Project Blue Book Case File
Terre Haute, IndianaMay 1957
Summary
On May 31, 1957, someone in Terre Haute, Indiana, looked up and saw an object shaped like a quarter moon, about the size of a basketball, colored light orange. It hung in the sky without moving for roughly five minutes. Then it simply vanished.
The observer had noticed thunderstorms in the area at the time. When the Air Force investigated, weather officers noted that the moon was setting in the direction and at the time the object disappeared. The investigators also found that a thunderstorm was actively forming over Terre Haute. An Air Force intelligence officer who reviewed the case suggested the object may have been a reflection of lightning.
The file itself contains detailed weather data from the time of the sighting, including temperature, wind speed, and cloud cover readings at various altitudes. The investigators documented overcast conditions, rain, and lightning in the area, all factors relevant to evaluating what the witness had seen.
The Air Force ultimately marked this case as "unknown," meaning the investigators could not definitively explain the sighting, even though natural explanations like atmospheric reflection seemed plausible.
The full case file, comprised of 16 pages as held by the National Archives, is reproduced below.
Reported location
Terre Haute, Indiana
Date of incident
May 1957
State / country
IN / US
Page count
16 scanned pages
USAF evaluation
unknown
Microfilm
T1206, Roll 27