Re: potentially stupid question -- no, not really at all
Seems quite sensible.
However, as you hypothesized, gravitationally bound systems defeat the expansion. This means forces stronger than gravity -- the strong nuclear force, electromagnetic force -- stomp all over the cosmic expansion. No chance for our bodily molecules or atoms to take part.
I'd have to look it up to be sure, but I believe that clusters of galaxies, and even superclusters, are bound together by gravity such that the individual galaxies inside the cluster are not receding from each other.
Biting the hand that feeds IT
