Blue Peter presenters Helen Skelton and Barney Harwood want to learn more about the solar system so they challenge scientists Helen Czerski and Jem Stansfield to find out more. They look at how to make telescopes and rockets, and use a toilet roll to measure the distances between planets.
In this animated adventure The Doctor and Martha Jones trek through space and time in a race against the galaxy's greatest despot, Balthazar, to follow a complex trail of clues to discover the location of the legendary lost spaceship, the Infinite, which, according to myth, can grant anybody their heart's desire.
