[b] according the the known facts the sun is in the centre of the solar system we know this because of the fact all the planets revolve around it and we have over whelming evidence to prove this.We also have overwhelming evidence to prove we have a centre in our milky way galaxy.....why is it so hard to find the centre of the universe?THE SAME ANALOGY CAN BE USED TO FIND THE CENTRE OF THE UNIVERSE BY USING THE COLOUR SHIFTS OF THE GALAXIES TO SEE THE DIRECTION OF THERE MOVEMENT AND MAP OUT WHETHER THERE IS A "CENTRE OF GRAVITY' WHERE ALL KNOWN CELESTIAL OBJECTS REVOLVE AROUND. Its most likely there are multiple universes within the existing one in a much larger universe ,otherwise it would be impossible for it to hold together. Similar to your ballon theory murmured in some opinions, however imagine a clown holding a whole bunch of little helium ballons at a street corner and each ballon is a little universe and the whole bunch would consist of the whole universe. these little ballons would be most likely be interconnected by "black holes" or "worm holes" to even the "pressure between the universes to keep them "constant" similar to tornadoes that balances out differential atmospheric forces. Which ballon would be the centre of the universe, the answer would be they would all have a centre of their own universes>