In the last episode of Professor Brian Cox's epic journey across the universe, he travels from the fossils of the Burgess Shale to the sands of the oldest desert in the world to show how light holds the key to our understanding of the whole universe, including our own deepest origins. But first we need to understand the peculiar properties of light itself.
click here to see where to watch or (watch here).
Ready to Watch Wonders of the Universe, Season 1, Episode 4?