The Father of Viagra, and a man with an asteroid named after him!

Dr Chris Smith and the Naked Scientists answer your science questions. This week the Nobel prizewinner who made Viagra possible, a space science writer with his own asteroid, how fungi have evolved to give us beer and bread, and where AI will take us in the future. Plus a mystery sound to identify (we don't think you'll get it), and a fun quiz to test your mettle.