Fun fact: due to the uncertainty principle, light actually spreads out as a circular wave of probability from the Sun out through the solar system. It may or may not interact with something on the way - once it does, the probability wave function collapses into a certainty and is no longer spread out through the vast distances of space.

So this particular packet of light could be just about to interact with a rock on the Moon, when fate decides that it will instead end up drying your cum sock.