Summary: Melvyn Bragg and his guests discuss the measurement of time. Early civilisations used the movements of heavenly bodies to tell the time, then mechanical clocks emerged in Europe in the medieval period. For hundreds of years clocks were inaccurate but now atomic clocks are capable of keeping time to a second in 15 million years. Melvyn Bragg is joined by Kristen Lippincott, Former Director of the Royal Observatory, Greenwich; Jim Bennett, Director of the Museum of the History of Science at the University of Oxford and Jonathan Betts, Senior Curator of Horology at the Royal Observatory, Greenwich.
