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Thread: does gravitational time dilation slow light down?

  1. #1
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    does gravitational time dilation slow light down?

    I've never been completely sure about this.
    Formerly Frog march..............

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  3. #3
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    Quote Originally Posted by grapes View Post
    I read about the red shift experiment in a tower a while ago.

    I know that the speed of light stays the same locally, but does light speed stay the same in a gravity well, for an observer who is further away from the gravity well?
    Formerly Frog march..............

  4. #4
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    Quote Originally Posted by WaxRubiks View Post
    I read about the red shift experiment in a tower a while ago.

    I know that the speed of light stays the same locally, but does light speed stay the same in a gravity well, for an observer who is further away from the gravity well?
    Local is all that matters in GR. If you extend your own coordinates to somewhere far away, you'll find that the speed of light in your coordinates isn't equal to c. The most extreme example being the slow Schwarzschild-coordinate velocity of photons escaping from just above the event horizon. Which, we now, is not what's experienced locally.

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