Professor Brian Cox takes on the story of the force that sculpts the entire universe - gravity. It seems so familiar, and yet gravity is one of the strangest and most surprising forces in the universe. In a zero gravity flight, Brian considers how much of an effect gravity has had on the world around us. But gravity also acts over much greater distances. It is the great orchestrator of the cosmos.

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.