The astrophysicist Professor Lisa Kaltenegger is like an explorer of old, but her voyage takes her far from earth, planet hunting across the universe. She is Director of the Carl Sagan Institute to Search for Life in the Cosmos at Cornell University, and in her new book Alien Earths she describes the very latest discoveries of exoplanets which are the best contenders for harbouring alien life. Claudia de Rham is Professor of Theoretical Physics at Imperial College London and in her book The Beauty of Falling she tells the story of gravity. From her personal experience of diving in the ocean and freefalling over the earth, to exploring the limits of Einstein’s general theory of relativity she seeks to understand both the feeling and the fundamental nature of gravity. If only all of physics could be so compelling! Professor Mark Fromhold is Head of Physics at Nottingham University and is campaigning for a change to the way pupils are taught, suggesting that quantum physics be incorporated into the curriculum. He argues that at present the subject is too earth-bound, and ‘dull as dishwater’. Producer: Katy Hickman