The short answer is this:
No matter which direction we look into space, the expansion of the universe is always going to be the same. This sounds kind of obvious until you realize that 13.72 billion light years one way, and the same distance another way are incommunicable, and they've been incommunicable ever since the universe was created - light cannot travel from one point of our obvservable universe to another because it would then have to travel at twice the speed of c. Because these incommunicable points in space are the same in an infinite series of characteristics, then it's fair to assume that these physics are NOT local.