Aliens : Science Asks: Is There Anyone Out There?

Do Aliens Exist? And if they do - what would they look like? Where would they live? Would they be conscious beings? And what would happen if they found us? These are the biggest questions we've ever asked - and here, Professor Jim Al-Khalili, theoretical physicist and host of BBC Radio Four's The Life Scientific, blasts off in search of answers. Coming with him are Martin Rees, Ian Stewart, Louisa Preston, Monica Grady, Sara Seager, Paul Davies and a crack team of scientists and experts who've m..