The Speed Of Light [Science; Ideas; Advanced Listening - mp3]

The Speed Of Light

This week we are discussing the speed of light. The medium most of you are listening by, radio waves, travel at the speed of light. And those of you closer to the radio transmitter will hear In Our Time fractionally before someone further away.
Here's another curious fact to ponder: For anybody listening who is aged 50, the light that reaches us from some of the stars in the galaxy left those stars before you were born.

Scientists and thinkers have been fascinated with the speed of light for millennia. Aristotle wrongly contended that the speed of light was infinite, but it was the 17th Century before serious attempts were made to measure its actual velocity – we now know that it’s 186,000 miles per second.

Then in 1905 Einstein’s Special Theory of Relativity predicted that nothing can travel faster than the speed of light. This then has dramatic effects on the nature of space and time. It’s been thought the speed of light is a constant in Nature, a kind of cosmic speed limit, now the scientists aren’t so sure.

John Barrow, Professor of Mathematical Sciences and Gresham Professor of Astronomy at Cambridge University

Iwan Morus, Senior Lecturer in the History of Science at The University of Wales, Aberystwyth

Jocelyn Bell Burnell, Visiting Professor of Astrophysics at Oxford University