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Original motivations for GR?

  1. Apr 23, 2007 #1

    quasar987

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    Original motivations for GR??

    I'm sitting here and wondering what was Einstein trying to do when he "discovered" GR?

    For instance, the biggest motivation for SR was the apparent constancy of the speed of light. That's the problem he was trying to fix.

    What was it for GR? Was it just the tiny precession thingy of Mercury? Was looking for a new theory of gravitation, or something else?

    How did it all unfold?
     
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  3. Apr 23, 2007 #2

    Chris Hillman

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    Assuming your interest is historical, not physical, it would be misleading to try to summarize Einstein's motivations, which were complex, without even discussing the historical context!

    Try these books:

    http://math.ucr.edu/home/baez/RelWWW/HTML/reading.html#hist
     
    Last edited: Apr 23, 2007
  4. Apr 23, 2007 #3

    quasar987

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    I would accept a misleading summary. o:)

    (Btw, what is in your eye the distinction btw the historical and the physical interest one can have in this question?)
     
  5. Apr 23, 2007 #4

    Chris Hillman

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    Then Wikipedia is just what you want.

    Why do you ask? I mean, how curious are you? I don't think any of this is easy to explain in a few words. At the same time, it is not clear to me that it is worth taking the time to discuss these issues properly.
     
    Last edited: Apr 23, 2007
  6. Apr 23, 2007 #5

    quasar987

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    Ok well thanks anyway.
     
  7. Apr 23, 2007 #6
    I always thought it was to find a relativistically correct theory of gravitation. But I might be very wrong...
     
  8. Apr 23, 2007 #7
    In 1907 Johannes Stark asked Einstein to write a monograph on SR for the jorunal Jahr-buch der Radioaktivitat. During the time he was writring this article Einstein came to see that all the laws of physics except for gravity could be dealt with in sr. So he started to search for a reason why this was so. Einstein's break through in this problem came as he was sitting in his patent office thinking about this problem it suddenly occurred to him that if a person were to jump off of a roof then while he was in free-fall he would not detect the force of gravity anywhere near him. It was like he was in an inertial frame. I guess is it was shortly after that that he reversed the problem and figured out that a person who changes from an inertial frame of reference to a uniformly accelerating one would observer a uniform gravitational field "produced" in this new set of accelerating coordinate system. The work wento on fropm there.

    You can find more details on Einstein's thoughts in the Physics Today article in the August 1982 Edition. This is a translation of an address he was to give in 1922 in Japan
    (when he was supposed to be in Stockholm getting his Nobel Prize). I permanently placed this article on my website. Go to

    www.geocities.com/physics_world

    Then scroll down to you see "How I created the theory of relativity." I tried to direct link it but it didn't work. GR has a long and complicated history and cannot be placed in a post. To get more than this brief look you'd have to by a book such as that by Pais on Einstein's life and work.

    Enjoy!

    Pete
     
    Last edited: Apr 23, 2007
  9. Aug 9, 2008 #8
    Re: Original motivations for GR??

    The motivation for GR is not just the speed of light. In the 1905 paper Einstein considered the frames of reference which were moving with a uniform velocity viz. unaccelerated systems and revolutionized physics by dismissing the absolute nature of space and time.The GR is a logical extension for the generalizing for uniformly accelerating reference frames starting with the principle of equivalence and preserving the fundamental laws of physics.
     
  10. Aug 10, 2008 #9
    Re: Original motivations for GR??

    Try Einstein's own writings, including his original GR paper. He makes it pretty clear what his motivations were. Primarily, he was dissatisfied with the preferential treatment given to inertial reference frames in SR.

    Here is a link to his 1916 GR intro (English translation): http://hem.bredband.net/b153434/Works/Einstein.htm

    Al
     
  11. Aug 10, 2008 #10

    A.T.

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    Re: Original motivations for GR??

    The same thing actually. Since light rays are bend by gravitation, the "inner part" of the beam travels a shorter distance then the "outer part" in the same time. The only way for both parts to have the same local velocity, is to assume different local time rates in a gravitational field. But this distortion of the time dimension gives you only half of the bending effect. The rest and the orbit precessions are explained by the spatial distortion.
     
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