Gurnee, IllinoisSeptember 1960

On the night of September 1960, a resident of Gurnee, Illinois watched what he described as a bright, star-like object moving across the sky. The object appeared on the horizon at about 30 to 45 degrees above the horizon, then moved silently upward before beginning a slow descent toward the northwest. As the object descended toward the horizon, its color changed from white to red, then rose and orange. The witness said it disappeared below the horizon roughly straight west of his location.

The observer reported that the object was about the size of a medium-sized star and remained visible for approximately two hours. When he submitted a letter to the Air Force describing the sighting, officials responded by asking him to complete a detailed questionnaire. The Air Force later indicated that other observers in the area had reported similar phenomena at the same time.

The investigation included correspondence with the witness and efforts to gather additional testimony from other people who had watched the sky that evening. Officials noted reports had been received from people outside of Gurnee who had also noticed the object.

The Air Force concluded that the sighting was most likely atmospheric refraction, a phenomenon in which light from a star or planet bends as it passes through layers of air at different temperatures. The evaluation stated that the motion and appearance described by the witness were consistent with refraction effects, which can make celestial objects appear to move in ways that seem unusual but are not physically real.

The complete case file, consisting of 16 pages as held by the National Archives, is reproduced below.