Here’s the Bestest Ever paragraph you’ll read in a physics journal article (physical review letters) with an awesome title to boot: “Computational capacity of the universe”
What is the universe computing? In the current matter-dominated universe most of the known energy is locked up in the mass of baryons. If one chooses to regard the universe as performing a computation, most of the elementary operations in that computation consists of protons, neutrons (and their constituent quarks and gluons), electrons and photons moving from place to place and interacting with each other according to the basic laws of physics. In other words, to the extent that most of the universe is performing acomputation, it is ‘computing’ its own dynamical evolution.