Archive: The Measurement of Time

Misha Glenny chooses the first of his archive picks - bringing back classic conversations from the In Our Time archive, every Monday.

Humans have tried to calculate, regulate, and measure time for thousands of years: from systems based on tracking sunrise and sunset, to the invention of increasingly precise mechanical alarm clocks and astrolabes.

In this archive episode, first released in March 2012, Melvyn Bragg and guests discuss the methods used to measure time throughout human history. Early civilisations used the movements of heavenly bodies to tell the time, but in the ancient world there were also sophisticated timekeeping devices such as water clocks. The development of mechanical clocks in Europe emerged in the medieval period, when monks used such devices to sound an alarm to signal it was the hour to pray, although these clocks did not tell them the time. For hundreds of years clocks were inaccurate and it proved hard to remedy the problems, let alone settle on a standard time that a whole country should follow. It was the advent of the railways that meant time finally became standardised in Britain during the mid-19th century, and in 1884 Greenwich became the prime meridian of the world. Atomic clocks now mark the passing of the days, hours, and minutes and they are capable of keeping time to a second in 15 million years.

With

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

Jonathan Betts

Senior Curator of Horology at the Royal Observatory, Greenwich

Producer: Natalia Fernandez

In Our Time is a BBC Studios production