Seymour Hess sighting at Lowell Observatory, Flagstaff, 1950

1950. Seymour Hess was a young scientist who studied skies for a living. He was born in Brooklyn, trained in chemistry and meteorology, and had served as a lieutenant in the US Army Air Forces. Since 1948 he had been doing planetary meteorology research at Lowell Observatory, observing Mars. Later that year he would join the new meteorology department at Florida State University.

Accounts of the case describe him as "a meteorologist, astronomer, and an expert on planetary atmospheres."

Saturday, 20 May 1950. Between 12:15 and 12:20 p.m. Hess was on the grounds of Lowell Observatory, on Mars Hill above Flagstaff, when he saw a bright object in the sky. It was prominent. Even to the naked eye it showed some size. It looked at least partially spherical, and it was moving from the southeast to the northwest.

Then it passed between him and a small bright cumulus cloud in the northwest. In the open sky the object had looked bright. In front of the cloud it looked dark.

For roughly the last half of the time it was in view, Hess followed it through 4-power binoculars. At first it looked like a parachute tipped at an angle to the vertical. He noted that a sphere lit by the sun on one side and shadowed on the other could have produced the same appearance, and so could a disc. It had no wings. No propeller. No visible engine. He was quoted as saying it "definitely was not an airplane."

Hess worked from the object's elevation and the size it appeared in the binoculars. He estimated it was about 3 to 5 feet across and moving at 100 to 200 mph.

Hess wrote down his account within one hour. Newspapers carried the story, saying the object had looked "like a parachute" through binoculars. One version said he first spotted it in the southwestern skies. The papers also reported that Williams Air Force Base near Phoenix "disclaimed any knowledge of the object."

No official conclusion has been found. Research so far has not located a Project Blue Book file for Flagstaff on this date. In 1964, NICAP reprinted Hess's written statement in The UFO Evidence, edited by Richard Hall, in its section on sightings by scientists. The historian Loren E. Gross later covered the case in his UFOs: A History series.

No skeptic appears to have offered a specific explanation. Donald Menzel was the era's best-known scientific skeptic. He and Lyle Boyd thanked Hess in the acknowledgments of their 1963 book The World of Flying Saucers, but the parts of the book examined do not discuss his sighting.

The small size and the parachute shape could suggest a stray balloon or something carried by the wind. The witness weighed against that himself. In Aimé Michel's retelling, the object moved perpendicular to the cloud drift. Hess, a trained meteorologist, also ruled out birds and aircraft.

Later retellings changed the story. In 2000, The UFO Book of Lists described "a bright disk cutting through clouds." Hess had described one small cloud, with a dark shape crossing in front of it. His sighting came nine days after the famous photographs taken at McMinnville, Oregon, during a busy spring for reports.

Hess went on to lead the meteorology science team for the Viking landers. On 21 July 1976 he made the first weather report from another planet. Twenty six years earlier he had watched a small, unidentified object cross a cloud over Flagstaff.