The Sky at Night — Episode 9: The Innermost Planet

You are watching the episode The Innermost Planet Mercury, the closest planet to the sun, is always difficult to study from earth, but it is at its best in the morning sky this month. So far the only space-probe to have bypassed it has been Mariner 10, more than 12 years ago. Patrick Moore has been to a conference in the USA in which all the information about Mercury has been summarised; tonight he explains what has been learned.