haze layer aloft. The movement he explains as resulting from a ripple on the haze layer. Such an “explanation” is not merely difficult to understand; it is incredible. For an “inversion layer” to produce such a near-normal reflection of window lights would demand a discontinuity of refractive index so enormously large compared with anything known to occur in our atmosphere as to make it utterly out of the question. …In fact, I see no way of accounting for the Tombaugh observation in terms of known meteorological or astronomical phenomena.
The 5/24/49 White Sands balloon-tracking sighting (Charles B. Moore et al.)
Five witnesses tracked an object through >90° of arc with a theodolite. Menzel (Ref. 24):
“This incident, kept in the classified files for more than two years, presents no serious difficulty to the person who understands the optics of the earth’s atmosphere. The air can, under special conditions, produce formations similar to lenses… so can these lenses of air — imperfect though they are — form an image. What Moore saw was an out of focus and badly astigmatic image of the balloon above”
McDonald:
It would be interesting to hear Menzel present a quantitative defense of that astonishing disposition… Menzel adduces a “lens of air” to explain it away… Menzel is proposing that the atmosphere carried a refracted image of the balloon northeastward at a steady rate… that finally totaled several thousand times the magnitude of refractive angular image-displacements known to occur with bad seeing. I feel obliged to repeat an observation I have made before: If the transmission properties of the Earth’s atmosphere were as anomalous as Menzel assumes in his handling of UFO observations, he and his colleagues would be out of business.
Odessa / Washington F-94 (Dec. 10, 1952) — the Sirius error
Menzel (Ref. 25) explained the pilot’s report (an object that “did a chandelle in front of the plane, rushed away, stopped, and then made straight for the aircraft… at incredible speed”) as a mirage of a rising star:
“In the east, Sirius was just rising over the horizon at the exact bearing of the unknown object. Atmospheric refraction would have produced exactly the phenomenon described. The same atmospheric conditions that caused the mirage of the star would have caused anomalous radar returns.”
McDonald:
To suggest that a pilot would report that Sirius did a chandelle is both to forget realities of astronomy and to do injustice to the pilot. In fact, however, Menzel seems to have done his computations incorrectly, for it is easily ascertained that Sirius was not even in the Washington skies at 7:15 p.m. PST on 12/10/52. It lay at about 10 degrees below the eastern horizon. …Aircraft flying at altitudes of 26,000 ft do not get ground returns on level flight as a result of propagation anomalies.
Rosalia, Wash. B-36 (Feb. 6, 1953) — the “weather balloon”
Menzel concurred in the official “weather balloon” verdict, computing that winds would have carried a Fairchild AFB pibal over Rosalia. McDonald:
In fact, Rosalia lies 33 statute miles SSE of Fairchild, or about twice as far as Menzel indicates. …an examination of the upper-wind data… indicates that the winds at lower levels were blowing out of the southwest. …By that time, it would have been already east of Spokane, nowhere near Rosalia. …The light used on pilot balloons is a steady source… Furthermore, “circling climb” cannot be called “typical of a balloon’s course.” …there appear to be so many serious difficulties with the balloon explanation… that it is not possible to accept Menzel’s statement: “Thus all the evidence supports ATIC’s conclusion that the UFO was a weather balloon.”
Selfridge / Port Huron F-94 (1953) — radar “phantom returns”
Menzel, however, asserts that the pilot did see Capella, and that the airborne and ground radar returns “were merely phantom returns caused by weather conditions.” No suggestion is offered as to how any given meteorological condition could jointly throw off radar at the ground and radar at 21,000 feet, no suggestion… to account for [the] 180° course-reversal… With such ad hoc explanations, one could explain away almost any kind of sighting, regardless of its content.
Waldo Harris (Salt Lake City, Oct. 2, 1961) — the “sundog”
Menzel (Ref. 25) proposed that it was merely a sundog that Harris and the others were observing… But sundogs (parhelia)… occur at elevation angles equal to or slightly greater than the sun… To blandly suggest, as Menzel has done, that Waldo Harris… was fooled by a sundog is to ignore either all of the main features of the report or to ignore all of what is known about sundogs.
Arnold (Mt. Rainier, June 24, 1947) — the “mirage”
The 1947 sighting by [Ar]nold near Mt. Rainier is explained officially and by Menzel as a mirage, yet the objects which he saw (nine fluttering discs) changed angular elevation, moved across his view through an azimuthal range of about 90 degrees… Anyone familiar with mirage optics would find it utterly unreasonable to claim that such an observation was satisfactorily explained as a mirage.
The general method critique (mirages, inversions, “cloud reflections”)
A principal difficulty with Menzel’s mirage explanations is that he typically overlooks completely stringent quantitative restrictions on the angle of elevation of the observer’s line of sight in mirage effects. …mirage effects are confined to lines of sight that do not depart from the horizontal by much more than a few tens of minutes of arc. …In Menzel’s explanations… mirages are invoked to account for UFOs when the observer’s line of sight may depart from the horizontal by as much as five to ten degrees or even more. I emphasize that this is entirely unreasonable.
“Reflections off clouds” have been referred to repeatedly in Menzel’s writings, never with any quantitative discussion of precisely what he means. …What Menzel could possibly have in mind when he talks loosely about such cloud reflections… I cannot imagine.
[If] inversions were capable of producing the optical disturbances that Menzel has assumed, astronomers would long since have given up any attempt to study the stars by looking at them through our atmosphere.
The irony: Menzel’s own sighting
Menzel even describes a sighting that he himself made, over Arctic regions in an Air Force aircraft, in which the image of Sirius was enlarged to an angular size of over ten minutes of arc (one-third of lunar diameter). I have discussed that sighting with a number of astronomers, and not one is aware of anything that has ever been seen by any astronomer that approximates such an instance. …it would require such a peculiar axially-symmetric distribution of refractive index, which miraculously followed the speeding aircraft along as it moved through the atmosphere, that it seems quite hopeless to explain what Menzel has reported seeing in terms of refraction effects.
On Klass (the other atmospheric-debunker)
[Klass’] ideas have received some attention in magazines, [but] there is little enough scientific backup to his contentions that they are quite unlikely to have the same measure of effect that Menzel’s previous writings have had… Klass has ignored most of what is known about ball lightning and most of what is known about plasmas and also most of what is known about interesting UFOs in developing his curious thesis.
References as numbered by McDonald: Ref. 24 = Menzel, D. H., 1953, “Flying Saucers” (Harvard Univ. Press, 319 pp.); Ref. 25 = Menzel, D. H., & L. G. Boyd, 1963, “The World of Flying Saucers” (Doubleday, 302 pp.).