Most of the sky is left unexplored. I think it’s premature to suggest we don’t see things. There are too many things to see in a single lifetime.
Most of the sky is left unexplored. I think it’s premature to suggest we don’t see things. There are too many things to see in a single lifetime.
But if there was a Kardashev type III civilization in the Milky Way, they would have had full control of our entire galaxy in a mere 200 million years or so. And we can be pretty sure that such a civilization doesn't actually exist. Which suggests that either advanced life is rare, or dies off long before it ever reaches such technological breadth.
Or this is merely sci-fi and it's physically impossible to build anything even close to such structures as Dyson spheres. There is no reason whatsoever to believe that just because we can conceive of something like that, it's actually possible to build it using real materials in real quantities with real amounts of available energy in a star system, and even less so to maintain these magical devices even if built.
you don't need to build a physical shell, a dyson swarm would get the job done.
Considering the distances between stars, we might not see civilization spreading as coherent empires but more like humans spreading through the islands of the pacific archipelago. Certainly the same species but also culturally seperated to develop on their own.
Unless faster than light travel or communication becomes avaliable, it might not even make sense to travel through the galaxy.
Maybe they have different motivations than humans because they are aliens.