This book tells the human story of one of mankind’s greatest intellectual adventures - how we understood that light travels at a finite speed, so that when we look up at the stars we are looking back in time. And how the search for an absolute frame of reference in the universe led inexorably to Einstein’s famous equation E = mc2 for the energy released by nuclear weapons, which also powers our sun and the stars. From the ancient Greeks measuring the distance to the sun, to today’s satellite navigation and Einstein’s theories, the book takes the reader on a gripping historical journey. How Galileo with his telescope discovered the moons of Jupiter and used their eclipses as a global clock, allowing travellers to find their Longitude. How Roemer, noticing that the eclipses were sometimes late, used this delay to obtain the first measurement of the speed of light, which takes eight minutes to get to us from the Sun. From the international collaborations to observe the Transits of Venus, including Cook’s voyage to Australia, to the extraordinary achievements of Young and Fresnel, whose discoveries eventually taught us that light travels as a wave but arrives as a particle, and the quantum weirdness which follows. In the nineteenth century we find Faraday and Maxwell, struggling to understand how light can propagate through the vacuum of space unless it is filled with a ghostly vortex Aether foam. We follow the brilliantly gifted experimentalists Hertz, discoverer of radio, Michelson with his search for the Aether wind, and Foucault and Fizeau with their spinning mirrors and lightbeams across the rooftops of Paris, competing to be the first to measure the speed of light on earth. The difficulty of sending messages faster than light using quantum entanglement, and the reality of the quantum world conclude this saga.
The Absolute Frame of Reference