2021-07-29, 01:46 PM (ISO 8601)
Bugbear in the Playground
Re: Properties of void outside the universe*?
As far as we can tell the rate of expansion is constant. So the absolute size of the visible universe - the distance from which a photon that originated at a given point would have had the time to reach us - will only ever increase. For that to change the rate of acceleration would have to increase, we'd wind up facing down a big rip scenario, and there's no evidence that that's the likely ultimate fate of our universe.
Originally Posted by halfeye
Of course the extra space created by the expansion of space is empty, boring space. And the increased distances push away matter that's far more interesting. So in the distant future when all the local galaxies combine into one super galaxy and all the other galaxies have been pushed out past the cosmic event horizon, it doesn't matter how far out a hypothetical photon could have started out in order to reach earth by that point. What would matter is that there wouldn't be any matter or other interesting stuff that could produce such photons, so the point would be moot.