Think of how big our universe is. All those stars reaching out far beyond what telescopes can see. We cannot hold the size of the universe in our minds. It is so much greater then what we know. Now think of parallel universes. Not only is our universe big, but there are other universes. Perhaps just the number of universes (not size) is higher then humans have ever counted. Take that number and multiply it by the size of one universe. We have infinity times infinity.