How long can computation continue in the universe? Current observational evidence suggests that the universe will expand forever. As it expands, the number of ops performed and the number of bits available within the horizon will continue to grow. Entropy will also increase, but—because as the universe gets bigger it takes longer and longer to reach thermal equilibrium—actual entropy will increase at a slower rate than maximum possible entropy. As a result, the number of calories of free energy available for consumption within the horizon will increase.
