> Or alternatively, perhaps we are in a simulation?

A relatively cheap one, considering that if this planet is the only one inhabited, the other star systems can be approximated and don't require full simulation.

Consider that time slows down when the speed is increased. This would be a good thing to do to restrict the computational requirements. And there's growing evidence that everything is quantized. Given that we probably can't measure anything smaller than a Planck length, that's the simulation resolution.

That's probably not what's going on (the simulation hypothesis could be the 'magnetism' of our era) but it is fun to think about.