Seymour L. Hess's Flagstaff Disk Sighting

In 1950, Seymour Hess was a meteorologist with his eyes on another planet. He had come to Lowell Observatory in 1948 to observe Mars for his dissertation, and he was now working on planetary atmospheres at the observatory on Mars Hill, above Flagstaff, Arizona. He was a founding member of the meteorology department at Florida State University. Decades later he headed the meteorology team for the Viking Mars landers. On July 21, 1976, he issued the first weather report from another planet.

Saturday, May 20, 1950. Between 12:15 and 12:20 p.m. Hess was on the observatory grounds when he saw a bright object moving across the sky. A bright disk, cutting through clouds. He had time to send his son for binoculars.

Through the four-power glasses it looked at first "like a parachute." Hess thought it might be "just the section of one-half of a spherical object," one half lit and the other in shadow. James E. McDonald later described it as "somewhat like a tipped parachute" moving from southeast to northwest. It had no wings and no propellers. Hess neither saw nor heard any sign of an engine.

There was a small cumulus cloud in the northwest. As the object passed between Hess and that cloud, it appeared dark. It passed directly in front of the cloud before disappearing. In all, it had been in sight for about three minutes.

Hess did more than watch. He worked out a size of about 3 to 5 feet from the object's elevation and how large it looked through the binoculars. The clouds were drifting at right angles to its path, and from them he judged its speed at about 100 miles per hour, possibly up to 200. Using meteorological data, he put the cloud bases at 12,000 feet above the terrain.

The Weather Bureau's visual estimate was 6,000 feet. His verdict was firm. It "definitely was not an airplane."

On May 23, 1950, a United Press dispatch from Flagstaff ran under the headline "Astronomer says disc he saw wasn't plane." Williams Air Force Base disclaimed knowledge. No Project Blue Book file for the case has been located. NICAP later listed it in its 1950 chronology as a "powered" disc-like object seen from the grounds of Lowell Observatory by an astronomer and meteorologist.

On July 29, 1968, the atmospheric physicist James E. McDonald presented the case to the House Committee on Science and Astronautics at its Symposium on Unidentified Flying Objects. He used it as an example of UFOs reported by trained scientists. No hoax claim has ever been raised, and no formal explanation has been published. For a small, bright, silent object in daylight, a weather balloon is the obvious candidate. But a free balloon drifts with the wind, and Hess said the clouds moved at right angles to the object. McDonald's point was that Hess was a professional meteorologist. The figures leave one question open. An object 3 to 5 feet across, seen against clouds thousands of feet up, must either have been fairly close or have had its size worked out from an assumed distance.

The case survives in The UFO Evidence, in Richard L. Thompson's Alien Identities, in Stephen J. Spignesi's The UFO Book of Lists, and in lists of sightings by astronomers. What gives it weight is the witness. One day Hess would read the weather on Mars. In 1950, standing over Flagstaff, he measured what he saw and could not put a name to it.