Sonoma, CaliforniaJanuary 1953

On January 10, 1953, at around 11:45 p.m., a retired Air Force colonel and a federal security officer observed an unusual object in the sky near Sonoma, California. The two men were standing on a knoll in the hills northwest of Sonoma Valley, about eight miles northwest of the town. The object appeared small, about the size of a pinhead held two feet from the eye, and silvery in color, possibly reflecting sunlight off an aircraft-type surface.

The object moved at extraordinary speed, estimated at four times faster than a jet aircraft like an F-80. As it traveled northwest, it made three 360-degree right turns in nine seconds, each taking two to three seconds to complete. The turns were remarkably tight, requiring only about one-eighteenth the space that a jet aircraft would need. The object then made a sharp 90-degree right turn, followed five seconds later by a 90-degree left turn that put it back on its original course. A sound accompanied the object, similar to a high-altitude jet, with no change in tone or volume during the maneuvers.

The object then slowed to almost a complete stop, accelerated back to high speed, and repeated this maneuver twice. Finally, it rose vertically and disappeared from view. The entire observation lasted between 60 and 75 seconds. The witnesses reported that the sun was setting to the west, visibility was good, and there was no ceiling (meaning clear skies overhead). The 25th Air Division reported no radar contacts with the object. No other aircraft were in the area at the time, and no trail or exhaust was observed.

The Air Force's analysis noted that a balloon was the only known object theoretically capable of such maneuvers, but the time factors and speed estimates ruled out that explanation. The case was marked unidentified. The full case file, consisting of 8 pages as held by the National Archives, is reproduced below.