I was interviewed by Seth Shostak (minutes 15:45 to 23:00 of this show) on possible observational consequences of my game theory model of interstellar colonization. (Previous posts on this here, here, here.)
The bottom line is that even if an alien colonization wave once passed this way, our astronomical theory and observation abilities are probably still just too weak to see the telltale signs of such a wave.
Robin on the migrating aliens: http://hanson.gmu.edu/fillu...
It makes little sense to me. Colonists would continue to suck resources, and the beam them to the front using relays - or use them on R+D, and then beam the results to the front, I figure. They wouldn't just leave a low-entropy state behind.
What is your best guess for what kind of objects would constitute the oases in your model?