Equivalence Principle and Rindler Horizons

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SUMMARY

The discussion centers on the relationship between acceleration, Rindler horizons, and the Equivalence Principle in the context of General Relativity. Participants clarify that standing on Earth does not generate a Rindler horizon directed towards one's feet, as Rindler horizons are phenomena of flat spacetime, while gravitational fields create event horizons. The conversation emphasizes the importance of understanding the local versus global implications of acceleration and gravity, and the necessity of mathematics in grasping these concepts accurately.

PREREQUISITES
  • Understanding of the Equivalence Principle in General Relativity
  • Familiarity with Rindler coordinates and horizons
  • Basic knowledge of spacetime curvature and gravitational fields
  • Mathematical concepts related to acceleration and force, specifically Newton's law of gravitation
NEXT STEPS
  • Research the implications of Rindler horizons in flat spacetime
  • Study the differences between event horizons and Rindler horizons
  • Explore the mathematical foundations of the Equivalence Principle
  • Learn about the effects of spacetime curvature on gravitational fields
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Students and enthusiasts of physics, particularly those interested in General Relativity, spacetime concepts, and the mathematical foundations of these theories.

  • #31
vanhees71 said:
It is, at least as far as I can imagine, impossible to discuss the topic of this thread, i.e., Rindler coordinates and Rindler horizons to locally describe the region close to an event horizon in GR, without using the adequate math.
The question was if a Rindler Horizon forms when you stand on a massive body. The answers can be yes, no, or nobody knows, and none of those answers require math, nor was math desired.
 
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  • #32
vanhees71 said:
This is the 30th posting within this thread, and we've not achieved anything to answer the question yet.
I disagree. The question has been answered, and at a B level, without math.
 
  • #34
sbaker8688 said:
The answers can be yes, no, or nobody knows, and none of those answers require math, nor was math desired.
That's disingenuous.

You got an answer like this, immediately challenged it by demanding a source, and then complained that the source used "technobabble".
 
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  • #35
The weak-field approximation for time dilation is Td = 1 + 𝜙/c². The Rindler horizon occurs when 𝜙 = -c²; in a 1 G field, that is about 1 light year "below" you. At that point, the formula gives Td = 0, i.e. time stops running.

In SR, the Rindler horizon actually exists, because the linear equation is exact. But for gravity, it's only the first order approximation. The actual equation is Td = exp(𝜙/c²). [Einstein 1907] Time never stops unless 𝜙 goes to minus infinity. So there is no Rindler horizon. (There may still be black hole event horizons, etc.)

The Einstein equivalence principle says that gravity and acceleration are locally indistinguishable. Here "locally" means "over short enough distances that the linear approximation is good and you can't see higher order terms". It doesn't say that they are globally indistinguishable. They're not.
 
  • #36
sbaker8688 said:
The question was if a Rindler Horizon forms when you stand on a massive body.
As @Dale has already pointed out, this question has been answered. The answer is no.

Thread closed.
 
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