Homogenization of the Milky Way

It is possible to speculate on the very distant future of advanced civilizations. We can imagine such societies in excellent harmony with their environments, their biology, and the vagaries of their politics, so that they enjoy extraordinarily long lifetimes. Communications would long have been established with many other such civilizations. The diffusion of knowledge, techniques, and points of view would occur at the velocity of light. In time, the diverse cultures of the Galaxy, involving a...