Simulating a/the universe, and simulating the universe at-or-above realtime are also two separate things. A non-realtime simulation would allow you certain sol

Simulating a/the universe, and simulating the universe at-or-above realtime are also two separate things. A non-realtime simulation would allow you certain solutions (such as perfectly recreating a past state of the current universe), but might not allow you to practically see a future state.