In space, light will go on, and on, and on… In a windowless room, where does the light go when we switch it off? Light is a pretty simple beast. In lieu of any interference, it will go on, and on, and ...

Ever wonder how a mirror works? If you want to find the path that light takes when reflecting off a surface, you could use Fermat's Principle. This states something like this: The path that light ...