But in Earth-bound reality, traveling at the speed of light (299,792,458 meters per second, or 670,616,629 miles per hour, in a vacuum) in a clunky rocket is a physical impossibility.

When light changes color due to speed, we call it redshift or blueshift ... and Father Christmas need to travel to deliver ...

On its surface, entanglement allows particles to communicate over vast distances instantly, apparently violating the speed of light. But while ...

is. Light of frequency \(4.6\times 10^{14}Hz\) travels at a speed of \(1.24\times 10^{8}ms^{-1}\) in diamond. Calculate the refractive index of diamond for this colour of light.

The change in direction of a ray depends on the change in the speed of the light and can be used to calculate the refractive index. For the example above the refractive index \(n\) of the glass is ...