Explore the fascinating history of light speed measurement and the quest to understand how light travels through space in this Royal Institution lecture. Delve into the work of renowned physicists from ancient Greeks to Einstein as they grappled with the concept of the mysterious 'aether' and searched for a frame of absolute rest in the universe. Learn about groundbreaking experiments, including the Transit of Venus, and the contributions of scientists like Hippolyte Fizeau, Leon Foucault, and James Maxwell. Discover how the development of field theory and the laying of the first transatlantic telegraph cable influenced our understanding of light propagation. Examine Einstein's revolutionary ideas and their impact on modern physics. Gain insights into the relationship between mathematics and physics, and ponder the nature of electric fields in vacuum. This thought-provoking talk by Prof John C.H. Spence, a Fellow of the Royal Society, offers a comprehensive journey through the history of light speed measurement and its profound implications for our understanding of the universe.
Overview
Syllabus
Intro
What medium supports the propagation of starlight across the emptiness of outer space?
Transit of Venus - measuring the earth-sun distance 1761/9
Hippolyte Fizeau (1819-1896). First accurate measurement
Leon Foucault (1819-1868). The best experimentalist
Faraday and Field Theory
James and Katherine Maxwell in 1869 with dog Toby
Laying the first transatlantic telegraph cable (1857) Kelvin explains Why doesn't Morse code arrive at speed of Light
Does light pick up the speed of the passing Aether, like water waves in a river with a current ?
Albert Einstein (1879-1955)
Light-sensitive protein wriggles when absorbing a photon.
On mathematics and physics: Or what stuff does an electric field in vacuum consist?
Taught by
The Royal Institution
