Why Do the Planets Shine?

All the bright planets are now visible in the early morning sky. Some of them seem to outshine the stars, and yet they have no light of their own. They shine only by reflecting the light of the sun. The different ways in which they reflect the sunlight tell us a great deal about the planets themselves. Patrick Moore talks about the reflecting powers of the planets and what they can tell us with Dr Peter Cattermole of Sheffield University.