Meteorites and Moon Rocks
This week JOHN SNAGGE visits the Natural History Museum in South Kensington to look at the world's largest collection of meteorites - the only tangible objects to come to us from outer space. The largest in the museum weighs three-and-a-half tons and the oldest has remained unchanged for 4,600 million years. John also examines a piece of moon rock presented by President Nixon. Producer ROGER CLARK