Originally posted by googlefudge
I'm rapidly moving towards the POV that there are no spacefaring intelligent species within billions of LY.
Basically the Fermi paradox.
It's just so easy for a species to colonise billions of galaxies in such a short time frame [compared to the
age of the universe] that the fact that we don't have visible aliens in our solar system [and every ot ...[text shortened]... ll over the place, but nothing complex/intelligent enough
to build technological civilisation.
The laws of physics may indeed limit velocities to under c. That would still be a viable undertaking for robots to convert planets to a given life form, designed by an advanced alien civilization.
The idea of where are they, could just be the universe is too young to do much beyond your own home galaxy.
Just because our instruments don't detect anything yet could just be the relatively primitive state of our technology.
It might turn out only one techie civilization happens in a given galaxy at one time.
Maybe we are the only high tech civilization in our galaxy.
There would not be much chance of seeing (with our level of tech) high level civilizations in say, even close galaxies like Andromeda or the Magellanic clouds, the latter 'only' a couple hundred thousand ly or less. Andromeda at about 2 million ly. I would think we would need resolution requiring effective size of mirrors the size of our solar system to have any kind of chance at seeing civilizations in Andromeda. And that is only the close galaxies.
When I say mirrors the size of the solar system, I mean of course separated mirrors using combining technology to get an effective resolution of the distance between the mirrors.
Right now that tech is only good for a few hundred meters separation, at least here on Earth but future tech could theoretically allow mirrors separated by millions of miles to be used as a single telescope.
Maybe only in a couple hundred years but it should happen eventually.
Even that might not be enough to detect high tech in Andromeda.