Light

Light itself does close to nothing.
Light never does anything really when you get down to it
except to go , in a vacuum, from one place to the other.

It’s emitted by one atom or particle and absorbed by another.

And it never goes and get slowed down or gets reflected.

What reflection really is is the light goes down is absorbed by something which shakes it and that emits a new light which comes back.

Reflected light is really not the same photon coming back as went in. The photon from the source went into the glass; from the glass comes out a new photon.

- Richard Feynman