World UFO Day is celebrated annually on 2 July to commemorate the 1947 Roswell UFO Incident and to raise awareness of “the undoubted existence of UFOs” and to encourage governments to declassify their files on UFO sightings. It is also an opportunity for people to gather together and watch the skies for unidentified flying objects. The Oxford English Dictionary defines a UFO as “An unidentified flying object; a ‘flying saucer’.” The first published book to use the word was authored by Donald E. Keyhoe. The term “UFO” (or “UFOB”) was officially created in 1953 by the United States Air Force (USAF) to serve as a catch-all for all such reports. In its initial definition, the USAF stated that a “UFOB” was “any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object.” Accordingly, the term was initially restricted to that fraction of cases which remained unidentified after investigation, as the USAF was interested in potential national security reasons and/or “technical aspects”.
During the late 1940s and through the 1950s, UFOs were often referred to popularly as “flying saucers” or “flying discs”. The term UFO became more widespread during the 1950s, at first in technical literature, but later in popular use. UFOs garnered considerable interest during the Cold War, an era associated with a heightened concern for national security, and, more recently, in the 2010s, for unexplained reasons. Nevertheless, various studies have concluded that the phenomenon does not represent a threat to national security, nor does it contain anything worthy of scientific pursuit (e.g., 1951 Flying Saucer Working Party, 1953 CIA Robertson Panel, USAF Project Blue Book, Condon Committee).
The acronym “UFO” was coined by Captain Edward J. Ruppelt, who headed Project Blue Book, then the USAF’s official investigation of UFOs. He wrote, “Obviously the term ‘flying saucer’ is misleading when applied to objects of every conceivable shape and performance. For this reason the military prefers the more general, if less colorful, name: unidentified flying objects. UFO (pronounced Yoo-foe) for short.” Other phrases that were used officially and that predate the UFO acronym include “flying flapjack”, “flying disc”, “unexplained flying discs”, “unidentifiable object”, and “flying saucer”
The phrase “flying saucer” also gained widespread attention after the summer of 1947. When On June 24, a civilian pilot named Kenneth Arnold reported seeing nine objects flying in formation near Mount Rainier. Arnold timed the sighting and estimated the speed of discs to be over 1,200 mph (1,931 km/h). At the time, he claimed he described the objects flying in a saucer-like fashion, leading to newspaper accounts of “flying saucers” and “flying discs”. Consequently many people celebrate World UFO Day on 24 June, the anniversary of the sighting.
The term UFO came to be used to refer to claims of alien spacecraft but because of the public and media ridicule associated with the topic, some investigators prefer to use such terms as unidentified aerial phenomenon (or UAP) or anomalous phenomena, as in the title of the National Aviation Reporting Center on Anomalous Phenomena (NARCAP).
The Roswell UFO incident happened 2.July 1947, after a United States Air Force surveillance balloon crashed at a ranch near Roswell, New Mexico, prompting claims alleging the crash was of an extraterrestrial spaceship. After an initial spike of interest, the military reported that the crash was merely of a conventional weather balloon. Interest subsequently waned until the late 1970s when ufologists began promulgating a variety of increasingly elaborate conspiracy theories, claiming that one or more alien spacecraft had crash-landed, and that the extraterrestrial occupants had been recovered by the military who then engaged in a cover-up. In the 1990s, the US military published reports disclosing the true nature of the crashed Project Mogul balloon (that’s what the US military want you to believe). Nevertheless, the Roswell incident continues to be of interest in popular media, and conspiracy theories surrounding the event persist.