Venus, Earth and Mars all have active and changing atmospheres, important not least in determining whether each planet is suitable for life. Earth today is a vibrant blue planet, teeming with life, while Venus is hot enough to melt lead and has a toxic atmosphere, and Mars is frozen and dry, with no liquid water at the surface. But this has not always been the case. Over four billion years ago, Earth was not the most welcoming home for life to begin. In this talk Professor Stephen Lewis will discuss the role played by the weather and climate on each planet, how this is important for spacecraft exploration today and why understanding other planets can tell us more about the Earth. The talk will describe some of the science behind The Planets TV series, first shown on BBC 2 earlier this year.