I don't see why travel times is such an issue.
Imagine that some alien planet sends out a spaceship that needs a million years to reach the next star. Once there, it establishes an outpost, and builds a new ship. The mother planet does likewise (after watching reruns of Family Guy for a million years). In a further million years, these two ships arrive at two new systems. Repeat.
In less than eighteen million years, there'll be an outpost at every star in the galaxy (except for some recently formed stars, and a few that will have gone supernova and blasted it's associated outpost to bits, but that's marginal).
Eighteen million years is, of course, well little on the galactic timescale. And this assuming pretty slow interstellar travel - in a million years, Voyager 1 will have reached 50-60 ly out, or some ten times the average distance between stars in this part of the galaxy.
So, if even one civilization in the galaxy has embarked on a such project, we should expect they've got an outpost in the Solar System.
Now, if that outpost would contact us, or be easily contactable, is a whole 'nother question.
Imagine that some alien planet sends out a spaceship that needs a million years to reach the next star. Once there, it establishes an outpost, and builds a new ship. The mother planet does likewise (after watching reruns of Family Guy for a million years). In a further million years, these two ships arrive at two new systems. Repeat.
In less than eighteen million years, there'll be an outpost at every star in the galaxy (except for some recently formed stars, and a few that will have gone supernova and blasted it's associated outpost to bits, but that's marginal).
Eighteen million years is, of course, well little on the galactic timescale. And this assuming pretty slow interstellar travel - in a million years, Voyager 1 will have reached 50-60 ly out, or some ten times the average distance between stars in this part of the galaxy.
So, if even one civilization in the galaxy has embarked on a such project, we should expect they've got an outpost in the Solar System.
Now, if that outpost would contact us, or be easily contactable, is a whole 'nother question.
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