Just simulate the entire universe. It requires a computer the size of the universe.
There is one freely available, however, you will have to share it with a few other people. It's barely noticeable though because it's highly parallelizable.
Proprietary assholes. Maybe if they just made the source available we wouldn't have to spend countless man-millennia trying to reverse-engineer this thing.
Heh, actually this makes me think that Augmented Reality gaming is the way to go - like, proper real live-action quake overlaid onto RL environments. Then you only need to model the monsters, the environment's already done.
But I don't think we have the VR glasses for that one yet - I mean, Oculus is opaque.
And that's basically what we do already. When we throw global illumination and global fluid dynamics into the mix we quickly run up against the limitations of our machines.
Actually the problem is quite a bit simpler. You only have to simulate the observable universe, not the part that is outside our light cone, which is probably most of it. And the observable part makes it simpler still. You dont need to simulate planets more than a few hundred light years away, because they are not observable. It gives you time to upgrade your hardware before the next round of astronomical satellites goes up.
Its quite hard actually. By simulating the observable universe, I am not implying to draw the objects on screen. Its much more and computational astrophysicists are struggling like hell!
There is one freely available, however, you will have to share it with a few other people. It's barely noticeable though because it's highly parallelizable.