[yor_on (OP)]

Think of two galaxies separating through the accelerating expansion. At some point the light not only should be redshifted into oblivion, it should also find itself without any possibility of ever reaching the other side, becoming a sort of 'event horizon'.

so what about gravity?

[Kryptid]

Gravitational influence travels at the speed of light, so I would expect the same to be true of gravity.

[Halc]

Gravitational influence travels at the speed of light, so I would expect the same to be true of gravity.

Changes in gravitational influence travel at light speed.  A field doesn't travel at all, so gravity of objects beyond the event horizon should in principle have an effect here, but it's balanced out in all directions, so not sure exactly what distinct effect one is expecting one way or the other.

As far as the light analogy in the OP, I can still see objects well beyond the event horizon, and always will be able to see them no matter how far away they get. Yes, they get indefinitely red shifted after a while, but never so far as to blink out entirely.

[yor_on (OP)]

Would it mean that you can call gravity frame dependent too? You can transform away a gravitational acceleration so it should be frame dependent, but what does it do to a 'objective universe'? I always though of gravity as a sort of three dimensional 'net' consisting of SpaceTime, which to me then imply that even when you can't measure it, aka it becoming a 'flat space', the 'net' still should be existent. You can think of that as if we took away a mass far away, the 'signal' of that event would be propagating through this 'flat space' too, if gravity is a sort of 'net' covering a universe, even when immeasurable. Or it doesn't?
 

If gravity is observer dependent, can there be situations where it doesn't exist? And what does it mean? Either you have some sort of objective description that covers it all, or you don't. It becomes actually about what a 'objective reality' means, doesn't it? When thinking of gravity as the only thing able to communicate everywhere, past a black hole f.ex.
=

what I mean is that if gravity is observer dependent, and observer dependencies are the only things existing, how do you get to a objective universe? It' can't be a illusion, because all of us share a same experience, and can agree on it? And what is real there, the dependencies or the objective description. I keep coming back to this one.