When you look up into the night sky, you can see thousands of stars shining. But you can't say how far away they are. Any star seems to be as far as any other and this led the ancient Greeks to believe that all the stars were the same distance away, stuck on a huge crystal sphere surrounding the Earth. Nowadays astronomers think differently, but how do they measure the distances to the stars?
Click on the name to find out more about each method:
PARALLAX - Two eyes are better than one.
VARIABLE STARS - Galactic buoys for navigating the heavens.
COLOUR - The Universe in full bloom.
THE EXPANDING UNIVERSE - The further they are, the faster they go