It takes 276 bits to enumerate every atom in the observable Universe so 512 bits should be enough for a single Universe given current known laws of physics. However, given the fact that we will be creating countless simulations of our own Universe, Q* says that we need 4096 bits.
Floating point numbers were invented as a compromise to allow for greater values at the cost of precision. Sure, they can be helpful in basic inaccurate simulations but absolutely don't work for proper accurate simulations.
