Lexicon · Concept

UFO and UAP

The term UFO was introduced by the US Air Force in the 1950s. It originally denoted only the fact that something was unidentified, but in the public mind it became intertwined with the image of alien spacecraft. For this reason, official US usage today prefers the more neutral UAP, which covers not only aerial phenomena but also those observed underwater and in space.

The term UFO (unidentified flying object) was introduced by the US Air Force in the early 1950s; Edward Ruppelt, the first head of Project Blue Book, established it in place of “flying saucer” as a more neutral designation. It refers to celestial or aerial phenomena and objects that the observer cannot identify as a known aircraft, a natural phenomenon or another explainable object. In popular culture the concept has become closely intertwined with the idea of spacecraft of alien origin, although in its original meaning it refers only to the lack of identification and makes no claim about origin.

##The emergence of UAP

The abbreviation UAP was originally used for the expression Unidentified Aerial Phenomena, and it is not an American invention: the UK Ministry of Defence's Condign report, concluded in 2000, also referred to the phenomenon this way, and the UFO office of the French space agency uses the similar abbreviation PAN. The US Navy began using it in the late 2010s, and it became widely known through the UAP Task Force set up in 2020 and the intelligence community's 2021 UAP report. The US defense budget law passed in December 2022 expanded its meaning to the form Unidentified Anomalous Phenomena, so that in addition to aerial phenomena it also covers those observed underwater and in space, as well as so-called trans-medium objects moving between domains. This definition also underlies the work of AARO (All-domain Anomaly Resolution Office), established a few months earlier.

##Background to the change in terminology

The change in official usage was justified in part by the argument that the term UFO had become too closely associated with the extraterrestrial hypothesis in the public mind and had stigmatized serious scientific or military investigation of the subject. UAP, by contrast, is a more neutral, technical designation that does not presuppose an explanation for the observed phenomena.

The two terms are still often used interchangeably, although official US documents and congressional hearings now typically use the abbreviation UAP.

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