Kenneth Albert Arnold (1915-1984) — businessman, private pilot with 4,000+ hours, Eagle Scout, Idaho politician. June 24, 1947, ~3:00pm: Flying a CallAir A-2 near Mount Rainier, Washington, on a detour to search for a downed USMC C-46 transport plane (offering a $5,000 reward). At 9,200 feet altitude, he saw a sudden bright flash, then nine shiny metallic objects flying in a chain formation past Mount Rainier southward toward Mount Adams. THE OBJECTS: Described as mostly circular (one crescent-shaped), approximately 50 feet in diameter each. Moving in an undulating, skipping motion. He timed them crossing the 50-mile stretch from Rainier to Adams: 1 minute, 42 seconds. Calculated speed: over 1,700 mph. The sound barrier had not yet been broken (Chuck Yeager: October 14, 1947 — four months later). TWO CORROBORATING WITNESSES: Washington State Forest Service lookout at Diamond Gap saw “flashes” at 3:00pm over Mount Rainier at exactly the same time. Sidney B. Gallagher saw nine shiny discs at the same time. “FLYING SAUCER” ORIGIN: Arnold described the objects’ motion as “like a saucer would if you skip it across water” — referring to their movement, not their shape. Newspaper reporters misquoted the East Oregonian interview and described the objects as saucer-shaped. The term “flying saucer” was born from this misquotation. AFTERMATH: Arnold’s story went nationwide via AP on June 26, 1947. Within weeks, hundreds of similar reports flooded in from across the US and worldwide. July 4 corroboration: United Airlines crew over Idaho saw 5-9 disc-like objects for 10-15 minutes. July 8, 1947: The Roswell “flying disc” was announced — within two weeks of Arnold’s report. The US Air Force launched Project Sign (1948) → Project Grudge (1949) → Project Blue Book (1952-1969). Arnold’s sighting is the opening event of the modern UAP institutional era.