Pluto at 90: how Clyde Tombaugh discovered a new world
The latest episode of Radio Astronomy marks 90 years since the discovery of Pluto
This episode we mark the 90th anniversary of Pluto's discovery by exploring the life of US astronomer Clyde Tombaugh, take a look at the Pluto's rise and fall as the 9th Solar System planet and answer the question Why is Pluto not a planet?
Plus, we examine a recent International Astronomical Union campaign that saw 112 countries around the world name newly-discovered exoplanets.
Iain Todd is BBC Sky at Night Magazine's Staff Writer. He fell in love with the night sky when he caught his first glimpse of Orion, aged 10.