Do you ever find yourself just looking at the stars and wondering ?why?? Why haven?t evil intergalactic aliens come swooping down and killed us all in an orgy of Michael Bay explosions?? Yep, it?s one of the Big Questions in life and, like most questions so big they need to be capitalized, its logic can be dizzying. We all know there are something like 100 billion stars in the Milky Way. We?ve all seen the headlines about entire new solar systems being discovered, and figured out many or most of those stars must have planets. So where are all the wisecracking aliens?
The problem is known as the Fermi Paradox, after physicist Enrico Fermi. The basic idea is that the sheer number of planets, combined with the sheer amount of time our galaxy has been around (13 billion years) means thousands of civilizations as advanced or more advanced than us should have arisen by now. But we?ve never seen evidence of a single one. Here are 10 of the most interesting reasons why that might be.
10. We?re Completely Alone
Occam?s Razor states that the least complex solution to a problem is often the correct one. In the case of the Fermi Paradox, the least complicated answer is also the most existentially terrifying. The reason we?ve never seen any trace of alien life is because it simply doesn?t exist. In the near 14 billion years of our universe?s existence, intelligent life has only evolved in one place, at one time. Here, on Earth, in the last couple of million years. We?re utterly alone.
This melancholic solution is known as the ?Rare Earth Hypothesis.? The idea is that the Fermi Paradox is basically flawed. It doesn?t matter how many planets there are, or how much time has passed, because the creation of life is such a rare, once-in-a-universe event that the statistical likelihood of it ever arising is effectively zero. That life started on Earth is a freak accident as unlikely as you falling out an exploding airplane and managing to land unharmed in the hot tub at the Playboy mansion.
Broadly, there are three versions of this theory. One where life on Earth is completely unique; one where life is common, but multicellular life is unique to Earth; and one where complex life is common, but intelligent life is only on Earth. They still amount to the same thing: we?re never gonna meet the galactic neighbors because there aren?t any.
9. Other Intelligent Species Keep Killing Themselves Off
So, let?s assume we?re not particularly special, and that intelligent life is not uncommon. Let?s also assume that hundreds, maybe thousands of civilizations have reached our tech level before, and many have even surpassed it. Let?s even assume that there are other species out there right now, about 50-100 years ahead or behind us, plugging away to reach the stars. What would it mean that we?re unable to see them?
Here?s the bad news. It would probably mean that we?re completely screwed. One solution to the Fermi Paradox states that there?s an impassable barrier all life hits at a certain tech level. They call this the Great Filter.
The Great Filter?s big idea is that something conspires to destroy all civilizations before they go interstellar. It could be through nuclear war, or climate change, or the creation of hostile artificial intelligence. It could be any of million different things we can?t even begin to imagine. The point is that, at some stage ahead of where we are now, some mistake catches up with every single intelligent species and dooms them all. And we will soon be on the receiving end of it.
On the other hand, some find cause for optimism in the Great Filter. What if it exists, and we?ve already got past it? That would make us a one in a trillion fluke as a species, and mean the galaxy is now essentially ours.
8. We?re in a Giant Space Zoo
Imagine, for a moment, that you?re an uncontacted tribesman living deep in the heart of the Amazon. You?re vaguely aware there might be other races out there somewhere, and one of your peyote-addicted buddies even swears he saw a strange flying contraption in the sky. But you?ve never actually seen any non-tribe humans and have no real evidence for them.
Unknown to you, this is because the government of the country you aren?t even aware you?re living in has declared your stretch of wilderness a national reserve and forbidden anyone from trying to contact you. You live out your tribal life, never even suspecting that stuff like governments and financial services and low-cost air travel and motorcars and national borders and the internet might possibly exist. Well, who?s to say that doesn?t happen on a galactic level? More pertinently, who?s to say we?re not the tribe in this scenario?
