One of the most commonly used tropes in science fiction is that of the notion of an alien invasion. Hundreds of variations on this theme have been written over the years, typically focusing on us having something that is useful enough for aliens to expend the time and energy in conquering earth. While all of this makes for a good story, it doesn’t prepare for a good reality. After all, this planet has been here for 4.5 billion years and does not appear to have ever been invaded. Why that is is anyone’s guess, but here are ten possible reasons why aliens might not invade earth.
10. The Galaxy has Nothing But Room.
Everywhere we look in the Milky Way we see star after star to the tune of billions and so far no one, other than our solar system, has ever been shown to be inhabited by a civilization. Some of them may yet be, but we see no evidence of Kardashev type III (aliens of extraordinary ability) galactic empires present in this, or any other galaxy. So far, we have yet to see even a Kardashev Type II civilization. This could change, but the one thing that can be said is that there appear to be millions of stars that are not being used for anything. Great nebulas rich in raw materials are not rare but seem only to be forming stars rather than being harvested by someone.
Often in science fiction, raw materials are used as a justification for invasion. However, in the grand scheme of things, there appears to be no one picking the low hanging fruit much less looking at relatively sparse sources of raw materials such as our star system
9. We Don’t Make for Good Slaves – Alien Invasions.
Another common theme found in science fiction alien invasions is a desire for slave labor. This is not without precedent, many human cultures have employed it. However, those cultures also were dealing with primitive technologies and required human labor. The problem is, natural human labor will someday go obsolete. It already is in our world as technological unemployment increasingly becomes a problem.
Simply put, robots can be better at it almost anything we do, if they become advanced enough. Any civilization in the galaxy capable of long-distance space travel and the technologies implied by it would likely have robotics so advanced that no biological labor at all would be needed. Moreover, besides, as long as you keep the technology under control and don’t go all crazy with artificial intelligence, mindless robots will never revolt. Humans would get every chance we could making us useless to the aliens
8. Our Planet is Fundamentally Useless.
Another common theme within invasion sci-fi is the idea that earth, or we, have something an alien civilization wants. This could be something like water or even information, and they invade to get it from us. Trouble is, we don’t have much of anything. Earth is nothing special. It’s made up of the same materials that we see out in the galaxy at large. Immense quantities of water exist in the universe, both in frozen and liquid form.
In fact, it appears to be common in our own solar system, you see it almost everywhere. It’s much the same for information. What could we tell the aliens that they didn’t already know or couldn’t learn on their own? The truth is, not much. About the only information, we have unique to ourselves is information about ourselves. It’s highly unlikely that an alien civilization would expend invasion level resources on finding out what a potato chip is.
7. We Are Very Likely Not Tasty.
Speaking of foods, take a look at your planet. Surrounding you are millions of species, from bacteria to plants to animals. Now, ask yourself. How many of them would you eat? Out of all life on this planet, we eat only a comparative handful of species. Many are fundamentally unpalatable, such as most plants, but many are outright poisonous causing anything from intestinal discomfort to death.
Now imagine an alien species with radically different biochemistry. They would have evolved on a world eating flora and fauna unique to that planet. It’s unlikely that anything here, or anything they might have, would be appealing to either species and there’s no guarantee that they even eat in the same way we do. Life here doesn’t always, so the idea of aliens eating us is a hard sell in much the same way as an oak tree munching on pineapples would be. Moreover, we might even be poisonous.
6. Our Genetics Aren’t Useful – Aliens
Another culturally pervasive notion is that of mating with an alien. From Captain Kirk’s Green lady to The Alien’s Xenomorph facehuggers using us as a reproductive resource, there are many takes on this idea. However, in reality, genetics doesn’t work that. The vast majority of species on earth can’t reproduce with each other despite being related; no jelly-fish bonobo hybrids are slithering. Moreover, while parasitic types of reproduction do occur, yay for the xenomorphs, that’s using a host as grounds for breeding, not reproduction with a mate.
Genetic compatibility with a species you have zero relation to, something genuinely alien from another world, would be very unlikely. However, even if there was compatibility, would there be an attraction? Kirk’s Green lady was a human in green makeup, remember. Alien life would be foreign and might be about as attractive as kissing a
However, there’s an even deeper problem hiding within this. Each day we learn more about genetics and DNA. While we don’t yet know everything, there will come a time when we have a full command of that science. It’s likely that an alien species capable of space travel would have that as well. Even if they didn’t have DNA of their own, which is unlikely, it’s still just a matter of chemistry. As a result, they could probably do whatever they wanted with genetics, possibly building DNA strands from the ground up to create any programmable creature they wish. If so, what use would they have for our natural and rather messy DNA?
5. The Human and the Ant
Ants usually go unnoticed. Unless they bother us, we pass by their dwellings and rarely pay them any mind. Even less do we stop and speak to them. Only a scientist studying ants would take a further interest, but also then they typically don’t plant a flag in the ant hill and declare themselves the new queen.
We have to consider that aliens may have no interest in us at all. They may be a billion years more advanced and messing around with us might be no different from junking your idea for a Caribbean cruise in favor of trekking to a plain in Africa to study one specific ant hill that you once saw a picture of that may or may not even still be there. In short, why would you invade an ant hill?
4. We’re More Interesting Alive Than Dead.
Alternatively, say they are interested. Say aliens are consummate scientists and historians interested in all aspects of alien cultures. This isn’t unreasonable; we certainly would be. Moreover, well, have to say it, an unknown ant hill would still be extremely interesting to us to the point that we would go to great lengths to study it. However, what we likely wouldn’t do is willfully exterminate it to review it. Such things happen on earth, but for very different reasons than scientific curiosity. As a result, the scholar aliens probably would not declare themselves our overlords and plant a flag in our cosmic ant hill, but instead, they might show up, enter orbit and tell us not to mind them, they want to watch us. With cameras everywhere. 24 hours a day. For millions of years.
3. It’s Not Worth It, Given the Distances.
The universe is enormous in a way that can’t be visualized regarding earth travel. You can say that Alpha Centauri is 25 trillion miles away, or about 40 trillion kilometers, but it’s hard to imagine just how far that is. If you shrink the scales down and make earth the size of a grain of sand, that star is still several thousand miles away. That’s still extremely close regarding the rest of the galaxy, so needless to say the distances involved for interstellar travel at sublight speeds are daunting and limiting.
This works the same whether you are an exploration craft or an alien invasion force. The logistics of moving around the assets you need on those distance scales and the time involved changing the equations for whether you would invade and conquer a planet. With enough distance, no world is worth it, especially when you consider that such gaps also prevent you from anything close to real-time reconnaissance until you get close by. In other words, what you saw as a primitive civilization from the deck of your fleet flagship 1500 years before you reached your target could well have developed advanced weaponry and technology by the time you were finally in proximity to invade. That uncertainty would make any such expensive undertakings likely not feasible.
2. We are Already Obviously and Flagrantly Dangerous.
Aliens film and sci-fi often depicts us as woefully unprepared for an alien invasion once it happens, but often the writers of that kind of sci-fi have to radically tone down or negate the weapons we do have, most typically giving the aliens shields that can withstand nuclear weapons. Little attention is paid to just how those shields function, and there isn’t much of a basis for such a strong yet invisible shield of this type in science.
But look at our weaponry in terms of sci-fi. If I were to tell you a story about an interstellar war where one side possessed weapons that had the effect of recreating a piece of a star right next to a space ship, you would assume that the ship would be destroyed. However, that’s more or less what a hydrogen bomb is, an advanced nuclear fusion device explicitly designed to kill something. While bigger weapons can be envisioned, the fact that we have H-bombs at all, and as a civilization achieved that technology so early means that anyone else in the galaxy probably has them too, and that may be enough to keep otherwise hostile alien cultures from messing with us or anyone else.
Moreover, there’s more reason to think this than merely blowing up the alien’s flagship. At sub-light speeds, we’re probably going to detect a massive invasion fleet well before it gets close. However, even if we don’t, if for some reason we don’t think we can target the aliens with a nuke or don’t have time, we can still target ourselves with a full global thermonuclear exchange and go out in a blaze of glory and poison the planet for the invaders. Such a thing could be arranged very quickly in this world, minutes, on the orders of only a handful of world leaders
1. Earth Itself Could Be Deadly Poisonous to Biological Aliens.
The biggest improbability in sci-fi regarding alien invasions is that aliens could stand around on earth without a spacesuit. You can’t do that anywhere in this solar system other than the planet. Same for any exoplanet we yet know of. Stand on Mars wearing little but a tee shirt you are soon dead. The surface of Venus is way worse. You can’t even breathe in Earth’s oceans without technology and fish likewise can’t usually breathe the atmosphere.
Moreover, even if you could breathe Mars’ atmosphere, you’re still dead from the sun’s unbridled radiation pretty quickly. Besides, then there is the much lower atmospheric pressure. The point is, the universe is most deadly to you anywhere except your home planet, and the same is likely right for aliens. However, it gets worse. Your world in the past has been hospitable to life itself, but deadly for you. Go into the far future, and it will be mortal again. You can only exist on your home planet under natural circumstances for so long.
While it’s hard to envision intelligent life existing on anything but oxygen, there are few chemical alternatives to run large brains, the oxygen levels of atmospheres could vary wildly, along with the other gases present. In short, Earth probably wouldn’t have the right mix for an alien to breathe, which would make this planet virtually useless for conquest and colonization.
So that’s ten reasons why real-world extraterrestrials would not invade earth. So you can sleep well tonight knowing that you probably won’t wake up to your new alien overlords tomorrow. Unfortunately, there is another side to this coin, so expect a future article detailing ten reasons aliens MIGHT invade.
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