What would happen if the entire universe would be reduced in size by several orders of magnitude. I mean not just the distances between the galaxies but also the size of every planet, every atom, every nucleus and so on. That also means the strength of all forces would have to become smaller. Would we notice any difference? The laws of quantum mechanics apply equally on all scales, what causes classical behavior is the large number of interactions and not the size. So no matter how small we make things, objects should still behave classically. But what about the planck length? What happens if the size of objects approaches that? Maybe if the universe shrinks in size the effect would essentially be the same as if the speed of light got reduced. At least thats what the equation for the planck length suggests.