We were reading Steven Hawking’s A Brief History of Time, and Simon asked: “If the speed of light is the same relative to any body, is it the same relative to other light? How fast is light relative to itself? Is it stationary or does it have the speed of light?” We tried to imagine what it feels like to be a ray of light. Simon thinks that to light (or to a photon), time doesn’t exist. Does that mean that to light (to a photon), there is no causality? (Like a photon doesn’t know what happened first and what happened later – whether it first left the star Betelgeuse (640 light years away from the Earth) and then reached the Earth or the other way around?
Another observation from two days ago: Simon says that the tunnel appearing in the mirror once two mirrors are placed opposite to each other grows linearly with respect to time but always remains finite. Within one second, if you stand 1m away from the mirror, you will get 299 792 458 mirrors in your tunnel (because that’s how many times light will travel back and force during one second) or 149 896229 (half the previous number) small mirrors reflected in the large mirror: