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Light entering a Black Hole and Hawking radiation

  1. Oct 16, 2013 #1
    Hi all, I was wondering if, when a beam of light is pulled towards a black hole , because it can't accelerate, it is blueshifted? Thanks in advance.
  2. jcsd
  3. Oct 16, 2013 #2


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    Hi Superposed_Cat! :smile:

    If two people with identical flashlights are stationary at the top and bottom of a mountain, shining the flashlights at each other,

    the top person will see the light redshifted, and the bottom person will see the light blueshifted.

    It's the same for stationary observers near a black hole …

    the gravitational effect of a black hole is (outside the event horizon and outside the surface of the star) exactly the same as that of a star of the same mass.
  4. Oct 16, 2013 #3
    Thanks tiny-tim :). Good day fine sir.
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