If a person could, theoretically, catch up to a beam of light and see it frozen relative to their own motion, would physics as a whole have to change depending on a person's speed, and their vantage point? Instead, Einstein recounted, he sought a unified theory that would make the rules of physics the same for everyone, everywhere, all the time. But because it appeared in Einstein's own memoir, the anecdote is still widely accepted. Norton challenged Einstein's story in his book ' Einstein for Everyone' (Nullarbor Press, 2007), in part because as a 16-year-old, Einstein wouldn't yet have encountered Maxwell's equations. But, Einstein wrote, this contradicted work by another scientist, James Clerk Maxwell, whose equations required that electromagnetic waves always move at the same speed in a vacuum: 186,282 miles per second (300,000 kilometers per second). In a thought experiment as a teenager, he wrote, he imagined chasing a beam of light.Ĭlassical physics would imply that as the imaginary Einstein sped up to catch the light, the light wave would eventually come to a relative speed of zero - the man and the light would be moving at speed together, and he could see light as a frozen electromagnetic field. How did Einstein come up with special relativity?Īccording to Einstein, in his 1949 book ' Autobiographical Notes' (Open Court, 1999, Centennial Edition), the budding physicist began questioning the behavior of light when he was just 16 years old. That meant it couldn't be explained by classical mechanics. If the speed of light didn't change despite the Earth's movement through the ether, they concluded, there must be no such thing as ether to begin with: Light in space moved through a vacuum. Michelson and chemist Edward Morley calculated how Earth's motion through the ether affected how the speed of light is measured, and unexpectedly found that the speed of light is the same no matter what Earth's motion is. In 1887, wrote astrophysicist Ethan Siegal in the Forbes science blog, Starts With a Bang, physicist Albert A.

Researchers set about trying to detect that mysterious ether, hoping to understand it better. To shoehorn the odd behavior of light into Newton's framework for physics scientists in the 1800s supposed that light must be transmitted through some medium, which they called the 'luminiferous ether.' That hypothetical ether had to be rigid enough to transfer light waves like a guitar string vibrates with sound, but also completely undetectable in the movements of planets and stars. But some things couldn't be explained by Newton's work: For example, light.

Albert einstein theory of relativity