The Fermi Paradox, at its core, is the paradox between of the oldness and vastness of the universe, and the complete lack of any sign of observable life in it. The Mediocrity Principle tells us that we should assume humanity is fairly unremarkable, and the way life evolved on our planet should be assumed to be fairly typical until shown otherwise, but a quick look at the Drake Equation tells us that if we take the lower end of stars in the universe, the lower end of what part of them would be sun-like, and the lower end of how many of them would have a rocky planet with liquid water in the Cinderella zone where it is neither too hot nor too cold, there should be upwards of 100,000,000,000,000,000,000 Earth-like planets in the universe… or about 100 for every grain of sand on Earth. And most of them are incredibly, incredibly, incredibly much older than ours, and life did not take long to start arising on Earth after the planet formed… so if its as natural and common of a process as the Mediocrity Principle suggests, life should have existed in the galaxy for billions of years before Earth was formed.
From here, the Law of Large Numbers comes into effect, where we are forced to assume that even if a microscopically small percentage of a group would want to do something, the numbers are so vast that that tiny % still makes a large enough number it becomes an inevitability. And if a space-faring race emerged on one of those old-earths, and decided to colonize the galaxy, and sent out colony ships at an unfathomably slow rate of one every thousand years, and their colonies took another thousand years each to send out a colony ship of their own… the entire universe would have long ago been colonized by that entire race by now due to simple exponential growth.
Obviously, this hasn’t happened. So, if the universe is so old, and so vast… where are all the aliens, anyway? We should see them. In fact, we shouldn’t be able to miss them if we tried!
There are many theorized and proposed solution to this paradox, but far and away the dominant accepted line of scientific thought is School of Thought A – The Great Filter… although what the filter is is hotly debated and still studied. The idea goes that in order for us to notice alien life, that life needs to start existing, evolve, get intelligent, and survive long enough to get off their planet and start spreading or sending signals, and there are barriers any race would need to solve to get through that process and stay alive. A Great Filter is a barrier so severe and difficult that 99.999999% of species that try fail and go extinct.
The lines of thought generally go with one of these three – We’re Fast, We’re First, or We’re Fucked.
If we’re Fast, the idea is that the Great Filter was environment rather than developmental… that there is some evidence that until relatively recently the Universe was a much more hostile place to the development of life than its current state. This mostly takes account of how much more common Quasars and Gamma Ray Bursts worse until a few hundred million years ago, and supposed that life’s evolution in the universe really only started fairly recently, essentially greatly shortening the timescope. With the lag of lightspeed, that could explain our lack of evidence of alien life.
If we’re First, it means that the Great Filter is already behind us… and we aren’t mediocre at all. In fact… we probably ARE the only intelligent life in the Universe.
If we’re Fucked, it means that the Great Filter still is head of us, or at least that we aren’t passed it completely yet. Nuclear War, AI, Climate Destruction, the creation of Antimatter, and other such problems that seem inevitable to a growing society are often proposed filters still in humanity’s future as possible Great Filters. This chapter flirts with some of these ideas for the dead civilizations found by Talia Icarus in this chapter, but obviously intelligent alien life DOES exist, so we get to School of Thought B.
School of Thought B goes “Aliens exist, but we don’t see them because X.” The Kthid, in that way, are a solution to the Fermi Paradox… at least locally… any intelligent life that arises in the are draws their attention, and their society becomes too short lived to spread enough to become another civilization on their level. We don’t see alien life because any alien life that draws attention to itself gets wiped out… and by the time we are aware of the Kthid, its too late.
Now, this doesn’t explain the universe-wide lack of life having already colonized this galaxy before the Kthid arose… so clearly there is a combination of factors here… and clearly the Dark Star has something to do with it.
Note: This post lead to a very interesting discussion about the Fermi Paradox on discord. If this is your first encounter with the idea, I am NOT covering it in the depth it deserves here – I highly advise reading more up on it or watching some excellent Youtube video essays.