On Start the Week the sculptor Anish Kapoor talks to Andrew Marr about his fascination with voids and black holes, and his excitement at the latest technological advances in deepest black: vantablack. The astrophysicist Martin Ward explains his research into supermassive black holes and why we're finding more of them, while the solar physicist Lucie Green journeys to the centre of the sun where each photon takes hundreds of thousands of years to reach the surface, but just eight minutes to shine as light on the Earth. Writer Ann Wroe walks on the Downs to experience how light affects Nature, and she turns to the artists to meditate on the nature of light. Producer: Katy Hickman

Picture credit: Anish Kapoor.