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Einstein's theory of relativity

  1. Apr 17, 2016 #1
    1. A falling apple made Newton to think about gravity. What made Einstien to think and develop his theory of relativity ?
    2. What devices/apparatus/equipment did he use for his theory of relativity ?
     
  2. jcsd
  3. Apr 17, 2016 #2

    QuantumQuest

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  4. Apr 17, 2016 #3

    mfb

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    I moved the thread.
    The name is Einstein, not Einstien. And the story about Newton is a nice myth...
    The problems with the existing theories, in particular Maxwell's laws of electrodynamics which don't work well together with Newtonian physics and experimental results about the speed of light.
    Einstein did not do experiments, but he knew about experimental results from others. Therefore: pen and paper.
     
  5. Apr 17, 2016 #4

    Ibix

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    ...and, with the way theory development tends to go, probably a large waste paper bin.
     
  6. Apr 17, 2016 #5
    So, what made others to think in this direction ? And what device/equipments they used for this ?
     
  7. Apr 17, 2016 #6

    mfb

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    Which others, which direction?
    Probably the most important experiment that lead to special relativity was the Michelson–Morley experiment.

    You can find all those things in the corresponding Wikipedia articles.
     
  8. Apr 17, 2016 #7
    For the general theory of relativity, read about the Equivalence Principle. It illustrates the type of thought experiments that Einstein used.
     
  9. Apr 17, 2016 #8
    Hy Anjum S Khan, my belated welcome to PF Forum

    What? It's a myth?
    One stone (ein stein) didn't use any devices, mostly he used thought experiments,
    But GPS clock synchronization is the proof of Einstein theory. And you can read something about muon.
    Muon particle, as I read, should decay in about 2 microsecond. Yet from 16 km above the atmosphere, some of them can reach ground.
    <<Mentor note: Link deleted>>
    But, they're just the proof of this theory not the devices to develop this theory.
    Sincerely
     
    Last edited by a moderator: Apr 18, 2016
  10. Apr 17, 2016 #9
    Einstein's primary motivation came from reading Lorentz's 1904 paper, "Electromagnetic Phenomena in a System Moving with any Velocity less than that of Light", which contains the Lorentz transformation and length contraction equations, and asserted the undetectability of "ether": "It will therefore be impossible to detect the influence of the Earth's motion on any optical experiment". He also was motivated by Poincare's 1904 "Sur la dynamique de l'electron", who stressed the subtleties of synchronizing clocks by speed-of-light signals and the idea of "local time" (time seeming to be dilated), and concluded that it was "as though" the ether didn't exist. Einstein's 1905 paper "On the Electrodynamics of Moving Bodies" borrowed their equations, adding the concept of relativity of simultaneity, explicit time dilation, velocity addition formula, and rejection of "ether".

    Lorentz and Poincare were motivated by the experiments of Michelson-Morley and Trouton-Noble; and the work of Fitzgerald, Voigt, Rayleigh and Brace, and many others, who figured out most of the basic concepts between 1882 and 1900, starting from Maxwell's equations. Unlike Einstein, none of these physicists dreamed about riding on a light beam.
     
    Last edited: Apr 18, 2016
  11. Apr 18, 2016 #10

    mfb

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    He probably saw apples falling, but a large fraction of the population does that. It's not like he saw an apple falling and thought "oh, gravitational force is Mm/r2". Wikipedia discusses this in some detail.
    You cannot prove a theory. You can only fail to disprove it, and if you do that thousands of times with increasing precision, you realize that a theory is good.
    The 2 microseconds are an average, but more muons reach the ground than you would expect in classical mechanics.
     
  12. Apr 18, 2016 #11
    1 year for SR. 10 years for GR
     
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