Extraterrestrial invasion

Name(s): 
Invaders from outer space
Undue influence by extra-terrestrial aliens
Nature

The alien invasion or space invasion is a common feature in science fiction stories and film, in which extraterrestrial lifeforms invade the Earth either to exterminate and supplant human life, enslave it under an intense state, harvest people for food, steal the planet's resources, or destroy the planet altogether.

The invasion scenario has been used as an allegory for a protest against military hegemony and the societal ills of the time. H. G. Wells' novel The War of the Worlds extended the invasion literature that was already common when science fiction was first emerging as a genre.

Prospects of invasion tended to vary with the state of current affairs, and current perceptions of threat. Alien invasion was a common metaphor in United States science fiction during the Cold War, illustrating the fears of foreign (e.g. Soviet Union) occupation and nuclear devastation of the American people. Examples of these stories include the short story “The Liberation of Earth“ (1950) by William Tenn and the film The Invasion of the Body Snatchers (1956).

In the invasion trope, fictional aliens contacting Earth tend to either observe (sometimes using experiments) or invade, rather than help the population of Earth acquire the capacity to participate in interplanetary affairs. There are some notable exceptions, such as the alien-initiated first-contact scenarios in The Day the Earth Stood Still (1951), Star Trek: First Contact (1996) and Arrival (2016). A trope of the peaceful first-contact is humanity attaining a key technological threshold (e.g. nuclear weapons and space travel in The Day the Earth Stood Still or faster-than-light travel in First Contact), justifying their initiation into a broader community of intelligent species.

A similar trope depicts humans in the role of the "alien" invaders, where humans are the ones invading or attacking extraterrestrial lifeforms. Examples include the short story Sentry (1954) (in which the "aliens" described are, at the end, explained to be humans), the video game Phantasy Star II (1989), The Martian Chronicles by Ray Bradbury, the Imperium of Man in the Warhammer 40,000 universe, Invaders from Earth by Robert Silverberg, Ender's Game, the movies Battle for Terra (2007), Planet 51 (2009), Avatar (2009) and Mars Needs Moms (2011).

As well as being a subgenre of science fiction, alien invasions are also considered to be a subgenre of invasion literature, which also includes fictional depictions of humans invaded by other humans (for example, a fictional invasion of England by a hostile France strongly influenced Wells' depiction of a Martian invasion).

Academics consider the prospects of an actual invasion of Earth by extraterrestrials to be unlikely, as Earth does not have any resources that could not be obtained by aliens elsewhere, among other reasons.

Source: Wikipedia

Claim 
One of the most dangerous consequences of the current space programme and the despatch of space craft to other planets is that it provokes the invasion of Earth by extra-terrestrials. Some UFOs are alleged to be associated with such invasions. It is believed that some have been shot down, although this information remains classified.
Broader 
Aggravated by 
Type 
(F) Fuzzy exceptional problems