The explanation as to why galaxies like the Milky Way and Andromeda are not expanding away from each other is that they are gravitationally bound, and the expansion at that small scale is not really apparent anyway. My question is purely hypothetical. What if you had a measuring stick that could extend to great length far enough where the expansion of space were significant. Would the atoms in the stick be electrically bound? In other words, does my measuring stick actually get longer because the space it is occupying is expanding, or does it 'slip' by the expansion because of the more predominant electrical forces holding the atoms together the same way gravitationally bound objects do at smaller scales? If the electrical force wins, and the measuring stick's length doesn't actually change, then what is it exactly that is expanding? If space itself is what is expanding, then it seems to me that a measuring stick occupying some space that is expanding should physically occupy more space (get longer), but this doesn't happen with gravitationally bound objects.