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B What was the epiphany of the light speed limit?

  1. Jun 14, 2017 #1
    How did Einstein first contemplate the idea that the speed of light was constant in all frames or reference?
    Did he say "I wonder what would happen if we considered light speed to be constant" in some kind of thought experiment. Did the concept fall serendipitously from the results of calculations?

    I'm just wondering how it would occur to someone to think of that when additive velocities were just generally assumed. The very idea of a constant light speed was so bizarre in that realm of thought that I'm curious, especially when time being a linear constant was so accepted. I'm sure the story is out there but I can't find it.

  2. jcsd
  3. Jun 14, 2017 #2


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    Staff: Mentor

    The idea that the speed of light was constant actually predates Einstein I believe. If I remember correctly, it dates back to the mid-1800's when classical electrodynamics was developed fully and certain problems were noticed. See here: https://en.wikipedia.org/wiki/History_of_special_relativity
  4. Jun 14, 2017 #3
    It was an observation. Experiments showed the speed of light is invariant.

    Relativity was an explanation

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  5. Jun 17, 2017 #4

    Mister T

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    I think he claimed it came from his study of electromagnetism. If a loop of wire is moved relative to a stationary magnet a current arises in the wire. And if a magnet is moved relative to a stationary loop of wire a current arises in the wire. Einstein was able to show that these two interactions are the same, a symmetry that was lacking in the laws of electrodynamics.
  6. Jun 17, 2017 #5

    This is what I gathered from reading On the Electrodynamics of Moving Bodies.

    Edit- might as well post it to save someone a google search.

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