Interstellar travel has always seemed impossible - the realm of science fiction rather than reality. But that view is now changing. The team are joined by Jim al-Khalili to investigate if it will be possible to travel to the sun's nearest neighbouring star - Proxima Centauri - within our lifetimes. Recently, a discovery was made that suddenly gave us a powerful reason to want to travel to Proxima Centauri. An Earth-like planet was discovered in orbit around the star. That followed the announcement of Breakthrough Starshot - a project to develop the technology that could send a spacecraft to the nearest stars in just 20 years. Chris Lintott meets Guillem Anglade-Escude - the scientist behind the discovery of Proxima b - to reveal the observations that revealed the existence of the planet. Maggie Aderin-Pocock meets Dr Jo Barstow, an expert on planetary atmospheres to discover what we think conditions may be like on the planet. Jim al-Khalili investigates Breakthough Starshot.