It's my understanding that in a few billion years, clusters of galaxies won't be able to directly observe one another due to the expansion of spacetime overcoming gravity between those clusters. However, it is also my understanding that spacetime in the local gravity clusters is "less" expanded due to, well, the presence of powerful gravitational forces holding spacetime together locally.
Specifically, I'm wondering if perturbations in space-time due to gravity might be detectable by finding areas of perhaps "less expanded" spacetime along the edges of the gravitational local group of the local galaxy cluster?
Let's speak purely theoretically, and ask the question of whether or not there will be some kind of stored information that a perfect observer might glean from the rate of expansion of spacetime along the edges of the gravitational local group.
