So where is everybody?
Welcome to the Fermi Paradox.
We have no answer to the Fermi Paradox — the question as to where all the other inhabitants of the universe are. The best we can do are possibilities.
There is an explanation which states that there are no signs of civilizations because there are no higher civilizations in existence.
The Fermi Paradox exists because just looking at the mathematics, which says there should be many thousands or even millions of higher civilizations, that at least one of them would be an exception to the rule and have life.
If there are no super-advanced civilizations and since the sums suggests that there are thousands of them in our own galaxy alone, something else must be going on.
Possibility — Higher civilizations are all around us but we’re too primitive to perceive them. Michio Kaku sums it up like this:
“Let’s say we have an anthill in the middle of the forest. And right next to the anthill, they’re building a ten-lane super-highway. And the question is “Would the ants be able to understand what a ten-lane super-highway is? Would the ants be able to understand the technology and the intentions of the beings building the highway next to them?”
Possibility — we’re unbelievably wrong about our reality. The universe may appear one way and be something else entirely, or maybe we’re the aliens and we were planted here as an experiment or as a form of fertiliser. Maybe as I was brought up to believe, we are all part of a computer simulation by some researcher from another world and other forms of life weren’t programmed into the simulation.
Possibility: It might be incredibly unusual for life to begin at all.