Why Would an Advanced Civilization Invade Earth?

Whenever we depict alien invasions of our planet, we seem to take it as a given that they would want to take it from us because, so far as we can tell, planets like this one are pretty rare things. (Though not as rare as we once thought.) But whenever Hollywood tries to depict the motivations behind an intelligent race trying to violently wrest our planet from our incompetent fingers, I think they tend to stumble into a number of pretty obvious fallacies.


  • The Oblivion Fallacy
    In Oblivion, an intelligent power comes to Earth because there is a specific resource here that it needs, and it therefore engages the human race in a decades-long war – obviously a massive drain on resources for both sides – that nearly ruins the planet. In Oblivion, this resource was hydrogen (taken from our water). This is a common theme for alien invasion flicks, though the resource varies. In Ender’s Game, it was water. In Cowboys & Aliens, it was gold. In Independence Day, it was everything. So on and so forth. The problem with this explanation, though, is that there are many easier ways of obtaining all of these resources elsewhere. Hydrogen, for instance, is the most common element in the universe. (Jupiter is about 90% hydrogen!) And while precious metals are certainly more difficult to come by, even our low-tech civilization is currently developing methods of mining asteroids for precious metals, as a single asteroid could easily contain more gold or platinum than has been mined from our planet in all of history. There certainly may be difficulties related to mining gas giants and asteroids, but I am sure that a civilization capable of interstellar migration would be able to handle it. At least, that would be easier than dealing with a race of pugnacious aborigines with fighter planes, the flu virus, and Apple computers. Water (or ice) is also plentiful in asteroids and uninhabited planets: Jupiter’s moon Europa is covered in it. Any alien race would probably have more of such resources in their own solar system than they could ever use. Even if they were to run out, Earth would probably be the last place in our solar system where they would look for said resources. The fact is that the only mineral resource our planet has that might be rare elsewhere would be heavy hydrocarbons like coal and crude oil (as they result from decayed organic matter), and I highly doubt that our alien enemies would be using spaceships powered by that kind of thing.


  • The Skyline Fallacy
    I know: most of you probably never saw this movie. It’s certainly not on my shortlist of alien invasion movies to watch. (It’s depressing.) Skyline recognizes that the one thing that makes our planet so valuable is our ability to produce life. And naturally, we assume that the most valuable piece of organic matter in this planet would be our brains. So the aliens want our brains. Apparently, our brains can be easily re-tasked to be used as the CPUs for semi-organic robots. But why would all of their technology come pre-wired to connect with the brains of creatures that emerged from an evolutionary path completely different from anything they know? And if we can grow meat artificially, couldn’t a much more advanced civilization grow brains artificially? Especially when their computing and robotics technology apparently depends on such brains? They could not have developed to such a point technologically by sourcing the key component of their technology “from the wild”.


  • The Keanu-Reeves-as-Alien-Jesus Fallacy
    In The Day the Earth Stood Still, Klaatu comes to save the world – even if that means killing all of us. In the end, as a merciful compromise, he keeps us from destroying our planet by rendering all of our technology inert. Thus, humans can happily return to their hunter-and-gatherer and simple-agrarian roots and live a spartan hippie life without producing massive amounts of carbon dioxide to destroy the world climate. The problem with this ending to the movie, however, is that it is laughably simplistic. If our technology were to stop functioning, that would include things like wastewater treatment, garbage removal, etc. Every city would become a highly polluted cesspool within a week. Governments would certainly collapse and be unable to enforce environmental law. Instead of coal, fuel oil, and natural gas, garbage and wood would be burned to keep us warm in the winter. The loss of modern farming methods would result in a significant loss in crop yields. The loss of modern transportation would make it impossible to get that food to the cities anyway. The result would be billions of people leaving the cities to carve out small farms for themselves. This would harm the environment exponentially more quickly than any human force has ever harmed the environment. So no…aliens are not going to come take our technology away to protect the environment. Anyway, the supposed merciful motivation of doing so instead of just killing us would be easy to forget with billions of us dying from starvation, disease, and exposure within just a few years. If they wanted to be merciful and achieve their original purposes, they would give us the advanced green technologies that they obviously have so we could stop burning fossil fuels without resorting to slash-and-burn farming and cannibalism.