Simply known as the ?Zoo Hypothesis,? this answer explains away the galaxy?s radio silence by suggesting we?ve been deliberately isolated. The most demeaning version has a bunch of sentient space squid (or whatever) watching us and laughing like we would at a chimp?s tea party. The less demeaning version has the galaxy?s aliens calling us noble savages, and watching movies where space Kevin Costner comes to live with us and humbly accept our simple ways.
7. Advanced Civilizations are Totally Over This Level of Reality
Maybe the idea of building up an interstellar or pan-galactic civilization is as embarrassingly backward to more advanced species as the feudal system is to us. What if truly advancing as a species isn?t all about getting Out There and seeing what?s what? What if it?s all about exploring the In Here; inside our own minds?
We don?t mean that in a drippy, New Age way. We mean there?s a good chance technology could improve so much leaving our home planet could come to seem as difficult and pointless as building a MacDonald?s on Mars. Take virtual reality. It?s kinda fun at the moment, but still new. Now take that tech forward by a hundred years, and imagine all the crazy, unbelievable stuff you could do with it. You?d never want to leave the house, right?
Well, now imagine that tech a thousand years in the future, or ten thousand. Imagine we?ve built a Dyson Sphere round our sun, and can use all its power to project a perfect, never-ending utopia directly into the minds of every human on Earth. A utopia where you can do anything, be anything, have whatever sex or adventures you like, and it feels like the experience lasts thousands of years instead of just one lifetime. It could be all our alien brethren are too busy living in tailor-made virtual heavens to ever bother contacting us.
6. We?re in a Simulation
We?ve got some bad news for you. There?s an excellent chance you?re living in a simulation. And we don?t mean a cool, Matrix-style simulation where you get to dodge bullets and rock a totally ’90s trench coat. We mean a perfect recreation of human life at this moment in time, that is generating the minds of everyone on Earth. Including you.
Simulation Theory assumes that tech will keep advancing until we reach a post-human level where programmers are so God-like, they?ll be able to create entire universes populated with digital civilizations so advanced in how they think and act they?ll essentially be alive. At that point, those post-humans would start using such simulations routinely, leading to the creation of quadrillions more digital souls than have ever existed in base reality. Assuming such tech is possible, we are now mathematically more likely to be inside a simulation than outside.
Well, that?s all very nice and mind-exploding, but what has it got to do with the Fermi Paradox? Possibly everything. In base reality, alien life may be so common that some far-future human has programed a simulation of human history that specifically contains no alien civilizations, just to see how it would have affected our development. We?re alone simply because no aliens have been coded into this particular simulation.
5. Aliens are Aware of Us and Will Kill Us Shortly
Here?s a chilling theory. What if it?s possible for intelligent life to evolve all the time, and advance to the stage where it spans the entire galaxy? What if this first happened millions, or even billions, of years ago? But, unfortunately, this first civilization to become pan-galactic was also hyper-rational to the point of coldness. They realized that allowing other civilizations to reach their level would put them in competition for resources. So they decided instead to exterminate them.
This scenario is all the more alarming, because the ?Superpredator? civilization it posits isn?t inherently aggressive. It?s just trying to preserve its advantage against competitors. This explains why we haven?t yet been killed; we?re still considered so laughably low-tech that the benefits to murdering us don?t yet justify the time or resources it would take. Especially when there?s every chance we?ll wind up killing ourselves in a nuclear war at some point anyway.
But when we reach some pre-determined tech level, that balance will tip, and the Superpredators will immediately destroy us. This could be why we?ve not yet seen aliens. The moment they go interstellar, or reach a stage when they could possibly communicate with us, they get annihilated. And there?s every reason to think reaching the arbitrary tech level that will trigger our destruction could happen very, very soon?
4. We?re Too Primitive (or Ignorant) to See the Aliens All Around Us
The first caveman to invent fire probably thought he was a pretty smart cookie. But what if, on the other side of the planet, a small colony of humans had existed that were at our current tech level? Our caveman dude would have had no way of knowing they were there, because all their signals would come in stuff like Wi-Fi and radio and texts that he was incapable of perceiving. He?d have just assumed fire made him king of the brainy castle.
