system
Given the following post, respond as if you're commenting on Reddit:
human
Could an object get trapped in the expansion of space?

Okay, I have really no background in physics, let alone astrophysics, and the expansion of space kind of boggles my mind.  But I have a question:

If someone, say, future-humans, built a vessel that featured an essentially self-sustaining ecosystem (who knows if that's even at all feasible, maybe not) and fired it off into space on a trillion year journey toward another galaxy, would that vessel eventually get 'stranded' between galaxies, reaching a point where it would never be able to reach another galaxy or return home?

I guess my question could be summarized, "Are there dead zones where space is expanding such that objects could get stuck in it and never be able to reach other objects again?"
gpt
The expansion of the Universe is currently accelerating. Assuming it continues to do so - which depends on the exact mechanism causing the acceleration - then yes, it would be possible to travel so far away from the Milky Way that you could never return (or even send a signal back home), and you could also find regions such that you're (in the distant future) out of communication with *all* galaxies. The longer the acceleration continues, the shorter the distances are to those galaxies from which you won't be able to go home.

This is because in an accelerating universe, less and less of the cosmos becomes visible over time. In a sense, galaxies sufficiently far apart are expanding from each other so quickly that they'll "outrun" any light which one sends to the other.