Seattle, WashingtonMay 1952

Early on the morning of May 11, 1952, a bright blue object streaked across the sky over Seattle, Washington, exploded in a brilliant flash, and disappeared. The flash lit up the entire city and rattled windows across a wide area.

Multiple competent observers saw the event. Two Northwest Airlines pilots, Captain B.C. Carlson and Co-pilot Earl Perry, spotted it at about 8,000 feet as they prepared to land at Seattle-Tacoma International Airport. A weather observer at the airport control tower, Robert Wiley, noted the brilliant blue light in his log. An engineer named Don Lyman, standing at a window in his home, watched the flash and quickly grabbed his watch and compass to document what he saw. The object came down steeply from the southwest, traveled from south to north across the city, and detonated with a flash that was visible from 60 miles away. After the explosion, witnesses experienced a shock wave that shook buildings and rattled windows about two minutes later.

Two local astronomers examined reports of the event and concluded the object was a meteor, a chunk of rock from space pulled toward Earth by gravity. As it fell through the atmosphere, friction heated it to extreme temperatures, causing it to glow vivid blue and eventually break apart in the spectacular explosion residents witnessed. The astronomers said they were searching for fragments to confirm their finding. The Air Force noted that no radar installations in the Pacific Northwest picked up the object, which made sense if it was a meteor coming nearly straight down. The file indicated that none of the radar installations in the region detected the object, possibly because its near-vertical descent made it difficult for radar to track.

The Air Force's official evaluation of the case was unidentified. However, the case file indicates the conclusion was probably a meteor, pending confirmation from recovered fragments. The full case file, comprising 23 pages, is reproduced below as held by the National Archives.