I don't get why the commenters think this model requires some ultra-stable political organization or unified civilization with a millions-of-years-long agenda to colonize the galaxy.
The model says a colonized world is expected to send out a colony vessel, if it has a suitable target within ten light years and hasn't done so more than nine times total or at all in the previous hundred thousand years.
A hundred thousand years is a long damn time. That doesn't even imply that these sequential colony ships would be sent out by the same species, let alone by some eternally-enduring political order or according to some galaxy-spanning imperative that endures for millions of years.
That's more like, "Every hundred thousand years or so we can expect that some civilization that values expansion will arise, at a time when building an interstellar colony ship is technologically possible, and endure long enough to actually launch one before it collapses or gets destroyed by its neighbors."
I wouldn't even expect individuals descended from the same colony to recognize one another as the same species, if both were five or six colony-worlds removed from it via different lines of descent. They'd probably recognize that they were related somehow, but not even guess how recent the last common ancestor might be. And as for political continuity? That's just out the window.
And anyway, I would be thinking in terms of systems colonized rather than planets, because the vast majority would be in habitats not on planets.
So I think you wind up colonizing systems more-or-less by default whenever they pass by close enough that its (uncolonized) oort cloud intersects your (colonized) one and even just one or two, out of MILLIONS OR BILLIONS, of habitats in the intersecting volume expands out to one of these valuable unclaimed bodies, at a moment when it's nearby, overcoming whatever delta-vee separates them. So with a spacefaring culture that inhabits its star's oort cloud I'd expect *EVERY* star that wanders into close range, to wind up colonized. Even accidentally, if colonies are captured by the passing star.
The model says a colonized world is expected to send out a colony vessel, if it has a suitable target within ten light years and hasn't done so more than nine times total or at all in the previous hundred thousand years.
A hundred thousand years is a long damn time. That doesn't even imply that these sequential colony ships would be sent out by the same species, let alone by some eternally-enduring political order or according to some galaxy-spanning imperative that endures for millions of years.
That's more like, "Every hundred thousand years or so we can expect that some civilization that values expansion will arise, at a time when building an interstellar colony ship is technologically possible, and endure long enough to actually launch one before it collapses or gets destroyed by its neighbors."
I wouldn't even expect individuals descended from the same colony to recognize one another as the same species, if both were five or six colony-worlds removed from it via different lines of descent. They'd probably recognize that they were related somehow, but not even guess how recent the last common ancestor might be. And as for political continuity? That's just out the window.
And anyway, I would be thinking in terms of systems colonized rather than planets, because the vast majority would be in habitats not on planets.
So I think you wind up colonizing systems more-or-less by default whenever they pass by close enough that its (uncolonized) oort cloud intersects your (colonized) one and even just one or two, out of MILLIONS OR BILLIONS, of habitats in the intersecting volume expands out to one of these valuable unclaimed bodies, at a moment when it's nearby, overcoming whatever delta-vee separates them. So with a spacefaring culture that inhabits its star's oort cloud I'd expect *EVERY* star that wanders into close range, to wind up colonized. Even accidentally, if colonies are captured by the passing star.