Thanks, Donald. It’s a simple sounding question, but as you’re about to hear - the answer takes us deep into the strange world of quantum physics.

Marushka -A photon is a tiny packet of energy that makes up all forms of light from the electromagnetic spectrum; from long radio signals, to the warm glow of a candle, to the searing rays of a gamma burst. Unlike atoms or molecules, photons don’t have mass or internal structure.