The tech difference between the caveman and the modern humans would only be a million years or so. A million years in which only the last ten thousand years were marked by noticeable, century-on-century improvements. Now imagine there?s another tiny colony of post-humans on the planet, whose tech is a million or ten million years more advanced than the modern humans?. Would the modern humans notice the clues coming from the post-humans? hyperspace messaging service? Or would they be like the caveman, convinced they were the cleverest colony around?
Aliens could be all around us and communicating all the time, but they could be so ridiculously highly-advanced that we simply can?t detect them. If that?s the case, then we have no more chance of noticing them than we have of successfully teaching a June bug string theory.
3. We Live in the Middle of Nowhere
Remember Occam?s Razor? We kind of dismissed it after the number ten entry, but its search for the simplest solution has some bearing here. The reason we?ve never detected intelligent life near us could be that there?s no one living anywhere near us. Like a family of hillbillies drinking moonshine on a porch a hundred miles from the nearest small town, we could simply have chosen to build our home in a part of the galaxy that no one ever goes to.
There are endless reasons why this may be the case. We could live in a region that?s unusually hostile to life. It could be as Douglas Adams wrote in The Hitchhiker?s Guide to the Galaxy, and our western spiral arm of the Milky Way is just plain old unfashionable. Or it could be that everyone else has moved out of the inner systems, and migrated to the galactic ‘burbs. We might even have a reason for this: it could be the only way their society could survive.
Supercomputers already have to be kept in cooled environments. The sort of supercomputers a super-advanced species might build could generate so much intense heat waste that the only feasible option was to make their home on the galactic fringe, where it?s super cool all the time. This would explain why SETI have never detected alien signals. They tend to point inwards, into the galaxy, where there are more stars and, potentially, more civilizations. We could just be looking in completely the wrong place.
2. The Galaxy Has Only Just Become Capable of Housing Intelligent Life
Gamma ray bursts are scary. Super-intense beams of energy that are flung for trillions of miles across space, they unleash as much energy in under a minute as our sun will give off in its entire lifetime of 10 billion years. They appear from random points in space, and any planet or system that gets caught in their path effectively becomes sterilized. There?s even a chance that Earth?s first mass extinction event, the Ordovician extinction that took place nearly 500 million years ago, may have been caused by a gamma ray burst.
Gamma ray bursts in our galaxy are actually decreasing in frequency. Which raises an interesting hypothesis. What if the average time between parts of the galaxy being blasted by gamma rays has only just become long enough for intelligent life to form? Maybe there are no signs of advanced civilizations because we?re currently one of dozens that only cropped up now the gamma ray bursts have dropped us long enough to give us a shot at going interstellar.
That would mean there were probably thousands ? millions ? of planets out there that previously gave rise to intelligent life, only to see it completely wiped out when it was around stone age or even Renaissance or Victorian levels of tech. If true, it would mean dozens of civilizations will probably notice each other all at once in the near(ish) future; and that there are likely dead planets out there covered in fascinating ruins.
1. We?re Simply too Boring to Deal With
As we?ve seen, there are plenty of theories as to why we?ve never been contacted by alien civilizations. None are quite so ego-crushing as this one. The reason for our apparent aloneness could be that our neighbors are deliberately ignoring us. And not for altruistic reasons, like putting us in a galactic wildlife park. We could simply be too grotesque, or too warlike, or too upsetting, or even simply too boring for them to deal with.
While it?s possible alien life is similar to life on Earth, it?s also possible its completely different. It could be so different that our mere existence seems as nauseating to other civilizations as a race of giant, incestuous spider-cannibals that poop out their mouths and eat their own young would be to us. They might just find everything about us so horrifying, or barf-inducing, or morally repugnant that they refuse to even acknowledge us.
Then there?s the most depressing thought of all: we might simply be boring. Faced with all the other lower-tech aliens to explore, the advanced civilizations may have decided we?re basically a waste of time for whatever reason and deliberately ignored us. In other words, we?re the planetary equivalent of the nerdy guy at prom that none of the girls want to dance with. Sigh.