James E. McDonald statement, Symposium on UFOs, House Committee on Science and Astronautics

1. Case 20. Las Cruces, N.M., August 20, 1949:
A good account of the sighting by Dr. Clyde Tombaugh, discoverer of the planet Pluto, is given by Menzel (Ref.
25). From my own discussions with Dr. Tombaugh, I confirmed the main outlines of this incident. At about 10:00
p.m. on 8/20/49, he, his wife, and his mother-in-law were in the yard of his Las Cruces home, admiring what
Tombaugh described as a sky of rare transparency, when Tombaugh, looking almost directly towards zenith, spotted
an array of pale yellow lights moving rapidly across the sky towards the southeast. He called them to the attention of
the two others, who saw them just before they disappeared halfway to the horizon. The entire array subtended an
angle which Tombaugh put at about one degree, and it took only a few seconds to cross 50 or 60 degrees of sky. The
array comprised six "windowlike" rectangles of light, formed into a symmetric pattern; they moved too fast for
aircraft, too slowly for a meteor, and made no sound. Menzel quotes Tombaugh as saying, "I have never seen
anything like it before or since, and I have spent a lot of time where the night sky could be seen well."
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. However, 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.
It is a simple matter to show that even inversions of intensity many orders of magnitude larger than have ever been
observed yield reflectivities (at the kind of near-normal incidence involved in Tombaugh's sighting) that are only a
tiny fraction of one per cent (Ref. 36). In fact, I see no way of accounting for the Tombaugh observation in terms of
known meteorological or astronomical phenomena.
2. Case 21. Ft. Sumner, New Mexico, July 10, 1947:
A midday sighting by a University of New Mexico meteoriticist, Dr. Lincoln La Paz, and members of his family
was summarized by _Life_ magazine years ago (Ref. 37) without identifying La Paz's name. Bloecher (Ref. 8) gives
more details and notes that this is officially an Unidentified. At 4:47 p.m. MST on 7/10/47, four members of the La
Paz family nearly simultaneously noted "a curious bright object almost motionless" low on the western horizon, near
a cloudbank. The object was described as ellipsoidal, whitish, and having sharply-outlined edges. It wobbled a bit as
it hovered stationary just above the horizon, then moved upwards, passed behind clouds and re-emerged farther
north in a time interval which La Paz estimated to be so short as to call for speeds in excess of conventional aircraft
speeds. It passed in front of dark clouds and seemed self-luminous by contrast. It finally disappeared amongst the
clouds. La Paz estimated it to be perhaps 20 miles away, judging from the clouds involved; and he put its length at
perhaps 100-200 ft.
Discussion:
This observation is attributed by Menzel (Ref. 24, p. 29) to "some sort of horizontal mirage, perhaps one of a very
brilliant cloud shining like silver in the sunlight - a cloud that was itself invisible because of the darker clouds in the
foreground." As nearly as I am able to understand that explanation, it seems to be based an the notion that mirage-
refraction can neatly _superimpose_ the image of some distant object (here his "brilliant cloud") upon some nearer
object in the middle distance (here his "darker clouds"). That is a fallacious notion. If any optical distortions did here
bring into view some distant bright cloud, it would not be possible to receive along immediately adjacent optical
paths an image of the intermediate clouds. Furthermore, the extremely unstable lapse rates typical of the
southwestern desert areas under afternoon conditions produce inferior mirages, not superior mirages of the looming
type here invoked by Menzel. Rapid displacements, vertically and horizontally, are not typical of mirage
phenomena. Hence Menzel's explanations cannot be accepted for this sighting.