Hawthorn, CaliforniaJuly 1957

On the evening of July 21, 1957, a man called a general building contractor in Inglewood, California, reported seeing strange objects in the sky near Los Angeles. He watched them with his family and neighbors from his backyard near Hawthorne, California. Over the course of several hours, he saw three separate objects. The first appeared around 8:30 p.m. and looked like a small sphere the size of a pea held at arm's length. It moved slowly eastward, then faded from sight around 8:40 p.m. A second, identical object appeared around 8:50 p.m. heading eastward from the western sky. At 9:07 p.m., it apparently exploded in a bright white and orange burst that the witness compared to a "miniature atom bomb explosion." No noise was heard, and no debris fell to the ground. A third object appeared at 9:30 p.m. and followed the same path, exploding around 9:45 p.m. When the witness looked through 10x50 binoculars, the objects appeared roughly 5 to 8 feet in diameter with a flickering flame or wick attached to the bottom. They had no sharp edges and made no sound even during the explosions.

The witness called the Los Angeles International Airport control tower during the sightings. A supervisor there searched the sky with binoculars and saw a bright flash of light approximately 20 degrees above the horizon to the east of the airport. Two tower operators also saw the flash, though they did not use binoculars. The supervisor described it as white in color, about the size of a pea held at arm's length, with no sharp edges and no sound. The object disappeared immediately after the flash.

The Air Force investigators conducted extensive follow-up work. They contacted weather services, military bases, observatories, balloon manufacturers, and local authorities throughout the Los Angeles area. The Weather Bureau at Santa Monica reported that a rawinsonde balloon (a weather balloon carrying instruments) had been released at 9:30 p.m. on July 21 from Santa Monica. It burst at a very high altitude around 9:40 p.m. The bureau noted that such balloons would not normally be visible in the evening unless they caught the sun's rays at extremely high altitudes. Investigators also confirmed that the U.S. Army Signal Corps had released weather balloons from Yuma, Arizona that day, but none drifted more than 15 miles from their launch site. The Hawthorne Fire Chief recalled a similar series of sightings in July or August of 1956 in the same area, which he believed were caused by balloons with flares attached, released as pranks.

The Air Force investigators concluded that the sightings were "probably balloons." The observers involved, including control tower supervisors, were considered reliable and well qualified. The file notes that radar checks at the time detected nothing unusual. The complete case file, totaling 32 pages, is reproduced below as held by the National Archives.