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Science and the UFO phenomenon:

"Statement on Unidentified Flying Objects"

This statement has been submitted by Dr. James E. McDonald, Senior Physicist, Institute of Atmospheric Physics, and professor, Department of Meteorology, The University of Arizona, Tucson, Arizona, to the House Committee on Science and Astronautics at July 29, 1968, Symposium on Unidentified Flying Objects, Rayburn Bldg., Washington, D.C.

I created a table of content below; which was not part of the original scientific publication. The 56 pages publication is some 250Kb and I broke it in several files for acceptable web access speed.

Please go to the Science section of this website for more scientific papers by James E. McDonald and other scientists, plus comments and information regarding scientists' work and position about the UFO phenomenon.

Table of content

Dr. James E. McDonald.

Don't weather balloons and research balloons account for many UFOs?

Probably the most categorical statement ever made attributing UFO observations to balloons appeared in a _Look_ magazine article by Richard Wilson in February 1951, entitled, "A Nuclear Physicist Exposes Flying Saucers." Dr. Urner Liddel, then affiliated with the Navy cosmic ray research program using the large Skyhook balloons, was quoted as saying, "There is not a single reliable report of an observation (of a UFO) which is not attributable to the cosmic balloons." When one considers the large number of UFO reports already on record by 1951 in which reliable airlines pilots, military personnel, and other credible witnesses have observed unidentified objects wholly unlike a high-altitude, slowly drifting pear shaped Skyhook balloon, that assertion appears very curious. Nevertheless, that many persons have misidentified Skyhook balloons and even the smaller weather balloons used in routine meteorological practice is unquestioned. A Skyhook seen against the twilight sky with back illumination yields a strangely luminous, hovering object which many observers, especially if equipped with binoculars, were unprepared to identify correctly in the 1946-51 period when Skyhook operations were tied up with still-classified programs. To this extent, Liddel's point is reasonable; but his sweeping assertion fails to fit the facts, then or now.

Actually, in official case-evaluations, one finds Skyhook balloons invoked relatively infrequently compared with "weather balloons." But in many of the latter cases, the balloon hypothesis is strained beyond the breaking point. The official criterion used (Ref. 7, p. 135) is extremely loose:

"If an object is reported near a balloon launch site within an hour after the scheduled launch times, it is classed as a balloon."

with no specification of heights, shapes, distances, etc. Using such acriterion, it is easy to see why so many "balloon" explanations figure in theofficial summaries. There are even "balloon" UFOs whose speed, when inferred from the report, comes out to be supersonic! The tiny candles or flashlight bulbs hung on pilot balloons for night-tracking have been repeatedly made the basis for explanations of what witnesses described as huge luminous objects at close range. Within only days of this writing, I have checked out such a case near Tucson where four adult witnesses saw, on July 2, 1968, a half-moon-shaped orange-red object hovering for several minutes at what they estimated to be a few hundred feet above terrain and perhaps a few miles away over open desert. They watched it tip once, right itself, then accelerate and rise over a mountain range and pass off into the distance in some tens of seconds. Because a weather balloon had been released earlier (actually about an hour and forty-five minutes earlier) from the Tucson airport Weather Bureau station, the official explanation, published in the local press, was that the witnesses had seen a "weather balloon". A pilot balloon of the small type (30-gram) used in this instance rises at about 600 ft/min, the tiny light on it becomes invisible to the naked eye beyond about 10,000 ft slant-range, and the upper-level winds weren't even blowing toward the site in question. Also the angular size estimated for the observed reddish half-moon was about twice the lunar diameter, and some said about four times larger. A pilot balloon light would have to be within about 20-30 feet to appear this large. Yet such a case will enter the files (if even transmitted to higher echelons) as a "balloon", swelling the population of curious balloon-evaluations in official files.

1. Case 31. Ft. Monmouth, N.J., September 10, 1951:

It is clear from Ruppelt's discussions (Ref. 5) that a series of radar and visual sightings near Ft. Monmouth on 9/10/51 and the next day were of critical importance in affecting official handling of the UFO problem in the ensuing two-year period. Many details from the official file on these sightings are now available for scientific scrutiny (Ref. 7). Here, a sighting by two military airmen flying in a T-33 near Ft. Monmouth will be selected from that series of events because the sighting was eventually tagged as a weather balloon. As with any really significant UFO case, it would require far more space than can be used here to spell out adequately all relevant details, so a very truncated account must be employed. While flying at 20,000 ft from a Delaware to a Long Island airbase, the two men in the T-33 spotted an object "round and silver in color" which at one stage of the attempted intercept appeared flat. The T-33 was put into a descending turn to try to close on the object but the latter turned more tightly (the airmen stated) and passed rapidly eastward towards the coast of New Jersey and out to sea. A pair of weather balloons (probably radiosonde balloons but no information thereon given in the files) had been released from the Evans Signal Laboratory near Ft. Monmouth, and the official evaluation indicates that this is what the airmen saw.