  • The Battlefield Earth Fallacy
    I have actually only seen a few scenes from Battlefield Earth. I’m told that the greatest fallacy related to this movie was the initial idea that making it was a good idea. I do know, though, that an alien race comes and enslaves the human race, killing most of us and using the rest to help with the exploitation of the mineral resources that, as we have already established, would probably be easier for an alien race to collect closer to home. (In Transformers: Dark of the Moon, the aliens need us to build a massive piece of advanced technology.) But even if they did need slaves, would it not be easier to make lots of robots? (Especially if they are robots and therefore would not find it difficult to make dumbed-down versions of themselves?) What about mute drone laborers who are genetically engineered to be docile and not find ways to destroy you with primitive weapons?


  • The Fire in the Sky Fallacy
    This is an umbrella fallacy that takes various forms in various films and books. For instance, this may have been the implied motivation for the invasion depicted in Signs. It revolves around some sort of sexual impotence or evolutionary need on the part of the invaders, such that they need to commandeer our genome and reproductive systems for their own ends. (Because even if we hairless monkeys aren’t good at fighting, we’re at least good at making babies!) Again, though, this presupposes a very low level of biotech when compared with the high level of technology that would be required for interstellar travel on the massive scale.

So…why would an advanced race invade our planet? Some possibilities:

  • To fulfill an abstract, existential, or ideological purpose.
    A good example of this is The Host. They do not come to take our planet or our resources per se, but to partake of our experience. They only need Earth’s resources because they want to live like natives of Earth. They do this by taking control of our bodies within our natural environment and living, more or less, as we live. The result is a certain level of perceived spiritual and intellectual growth that cannot be explained in economic or logistic terms.
  • To have a good time.
    “But they don’t need to invade to have a good time here!” you may say. Well…think Predator. Maybe they just really like the idea of blasting carbon-based bipeds to pieces. If you think the price of intergalactic travel is too high for such cheap entertainment, remember what humans pay for the luxury of drinking coffee made from beans that have passed through the digestive system of a small arboreal mammal. An interstellar hunting trip seems pretty reasonable compared to $700 per kilogram for civet-poop coffee.
  • To save the planet.
    The scenario from The Day the Earth Stood Still was actually pretty rational up until the end. Save the planet from the humans – by killing all of the humans. Don’t try to be merciful by sending 7 billion people back to the dark ages, because that will be counter-productive. After eliminating the humans, the aliens would then proceed to turn the planet into a nature preserve.
  • To save us from ourselves.
    A less drastic version of The Day the Earth Stood Still – one in which the extraterrestrials establish a global fascist state and rule as a class of benevolent dictators. Kind of like I, Robot, only with aliens instead of robots. I don’t know of any books or films like this, but I think it would be interesting.
  • To farm.
    While they may not need our mineral resources, the life-supporting conditions here may be very valuable to them. They could grow food more efficiently here than in space stations or domed habitats elsewhere. With advanced energy technology, they could even irrigate the deserts and farm there. (This is assuming they are carbon-based life forms. If not, the necessary terraforming might prove too costly.)
  • To eliminate a threat.
    Maybe they have known about us for a while now, but they wanted to ignore us for as long as possible because we are the cosmic equivalent of the smelly kid who sits alone at lunch. But when we begin to develop faster-than-light travel and start looking to colonize other worlds, they suddenly feel the need to quash the spread of the interstellar vermin.

Naturally, I wouldn’t want to have to live through an alien invasion. But if they do come, they had better at least have rational reasons for doing so, or I’m not going to be pleased at all.

If I missed any important fallacies or logical reasons for invasion, feel free to list them here.