The Sun is intrinsically linked with every aspect of our existence - from the energy we use, the light we see, the heat on our skin, to the creation of life itself. But what about its link with our own physiology? If our biology is set up to work in partnership with the Sun and affects everything from our sleep cycles to our immune system and our mental health - just where does the Sun fit in in an increasingly fast, and busy way of living so many of us are now accustomed to? Linda Geddes, Freelance science and medical journalist, ‘New Scientist’ consultant and author of 'Chasing the Sun: The New Science of Sunlight and How it Shapes Our Bodies and Minds' joins Jonathan to discuss.