Brian Greene came to speak at our university, and I'm left with a couple questions about dimensions and universes that maybe you guys can help me out with. I hope this is the correct topic to post these questions under: 1) Is the 4th dimension still considered by most people as Time? Where is this 4th dimension? Is it at the larger level (multiple universes at different times) or the smaller level (at each point in space there are multiple times)? 2) How is a 'parallel universe' created every time there is an opportunity for chance? 3) Is a parallel universe another dimension? Where are they located? On top of each other or next to each other? Do they have to do with time? 4) Brian Greene talked about a circular dimension at each point in the 3-D universe. Is that the 4th dimension? (Time?) Something else? Thanks!