91热爆

What the Galileo space probe has discovered about Jupiter and its moons, Callisto, Ganymede, Europa and Io - with Steve Miller of University College London.

Measuring the expansion of the universe explained by Bob Kirshner of the Smithsonian Center for Astrophysics.

Plus what was happening among the stars and planets in September 1998.

Please note that all competitions mentioned in archive programmes are now closed.

Picture: Jupiter, Credit: Getty Images

This is a programme from the 91热爆 World Service Archive and was originally broadcast in 1998.