Huh. Now you know.
Seth Lloyd (MIT)
Merely by existing, all physical systems register information. And by evolving dynamically in time, they transform and process that information. The laws of physics determine the amount of information that a physical system can register (number of bits) and the number of elementary logic operations that a system can perform (number of ops). The universe is a physical system. This paper quantifies the amount of information that the universe can register and the number of elementary operations that it can have performed over its history. The universe can have performed no more than 10^120 ops on 10^90 bits.
Might take a little while for Moore’s Law to produce computers capable of competing with this, but once there a computer will be able to simulate the entire universe. within a few years after that, a universe-simulating computer will be as cheap as a laptop; a few years after that there’ll be an app for that.