Do Photons Live Forever – The Immortal Particles of Light

A photon born in the core of a star the moment Earth formed could still be flying through space right now, unchanged, carrying the same energy it left with four and a half billion years ago. Its internal clock has not ticked once. Not a single second has passed for it. We're going to follow one of these particles from the instant of its birth, through a universe that tries everything it can to destroy it — walls, black holes, the stretching of space itself — and ask whether anything in physics can actually kill light. If this fascinates you, hit subscribe so you don't miss where this leads. Now, hold your breath. We begin.