However, it is stated that the balloons were released at 1112 EDST, and the sighting began at about 1135 EDST with the T-33 over Point Pleasant, N.J. In that elapsed time, a radiosonde balloon, inflated to rise at the 800-900 ft/min rate used for such devices, would have attained an altitude of about 17-18,000 ft, the analysis notes. From this point on, the official analysis seems to be built on erroneous inferences. The airmen said that, as they tried to turn on the object, it appeared to execute a 120-degree turn over Freehold, N.J., before speeding out over the Atlantic. But from the upper winds for that day, it is clear that the Ft. Monmouth balloon trajectory would have taken it to the northeast, and by 1135, it would have been about over the coast in the vicinity of Sea Bright. Hence, at no time in the interval involved could the line of sight from T-33 to balloon have intersected Freehold, which lies about 15 miles WSW of the balloon release-point. Instead, had the airmen some how seen the radiosonde balloon from Pt. Pleasant, it would have lain to about their N or NNE and would have stayed in about that sector until they passed it. Furthermore, the size of the balloon poses a serious difficulty for the official analysis. Assuming that it had expanded to a diameter of about 15 feet as it ascended to about the 18,000-ft level, it would have subtended an arc of only 0.6 min, as seen from the T-33 when the latter passed over Pt. Pleasant. This angular size is, for an unaided eye, much too small to fit the airmen's descriptions of what they tried to intercept. In a press interview (Ref. 40), the pilot, Wilbert S. Rogers of Columbia, Pa., said the object was "perfectly round and flat" and that the center of the disc was raised "about six feet" and that it appeared to be moving at an airspeed of the order of 900 mph. The entire reasoning on which the balloon evaluation is elaborated fails to fit readily established points in the official case-summary.


The possibility that a pilot can be misled by depth perception errors and Coordinate-reference errors to misconstrue a weather balloon as a fast-maneuvering object must always be kept in mind. But in the Ft. Monmouth instance, as in many others that could be discussed in detail, there is a very large gap between the balloon hypothesis and the facts. The basic sighting-report here is quite similar to many other daytime sightings by airborne observers who have seen unconventional disc-like objects pass near their aircraft.

2. Case 32. Odessa, Wash., December 10. 1952:

According to an official case-summary (Ref. 7, Rept. 10), two airmen in an F-94 "made visual and radar contact with a large, round white object larger than any known type of aircraft" near 1915 PST on 12/10/52 near Odessa. The radar operator in the F-94 had airborne radar contact with the object for 15 minutes, and during that same interval, ground radar was also tracking it. The summary states that "the object appeared to be level with the intercepting F-94 at 26,000 to 27,000 ft," and it is pointed out that "a dim reddish-white light came from the object as it hovered, reversed direction almost instantaneously and then disappeared." It is stated that the skies were clear above 3000 ft. The official evaluation of this incident is "Possible Balloon", although the report notes that no upper-air research balloon was known to be in the area on this date. The principal basis for calling it a balloon was the observers' description of "large, round and white and extremely large", and it was remarked that the instrument package on some balloon flights is capable of yielding a radar return.


To conclude that this was a "Possible Balloon" just on the basis of the description, "large, round and white and extremely large", and thereby to ignore the instantaneous course reversal and the inability of a 600-mph jet to close with it over a period of 15 minutes seems unreasonable. We may ignore questions of wind speeds at the altitude of the object and the F-94 because both would enjoy the same "tail wind effect". In 15 minutes, the F-94 would be capable of moving 150 miles relative to any balloon at its altitude. On the other hand, airborne radar sets of that period would scarcely detect a target of cross-section represented by the kinds of instrument packages hung on balloons of the Skyhook type, unless the aircraft were within something like 10 or 15 miles of it. Yet it is stated that the F-94 was pursuing it under radar contact for a time interval corresponding to an airpath ten times that distance. Clearly, categorizing this unknown as a "balloon" was incompatible with the reported details of the case.

On the other hand, there seems no reason to take seriously Menzel's evaluation of this Odessa F-94 sighting (Ref. 25, p. 62). Menzel evidently had the full file on this case, for he adds a few details beyond those in Ref. 7, details similar to those in Ruppelt's account of the case (Ref. 5):

"Dim reddish-white lights seemed to be coming from 'windows' and no trail or exhaust was visible. The pilot attempted to intercept but the object performed amazing feats -- did a chandelle in front to of the plane, rushed away, stopped, and then made for the aircraft on a collision course at incredible speed."

He indicates that after the pilot banked to avoid collision he could not again locate it visually, although another brief radar contact was obtained. Having recounted those and other sighting details, Menzel then offers his interpretation:

"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."

Now stars just above the viewer's horizon do scintillate and do undergo turbulent image-displacement, but one must consider quantitative matters. A refractive excursion of a stellar image through even a few minutes of arc would be an extremely large excursion. 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. A further quite unreasonable element of Menzel's explanation of the Odessa case is his easy assertion that the radar returns were anomalous results of the "atmospheric conditions". Aircraft flying at altitudes of 26,000 ft do not get ground returns on level flight as a result of propagation anomalies. These extreme forcings of explanations recur throughout Menzel's writings; one of their common denominators is lack of attention to relevant quantitative factors.

