Idaho, June 1947June 1947

In June 1947, a civilian observer in Idaho reported seeing a comet-shaped object in the sky that appeared to be stationary. The object was observed from the ground, and the witness reported seeing it at approximately 270 degrees azimuth (looking roughly west). The observation lasted an unspecified amount of time, and no photographs or physical evidence was collected.

The Air Force investigation noted that any astronomical explanation for the sighting would depend on knowing the exact time of the observation, which was not provided in the initial report. An unconfirmed statement suggested the sighting might have occurred at 3330 (3:30 p.m.), which would be consistent with a meteor train, a visible trail of dust left by a meteor burning up in the atmosphere. If instead the observation happened during early evening, shortly after sunset (which occurred around 2100 local time that day), then the witness likely saw either the planet Saturn or Mercury shining through thin cirrus clouds (high-altitude clouds made of ice crystals). A bright planet viewed through such clouds could easily give the impression of a comet-like object.

The Air Force concluded that the most probable explanation was astronomical in nature, most likely a bright planet observed in evening twilight. The full case file is reproduced below as held by the National Archives, spanning 8 pages.