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An extraterrestrial or alien is any extraterrestrial lifeform: a lifeform that did not originate on Earth. The word extraterrestrial means "outside Earth". The first published use of extraterrestrial as a noun occurred in 1956, during the Golden Age of Science Fiction.
The 2nd century writer of satires, Lucian, in his True History claims to have visited the Moon when his ship was sent up by a fountain, which was peopled and at war with the people of the Sun over colonisation of the Morning Star.
Modern times
The Barney and Betty Hill incident took place in 1961, when the couple claimed that they were abducted by aliens and subjected to invasive experiments. It was the first recorded claim of an Alien abduction, soon followed by others. The description of the aliens made by the Hills, with oversized heads, big eyes, pale grey skin and small noses captivated the public imagination and was later used by TV shows and films. This started the grey alien archetype. According to Wade Roush, science and technology writer, "The standard depiction of aliens at that point became the little grey man. So, when Steven Spielberg came along and made probably what are the two most influential movies about aliens – Close Encounters of the Third Kind, and ET the Extra-Terrestrial – the aliens and those movies were both basically variations on the 1950s and 1960s little green or little grey man image".
See also
Articles related to the phenomenon of extraterrestrials in fiction and popular culture:
Grewell, Greg (2001). "Colonizing the Universe: Science Fictions Then, Now, and in the (Imagined) Future". Rocky Mountain Review of Language and Literature. 55 (2): 25–47. doi:10.2307/1348255. JSTOR1348255. S2CID171048588.
Roth, Christopher F., "Ufology as Anthropology: Race, Extraterrestrials, and the Occult." In E.T. Culture: Anthropology in Outerspaces, ed. by Debbora Battaglia. Durham, N.C.: Duke University Press, 2005.
Sagan, Carl. 1996. The Demon-Haunted World: Science as a Candle in the Dark: chapter 4: "Aliens".