Melvyn Bragg and guests discuss the German astronomer Johannes Kepler (1571 - 1630). Although he is overshadowed today by Isaac Newton and Galileo, he is considered by many to be one of the greatest scientists in history. The three laws of planetary motion Kepler developed transformed people's understanding of the Solar System and laid the foundations for the revolutionary ideas Isaac Newton produced later. Kepler is also thought to have written one of the first works of science fiction. However, he faced a number of challenges. He had to defend his mother from charges of witchcraft, he had few financial resources and his career suffered as a result of his Lutheran faith. With David Wootton Professor of History at the University of York

Ulinka Rublack Professor of Early Modern European History at the University of Cambridge and Fellow of St John's College

Adam Mosley Associate Professor in the Department of History at Swansea University

Producer: Victoria Brignell.