If the universe is a giant computer simulation, here's how many bits would be required to run it
Are we expected to take this title literally? If so, then it presupposes that there are alien intelligence(s) making these computers? If not, then the title simply suggests some sort of correspondence between a giant computer (to program the simulation) and the Universe itself. It also presupposes (or the authors do) that there are no philosophical problems relating to the Universe / observable universe(s).
Furthermore, it presupposes that this giant computer receives information (and/or transmits it) at FTL speed. Otherwise, how does the giant computer cope with locations inaccessible at c or below?
Would it not also need to track data on all the photons, neutrinos, and all the other stuff? Not to mention dark matter and energy. Is the computer part of the universe or is it outside, does it have to track the data points of itself?
Can it track data inside a black hole?
Has it successfully modeled chaos theory? Heisenberg may have something to say about this, tracking the position and velocity vectors. Will it’s observations affect the universe (Schrödinger)?
So, what happens when the computer crashes?
Heisenberg says you cannot exactly define both the location and velocity of any particle. Due to this limit, we can never exactly predict what a real life particle will do. The limitation does not preclude a simulation of a fictional particle. We simply assign probabilities to location and velocity and pick a set of numbers. It is fictional, so the final number has nothing it must agree with.