The best analogy to that of the expanding universe is a balloon getting blown up with an ant and multiple dots on the balloon’s surface. The ant can be seen as a 2D being, on a 2D universe expanding into a 3D space. The distance between any two spots grows at a faster rate the greater the distance between them. Both of these fact translate up to the real universe’s expansion also. For more complex details on the subject reading Owais Najam’s articles at The Brilliant Cosmos is recommended. The final key comparison to make is that for the spots on the balloon, there is no centre. Each spots moves away from each other spot and none can be considered a focused centre, not just due to relative motion but by an inherent fact about the universe model created. This fact, that wherever you go in the universe things generally stay the same, is an important concept for cosmological calculations.
Recently researchers from both University College London and Imperial College London have managed to prove that there is a 99.9992% chance that the universe is not isotropic. The came to conclusion by examining the cosmic background radiation data gathered by the Planck satellite to see if, when the branch of Einstein’s Field Equations that assume an irregular universe are applied, they match this data. This would also reveal if the universe was spinning about a point or had an even more irregular dynamic to it. Ultimately, this result is important as it revealed that main stream cosmology was once again secure in its assumptions. If these kinds of test are not carried out we may end up wasting fifty years on an endeavour that turns out to be a false goal.