Instead of its limits, you should consider the assumptions it is based on. Start with the photon. Wave or particle? Would that matter?

I know of better ways of explaining red shift and particle accelerators that have nothing to do with SR.

## Assumptions

Instead of its limits, you should consider the assumptions it is based on.

Start with the photon. Wave or particle? Would that matter?

I know of better ways of explaining red shift and particle accelerators that have nothing to do with SR.