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Mirror questions

  1. Aug 13, 2010 #1
    Q1 if you were travelling at .99c and held a mirror at arms length orientated perpendicular to your direction of travel would you see a perfect reflection?

    Q2 if you were hovering within a few feet of the event horizon of a black hole and, as before, held a mirror at arms length 'horizontally' would you see a perfect reflection?

    Q3 is there any similarity between the effects observed in the Q1 scenario and the Q2 scenario?
  2. jcsd
  3. Aug 13, 2010 #2
    Q1) Essentially yes. Your face would be reflected perfectly, because it is at rest with the mirror. The starry background might look a little weird due to aberration effects that makes it look like most of the background stars are in front of you.

    Q2) Imagine that we replace the black hole with a dense body that is very nearly a black hole, so that we could in principle stand on the body and see its surface. Instead of looking like you are standing on the surface of a sphere, it would look like you are standing at the lowest point of a bowled surface. There will be visual distortions making it clear you are in extreme curved spacetime and there will be some some distortions in the mirror, but these might be small due to the short distances considered (arm's length) .

    Q3) Not much. If you held the mirror so that the reflection light path is essentially vertical in the gravitational field then there would be some similarities with the (small) distortions you would see in a mirror when you are inside a rocket accelerating in flat space.
  4. Aug 13, 2010 #3
    Kev - re. your answer to Q2 what do you think would the be the visual effect if, for arguments sake, the black hole sphere is so large that for all intense and purpose the surface was flat (I'm assuming this would result in flat spacetime)?
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