For the last four years, a group of astronomers working with the giant radio telescope in Puerto Rico has been studying the behaviour of a pair of stars 15,000 light years away. Last month they published their findings which appear to offer the strongest support so far for Einstein's General Theory of Relativity.
The head of the group, Professor Joseph Taylor , of the University of Massachusetts, describes the experimental work, and discusses with John Mad dox its significance for our understanding of gravity, space and time. Producer GEOFF DEEHAN