h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

This may seem like a really stupid question, but that's never stopped me from asking before.

There is convincing evidence that the universe is not only expanding but accelerating it's expansion. However, within our local area (i.e. galaxy or galaxy cluster) we do not observe expanding space due to the larger effect of gravity at these relatively short distances.

My question: Is there any way for us to determine which of the following two hypotheses are definitely correct, 1)Our local volume is staying the same size but the surrounding universe is expanding, or 2)The surrounding universe is staying the same size but we & our local volume are shrinking?

(Quantum mechanics tell me that all of the "mass" within matter particles occupies ideal mathematical points or at least no more than a billionth of a billionth of the volume we normally refer to as a "atom", so that seems like enough "space" to keep shrinking into for a very long time. I'm guessing that my shrinking hypothesis would imply that all the other far away local volumes were also shrinking to have any chance of making sense. However, I wonder if it would require that all the other local-volumes must also be shrinking at the same rate. Would one local-volume that is shrinking at a faster rate than a second local-volume appear farther away to us?)

It might be quicker if you take your question to the Science Explained forum A4108330


lil xx