The universe is not homogenous. It is “grainy”. In other words, there is a maximum number of divisions that one can make on an imaginary clock or an imaginary ruler. The smallest possible unit of time is about about 10 to the minus 43 seconds, whereas the smallest possible unit of length is about 10 to the minus 35 meters. These are called Planck time and Planck length respectively.
Our observations therefore are like a flickering motion picture which give the illusion of fluid motion. In reality, there are “gaps” in the motion which happen too quickly for us to see. What we are actually observing is a series of “stills”.
What this means for the universe is that there not an infinite number of possible configurations of particles. There are a limited number of particles, a limited number of places and a limited number of instants in which they can exist. The possible combinations are staggeringly huge but not limitless. Barring outside intervention, everything is not possible in this universe.
One theory of the multiverse is that for every possibility there exists a universe in which that possibility exists. I have often heard an infinite number of such universes postulated but because there are only a limited number of possibilities only a limited number of universes need exist.