“The design of the universe…is very magnificent and shouldn’t be taken for granted.” -Charles W. Misner
One of the more puzzling aspects of our Universe is that, no matter which direction we look in, no matter how far away we check, its properties appear to be practically identical. This is surprising, since no signal can reach from one disconnected region to another, and yet the Universe behaves as if everything began from the same initial state. We refer to this as the horizon problem.
Before there was cosmic inflation, today’s leading solution to that problem (among others), there was the idea of a Mixmaster Universe, where a combination of oscillations and growth led to a Universe that got smoothed out by the dynamics of its evolution. Although it didn’t solve the horizon problem in details, the chaotic properties of a Mixmaster Universe provided physical and mathematical insights that are still useful today.