Alien invasion

Lucky for us, kids have been training to ward off alien invaders since the 70's!

The woo is out there UFOlogy

Aliens did it...

Best Evidence: Top 10 UFO Sightings Alan O'Reilly Behold a Pale Horse Alex Jones (slovensky) Alex Jones R/Conspiracy

...and ran away

Mike Bara Nazca lines Yonaguni Monument Ancient Aliens Ancient astronauts Erich von Däniken v - t - e

“”If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans.

— Stephen Hawking on Discovery Channel's Into the Universe with Stephen Hawking

An alien invasion, or an act of aggression by extraterrestrials against Earth, is a common trope in science fiction. The motivation is typically conquest, as in H.G. Wells' novel The War of the Worlds, or biological assimilation, as in the 1956 film Invasion of the Body Snatchers.

Over at Wikipedia, however, the term also includes any non-military encounter between humans and extraterrestrials that occurs on Earth. Fear, rather than the more appropriate responses of curiosity or wonder, dominate the discussion, probably because conventional wisdom about any such encounter has been constructed from narratives of conquest and assimilation. Thus the encounter in Arthur C. Clarke's novel Childhood's End is described as an alien invasion story despite the absence of any military operations or even the presence of many aliens on Earth once they reveal themselves.

Unfortunately, in an effort to appeal to audiences unfamiliar with hard science fiction, alien invasion stories in popular television and film are often trapped in the handful (and shrinking number) of historical metaphors familiar to the general public.

Variants of this trope, more typical in literary works, include the aliens, not the humans, being the curb-stomped ones in one way or in another despite their seemingly superior technology, and/or the contact with humans being a shock for them due to cultural differences and/or deeply changing their culture.

Defense

“”Burn the bodies, lest they stand up again.

—Gemini Home Entertainment, World's Weirdest Animals

It is unclear both what the risk is of an alien invasion of Earth, and how best to avoid or defend against it. We have little idea how many worlds may contain alien life, how many of those will have developed interstellar travel, and how many of those will be nice. (Attempts to estimate this, such as the Drake equation, are little more than wild guesses.)

It has been proposed that the best solution is to keep as quiet as possible, and cancel projects such as SETI which attempt to contact aliens. Distinguished people such as Stephen Hawking, Elon Musk, and author David Brin have suggested this. On the other hand, we unavoidably send lots of radio signals into space, so stopping SETI won't help much.

Travis Taylor and Bob Boan, two defense and aerospace consultants, have published "An Introduction to Planetary Defense"; they suggested our only hope would be asymmetrical conflict, such as guerrilla warfare. Other people have suggested imaginative tactics including blowing up satellites to intentionally create a debris field that would damage incoming spacecraft (Kessler syndrome would help); attacking craft as they enter the earth's atmosphere when sensors will be overwhelmed by the enormous heat; or threatening to blow ourselves up unless the aliens go home (which requires some major assumptions about the aliens' motives).

Nick Pope, a journalist who worked for the British Ministry of Defence investigating reports of UFOs, has also produced a plan on how to repulse an alien invasion — for The Sun newspaper. He suggested attacking with conventional missiles and nuclear missiles; using energy pulses to disable equipment (the effects on Earth equipment would probably be severe); as well as possibly concocting a biological weapon (which would require advanced understanding of alien biology, but is no more implausible than in the film Independence Day when they create an alien computer virus).

Alternatively, in the event of an alien invasion, we could follow the example of H.G. Wells's The War of the Worlds and just sit around and wait till they succumb to earth diseases. This assumes they don't have super-advanced medicine or protective biological warfare suits.

Plan

Based on the previous references and other sources, we can compile the following plan for an alien invasion:

1. Hide and hope they go home
2. Appeal to their better nature/Star Trek fandom
3. Block arrival with debris field
4. Electromagnetic pulse weapons
5. Nuclear weapons
6. Hide/guerrilla warfare/terrorism/satirical artwork
7. Develop bioengineered virus or computer virus
8. Hide and hope they die of earth diseases/get bored/get transferred/withdraw due to arcane office politics/go home
9. Pray Hope they come when our technology has advanced enough for us to be able to fight them in more or less equal terms when they arrive (assuming they do not find weather patterns totally fucked up or nuked wastelands everywhere instead, of course)
10. If all the above fails, get plastered and ruin the planet as much as we can so they'll not be interested in it

Of course, all the above assumes that they will not go Exterminatus on us from the other side of the Solar System or even much farther away, way beyond the range of anything we can throw to them, before landing, in which case we're pretty much toast.

And assuming "they", rather than behaving like curious but culturally ignorant tourists, actually have aggressive tendencies. Just like humans. (Which would make them not particularly "alien".)

The bullshit

From time to time, some cranks using as proof texts as for example those written by Nostradamus or the Book of Revelation, or simply inventing it, will claim that aliens will invade us. Of course, the predicted date will come and go and the only thing that will have been left behind is (still more) ridiculousness for said woo-meisters.

Fake invasions

A conspiracy theory suggests that somebody (the US government in the example cited) is planning to whip up fear of an alien invasion or even stage a fake alien invasion in order to panic the earth's population; this was suggested by Return of Kings and Steven Greer, described as a "retired physician" and (spoiler alert!) forms part of the plot of the Watchmen comics and movie. Supposedly this would allow the government to increase military spending and impose new controls on the population. This is similar to ideas that terrorist attacks such as 9/11 or military actions like Pearl Harbor were false flag operations designed to justify pre-planned government actions.

There are, however, reasons why faking an alien threat would be even stupider than staging a terrorist attack. While fear of terrorism is well-established and people have general ideas how to respond to terrorists (impose security crackdowns, bomb them, launch wars, etc), fear of alien invasion is not going to provoke such a simple reaction. People are more likely to recognize it as a fake, or if it was really convincing, it could cause a major change in people's political and even religious views; the natural urge to kill terrorists isn't matched by an equal desire to kill aliens.

See also

• Existential risk