May 26, 2021
(Bonus PDF) An unidentified flying object (UFO) is any aerial phenomenon that cannot immediately be identified or explained. Most UFOs are identified or investigated as conventional objects or phenomena. The term is widely used for claimed observations of extraterrestrial spacecraft and was coined as an anacronym by Project Blue Book project head Edward J. Ruppelt. Another widely used term for the phenomenon is "flying saucer."
Studies and investigations have been conducted by various governments worldwide, along with private individuals and organizations. In the United States, studies began in the late 1940s and have included Project Grudge, Project Sign, and Project Blue Book. The latter was ended in 1969-70 after the Condon Committee officially concluded that the subject failed to merit further study. However, an unpublicized study named the Advanced Aerospace Threat Identification Program was funded by the U.S. government from 2007-2012, and a successor program named the Unidentified Aerial Phenomena Task Force is currently operational.
Unidentified lights and flying objects have been reported in the skies for much of human history. Skeptics including various scientists, and organizations such as the Committee for Skeptical Inquiry, state that the entire topic can be explained as conventional objects or phenomena, while Ufologists suggest various unproven theories. Public polling indicates a considerable portion of the U.S. population feels that their government is withholding information on the subject.
The topic of UFOs has been, and is currently, popular in worldwide culture in fictional movies, television, and other media. UFO reports are also the subject of continuing debate and news reporting.