Extraterrestrial life in popular culture

In popular cultures, life forms--especially intelligent life forms, that are of extraterrestrial origin, i.e. not coming from the Earth--are referred to collectively as aliens, or sometimes visitors. This usage is clearly anthropocentric: when humans in fictional accounts accomplish interstellar travel and land on a planet elsewhere in the universe, the local inhabitants of these other planets are usually still referred to as "alien," even though they are the native life form and the humans are the intruders. In general they are seen as unfriendly life forms. This may be seen as a reversion to the classic meaning of "alien" (see foreigner) as referring to "other," in contrast to "us" in the context of the writer's frame of reference.
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