Time Dilation and Length Contraction near the Event Horizon of a BH

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SUMMARY

The discussion centers on the effects of time dilation and length contraction experienced by observers near the event horizon of a black hole (BH). It is established that a free-falling observer does not experience length contraction or time dilation; these phenomena are only measurable from the perspective of distant observers. The conversation also explores how gravitational fields may cause visual distortions, such as the apparent flattening of objects in the direction of gravitational attraction, similar to effects observed at relativistic speeds. The complexities of measuring these effects and the implications for visual perception of the universe are also examined.

PREREQUISITES
  • Understanding of general relativity and its implications for black holes.
  • Familiarity with the concepts of time dilation and length contraction.
  • Knowledge of Schwarzschild solutions in gravitational physics.
  • Basic grasp of observational techniques in astrophysics.
NEXT STEPS
  • Research the effects of gravitational time dilation near black holes.
  • Study the Schwarzschild metric and its implications for spacetime geometry.
  • Explore the concept of Einstein rings and their formation in gravitational lensing.
  • Investigate experimental proposals for measuring length contraction in gravitational fields.
USEFUL FOR

Astronomers, physicists, and students of general relativity who are interested in the effects of gravity on time and space, as well as those studying black hole physics and observational astrophysics.

  • #31
zonde said:
What is mainstream terminology if one is describing such transformation?
I don't think there is any. That is the problem. Gravitational time dilation is well defined for static spacetimes, but not gravitational length contraction. Both you and PAllen have suggested reasonable definitions, but since neither is standard it would be good for the OP to weigh in and describe what they are referring to in their question.

zonde said:
Hmm, where did you get this?
Sorry about misunderstanding. I was (overly) focusing on 1 simply because that was the one you mentioned in association with length contraction.
 
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  • #32
DaleSpam said:
I don't think there is any. That is the problem. Gravitational time dilation is well defined for static spacetimes, but not gravitational length contraction.
When two observers are next to each other we can speak about pure SR effects in order to compare what they see. SR holds locally and there is no need to speak about any GR effects.
 
  • #33
zonde said:
When two observers are next to each other we can speak about pure SR effects in order to compare what they see. SR holds locally and there is no need to speak about any GR effects.
Right, but the OP is interested in GR effects.
 
  • #34
DaleSpam said:
Right, but the OP is interested in GR effects.
Well, right. But posts #6 and #8 seemed to say that it might be good to start with differences between what is seen by hovering observer and what is seen by falling observer.

At least we can assume that one of them is more "natural" observer and then we can find out what the other one is seeing. And yes, I was explaining it from perspective that more "natural" observer is hovering observer as we generally are that type of observers.
 

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