I would imagine that we lack sufficient knowledge and space/resources/time to see effects on gravity in open space. The expansion of universe is instant and eternity depending. On relativity of the observer. So a space guy in space will most likely be able to measure due to the size relative to the entire reality format we’re in.
There's a theory that the universe will turn entirely black when its expansion will reach a point where all the galaxies will be so far apart that they will be too dim to detect, trillions of years in the future.
I guess that would depend on a great deal. I’d rate of expansion faster than speed of light. If not then only our observation would be able to see nothing. Due to atmosphere. But light continues to travel and stars far away still has billions of years left. Even if they’re not there anymore. It wouldn’t be observable to us for billions of years. What if rate of expansion, pulls harder accelerating expansion. Then leads to retraction back into nothingness. Infinite dimensions possibilities. Infinite density. Singularity I believe they call it. Then boom again. But I believe the accumulation of gravity would also accumulate as does mass. Trillions of years. I would imagine we wouldn’t be the same. Or alive still. Who knows.
I wouldn’t want to move forward up to that moment in time. These a just some shower thoughts lol
I’m happy with my life with my loved ones and that’s what matters.