If the universe is expanding, and perhaps even in an accelerated way, it would seem natural that as space expanded some of the distant matter inside the observable universe would leak out to be unobservable. If that continued indefinitely, the extreme would be that only our Solar system would remain, and thereafter the Sun, the planets and the Moon would disappear, perhaps leaving us all the last guy on the block.
My first question is whether this is how the future is viewed, or is there a balancing effect of some kind?
Also, we read that “In a closed Universe, a light beam will eventually return to its starting point”
(www.opencourse.info › astronomy › introduction › 35.universe_structure)
but what if the “circular” path of the ray takes it onside the edge of the observable universe – surely it wouldn’t come back again?
My second question along this line is: If the observable amount of matter shrunk inside our observable universe – as a result of the expansion -- would it not reduce the differences between the different cosmological alternative and make it more or less Euclidean whatever its earlier state?