This can continue until the accelerating expansion of the universe places any other galaxies beyond our reach
If dark energy is constant, and if no-one artificially moves more galaxies together, then after 100 billion years, all that’s left in our Hubble volume is a merged Andromeda and Milky Way. On a supragalactic scale, the apparent abundance of the universe is somewhat illusory; all those galaxies we can see in the present are set up to fly apart so quickly that no-one gets to be emperor of more than a few of them at once.
It seems no-one has thought through the implications of this for intelligence in the universe. Intelligences may seek to migrate to naturally denser galactic clusters, though they then run the risk of competing with other migrants, depending on the frequency with which they arise in the universe. Intergalactic colonization is either about creating separate super-minds who will eventually pass completely beyond communication, or about trying to send some of the alien galactic mass back to the home galaxy, something which may require burning through the vast majority of the alien galaxy’s mass-energy (e.g. to propel a few billion stars back to the home system). There will be periods, lasting billions of years, in which some galaxies are beyond material reach, but visible and thus capable of communicating.
This cosmology of alien paperclip maximizers fighting over a universe of mutually receding galaxies, is not exactly proved by science, but it would be interesting to see it fleshed out.
If dark energy is constant, and if no-one artificially moves more galaxies together, then after 100 billion years, all that’s left in our Hubble volume is a merged Andromeda and Milky Way. On a supragalactic scale, the apparent abundance of the universe is somewhat illusory; all those galaxies we can see in the present are set up to fly apart so quickly that no-one gets to be emperor of more than a few of them at once.
It seems no-one has thought through the implications of this for intelligence in the universe. Intelligences may seek to migrate to naturally denser galactic clusters, though they then run the risk of competing with other migrants, depending on the frequency with which they arise in the universe. Intergalactic colonization is either about creating separate super-minds who will eventually pass completely beyond communication, or about trying to send some of the alien galactic mass back to the home galaxy, something which may require burning through the vast majority of the alien galaxy’s mass-energy (e.g. to propel a few billion stars back to the home system). There will be periods, lasting billions of years, in which some galaxies are beyond material reach, but visible and thus capable of communicating.
This cosmology of alien paperclip maximizers fighting over a universe of mutually receding galaxies, is not exactly proved by science, but it would be interesting to see it fleshed out.
Also see this timeline of the far future.