3. Case 33. Rosalia, Wash., February 6, 1953:

Another official case-summary of interest here is cited by Menzel (Ref. 25, p. 46). Keyhoe (Ref. 4), who studied the case-file on it much earlier, gives similar information, though in less detail. A B-36, bound for Spokane was over Rosalia, Wash., at 1:13 a.m. when, as Menzel describes it,

"the pilot ... sighted a round white light below him, circling and rising at a speed estimated at 150 to 200 knots as it proceeded on a southeast course."

Menzel states that the B-36

"made a sharp descending turn toward the light, which was in view for a period of three to five minutes."

The light was blinking, and Keyhoe mentions that the blink-interval was estimated at about 2 seconds.

Menzel concurs in the official evaluation of this as a "weather balloon", noting that a pilot balloon had been released at Fairchild AFB at 1:00 a.m., and remarking that the

"winds aloft at altitudes of 7,000 to 10,000 ft were from the northwest at a speed of about fifty knots."

He says that

"Computation showed that the existing winds would have carried the balloon to the southeast, and it would have been over Rosalia, which is 12.5 nautical miles southeast of Fairchild, in about fifteen minutes."

In fact, Rosalia lies 33 statute miles SSE of Fairchild, or about twice as far as Menzel indicates. The net drift of the balloon cannot be deduced simply from the winds in the 7-10,000-ft layer; and, in fact, an examination of the upper-wind data for that area on February 6 indicates that the winds at lower levels were blowing out of the southwest. The trajectory of the balloon would have taken it initially east-north-east, then east, and finally curving back to the southeast as it got up to near the 10,000-ft levels. By that time, it would have been already east of Spokane, nowhere near Rosalia.

The small light (candle or flashlight bulb) used on night pibal runs is almost invisible to the naked eye beyond a few miles' distance. (A 1-candle source at 3000 ft is equivalent to a star of about the first magnitude. At 6 miles, then, one finds that the same source equals the luminosity of a sixth-magnitude star, the limit of human vision under the most favorable conditions. For a pilot, looking out of a cockpit with slight inside glare to spot a 1-candle source against a dark back ground would require that the source be only a few miles away.) At some 30 miles, the B-36 pilot could not have seen the small light on a balloon east of Spokane.

Menzel states that

"the balloon carried white running lights which accounted for the blinking described, and the circling climb of the UFO is typical of a balloon's course."

Neither inference is supportable. The light used on pilot balloons is a steady source; only if one were right above it, with its random swing causing intermittent occultation, would one ever perceive blinking. But then, flying at B-36 speeds, the pilot would have swept over the sector of perceptible occultation in only a matter of seconds. Yet here the pilot watched it for a reported 3-5 minutes. Furthermore, "circling climb" cannot be called "typical of a balloon's course." The balloon trajectory is controlled by the ambient wind shears and only with unusually strong directional shears would a pilot flying a straight course perceive a pilot balloon to be "circling."

In all, there appear to be so many serious difficulties with the balloon explanation for the Rosalia sighting 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."

4. Case 34. Boston. Mass., June 1, 1954:

At 0930 EDST, a Paris-New York TWA Constellation was passing near Boston when the cockpit crew spotted "a large, white-colored disc-like object" overhead (Ref. 41). Capt. Charles J. Kratovil, copilot W. R. Davis, and flight engineer Harold Raney all watched it for a total time of 10 minutes as they flew on their own southwestward course to New York. They would occasionally lose it behind overlying clouds. Knowing that they were flying into headwinds, they concluded that it could not be any kind of balloon, so they radioed the Boston airport control tower, which informed him that jets were scrambled and saw the object, but could not close with it.

After landing in New York, Capt. Kratovil was informed that official spokesmen had attributed the sighting to a "weather balloon" released from Grenier AFB, in New Hampshire.


I am still in the process of trying to locate Kratovil to confirm sighting details; but the fact that four newspaper accounts for that day give the same information about the major points probably justifies acceptance of those points. From upper-wind data for that area and time, I have confirmed the presence of fairly strong flow from the WSW aloft, whence Kratovil's press comment, "If this was a weather balloon, it's the first time I ever saw one traveling against the wind," seems reasonable. The cruising speed of a Constellation is around 300 mph, so during the reported 10 minutes' duration of the crew's sighting, they moved about 50 miles relative to the air, so it would have been impossible for them to have kept a weather balloon in sight for this long. Furthermore, it was about 1.5 hours after scheduled balloon-release time, so that even a small balloon would have either burst or passed to altitudes too high to be visible. Finally, with flow out of the southwest sector from surface to above 20,000 ft, any balloon from Grenier AFB would have been carried along a trajectory nowhere near where the TWA crew spotted the "large, white-colored, disc-like object" overhead.

5. In my files are many other "balloon" cases from the past twenty years, cases that ought never have been so labeled, had the evaluators kept relevant quantitative points in mind. To ignore most of the salient features of a sighting in order to advance an easy "balloon" explanation is only one more of many different ways in which some very puzzling UFO observations have been shoved out of sight.

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