Philadelphia, Penn., August 1947 - Incident Number: 70August 1947

On the evening of August 6, 1947, multiple witnesses in Philadelphia reported seeing a bright, fast-moving object streak across the sky around 10:30 to 10:45 p.m. The object was white or bluish-white in color and left a thin trail of smoke or condensation in its path. Several witnesses heard a buzzing or hissing sound as it passed overhead.

A former Army Air Corps B-24 pilot who observed the object estimated it was traveling between 400 and 500 miles per hour at an altitude of 1,000 to 3,000 feet, moving from northeast to southwest. A retired Philadelphia police officer described the object as resembling a giant firecracker and said it passed completely out of view in a split second, leaving a fiery trail about 100 feet long. He was confident it was not a falling star and did not appear to be descending. Witnesses in different parts of the city, separated by roughly ten miles, reported observations that roughly corresponded to one another.

The FBI investigated the sighting by checking with Army and Naval Intelligence offices in Philadelphia to determine if any experimental aircraft or equipment tests were underway in the area. Both offices reported negative results. Investigators also looked into a chemical fire that had occurred at the Charles Lennig Chemical Company on August 6, but determined it could not have been visible from the locations where witnesses observed the object and did not match the reported flight path.

An Air Force analysis of this incident, reproduced with 15 pages of case materials below, categorized it as consistent with descriptions of relatively slow-moving meteors or fireballs, based on the speed, trail, sound, and color reported by witnesses. The full case file is reproduced below as held by the National Archives.