Alien invasion orspace invasion is a commonfeature in science fiction stories and films, in whichextraterrestrial lifeforms invade Earth to exterminate and supplant human life, enslave it, harvest people for food, steal the planet's resources, or destroy the planet altogether. It can be considered as a science-fiction subgenre of theinvasion literature, expanded byH. G. Wells's seminal alien invasion novelThe War of the Worlds, and is a type of 'first contact' science fiction.
Experts consider the prospects of an actual invasion of Earth by extraterrestrials to be extremely unlikely, due to the enormous cost in time and resources.[1]
In 1898, Wells publishedThe War of the Worlds, depicting the invasion ofVictorian England by Martians equipped with advanced weaponry. It is now seen as the seminal alien invasion story[2] and Wells is credited with establishing several extraterrestrial themes which were later greatly expanded by science fiction writers in the 20th century, including first contact and war between planets and their differing species. However, there were earlier published stories of aliens and alien invasion, such as the 1892 novelThe Germ Growers by Australian clergyman Robert Potter, which describes a covert invasion by aliens who take on the appearance of human beings and attempt to develop a virulent disease to assist in their plans for global conquest. Potter's novel was not widely read.[2]
Wells had already proposed another outcome for the alien invasion story inThe War of the Worlds. When the Narrator meets the artilleryman the second time, the artilleryman imagines a future where humanity, hiding underground in sewers and tunnels, conducts aguerrilla war, fighting against the Martians for generations to come, and eventually, after learning how to duplicate Martian weapon technology, destroys the invaders and takes back the Earth.[3]
Six weeks after publication of the novel,The Boston Post newspaper published another alien invasion story, an unauthorized sequel toThe War of the Worlds, which turned the tables on the invaders.Edison's Conquest of Mars was written byGarrett P. Serviss, who described the famous inventorThomas Edison leading a counterattack against the invaders on their home soil.[4] Though this is actually a sequel toFighters from Mars, a revised and unauthorised reprint ofWar of the Worlds, they both were first printed inThe Boston Post in 1898.[5]
The War of the Worlds was reprinted in theUnited States in 1927, byHugo Gernsback inAmazing Stories.John W. Campbell, another key editor of the era, and periodic short story writer, published several alien invasion stories in the 1930s. Many well-known science fiction writers were to follow, includingIsaac Asimov,Arthur C. Clarke,Clifford D. Simak, plusRobert A. Heinlein who wroteThe Puppet Masters in 1951.[6]
This is a familiar variation on the alien invasion theme. In the infiltration scenario, the invaders will typically take human form and can move freely throughout human society, even to the point of taking control of command positions. The purpose of this may either be to take over the entire world through infiltration (Invasion of the Body Snatchers), or as advanced scouts meant to "soften up" Earth in preparation for a full-scale invasion by the aliens' conventional military (First Wave). This type of invasion represented common fears of the American public during theCold War, particularly thefear of infiltration by communist agents.[7] TheReptilian conspiracy theory claims that covert alien infiltration is already happening.
This theme has also been explored in fiction on the rare occasion. With this type of story, the invaders, in a kind oflittle grey/green man's burden, colonize the planet in an effort tospread their culture and "civilize" the indigenous "barbaric" inhabitants or secretly watch and aid earthlings saving them from themselves. The former theme shares many traits with hostile occupation fiction, but the invaders tend to view the occupied peoples as students or equals rather than subjects and slaves. The latter theme of secret watcher is a paternalistic/maternalistic theme. In this fiction, the aliens intervene in human affairs to prevent them from destroying themselves, such asKlaatu andGort inThe Day the Earth Stood Still warning the leaders of Earth to abandon their warlike ways and join other space-faring civilizations else that they will destroy themselves or be destroyed by their interstellar union. Other examples of a beneficial alien invasion areGene Roddenberry's movieThe Questor Tapes (1974) and hisStar Trek episode "Assignment: Earth" (1968);Arthur C. Clarke'sChildhood's End,[8] the novel (later anime) seriesCrest of the Stars, the filmArrival (2016), andDavid Brin'sUplift Universe series of books.
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 storySentry (1954) (in which the "aliens" described are, at the end, explained to be humans), the video gamePhantasy Star II (1989),[9]The Martian Chronicles byRay Bradbury, the Imperium of Man in theWarhammer 40,000 universe,Invaders from Earth byRobert Silverberg,Ender's Game byOrson Scott Card, and the moviesBattle for Terra (2007),Planet 51 (2009), andAvatar (2009–present).
Seth Shostak, senior astronomer at theSearch for Extraterrestrial Intelligence (SETI) believes an alien invasion of Earth to be unlikely for several reasons. He believes that any resources available on Earth can be found on their home planet, or that it would be easier to locate or create it on their own. He also believes that, if alien life were to make contact with Earth, it would first be through robots rather than the aliens themselves.[10]David Morrison, Director of Space atNASA-Ames Research Center argues that first contact would be in the form of radio communication rather than visitation.[10]
Invasion films were common in the 1950s featuring a variety of aliens portrayed as superior to earthlings both in intelligence and technology. In these films, aliens represent what some Americans feared about the Soviets. Invaders, friends or enemies, and often with the help of robots, either come to warn earthlings or destroy them with superior technology. Sometimes, the invaders use the strategy of infiltration, taking over the minds of the people, making slaves of them or appropriating their bodies, thus making war unnecessary. In some instances, the aliens already had a similar appearance - inStar Trek, while officially made contact with Humanity in 2063, (and were not "invaders" - some were shipwreck survivors, others time-travelers, accompanied by at least one Human, from a future where their respective worlds were allies) no fewer than six Vulcans had spent some time on Earth, passing as Human simply by using hair or skullcaps to conceal their pointed ears.
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