A far-flung planet, shrouded in mystery, was discovered by a fortunate accident 75 years ago. Yet. despite huge advances in astronomy and space travel, many aspects of Pluto still remain a mystery today. Sue Nelson talks to
Dr Jacqueline Mitton and Dr Alan Fitzsimmons about the planet. How did a little girl from Oxford come to choose its name? Will a mission to visit this world ever take off? And is there an elusive Planet X beyond Pluto still waiting to be discovered? Producer Michelle Martin