Solving the Paradox of Rope: Transmission of Info in GR

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Discussion Overview

The discussion revolves around a thought experiment involving a rope tied between the Earth and the Sun, focusing on the transmission of information when the rope is cut. Participants explore the implications of General Relativity (GR) on the speed of information transfer, considering factors such as wave speed in the rope and the nature of signals in a relativistic context.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant poses a question about the speed at which a dynamometer would register the cutting of the rope, suggesting that it cannot be instantaneous due to GR.
  • Another participant mentions the wave speed in the rope as a factor that could provide insights into the problem.
  • A different participant affirms the relevance of the speed of sound wave in the rope, indicating that this is how information would transmit under the given conditions.
  • One participant references a related FAQ that discusses the possibility of sending signals faster than light, implying that the resolution of this paradox may be similar.

Areas of Agreement / Disagreement

Participants express varying views on the speed of information transmission, with some focusing on the wave speed in the rope and others referencing the implications of GR. The discussion does not reach a consensus on the exact nature of the information transmission speed.

Contextual Notes

The discussion does not resolve the assumptions regarding ideal conditions and the specific properties of the rope, nor does it clarify the mathematical implications of the proposed scenario.

Javier Chornet
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I was thinking about a gendanken experiment that I don't know how to solve:

Imagine we tie one extrem of a rope in the Earth and the other one in the Sun, with some tension, and connected to a dynamometer (obviously in ideal conditions: no heat, no rotation etc.).
My question is: when will the dynamometer feel that we've cutted the rope in the earth?
In other words: what's the speed of transmision of the information? Inmediatly? (Obviously not because GR) At the speed of light? At the speed of the waves in the rope?

What's your opinion? Can anybody demonstrate what will happens?
 
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The wave speed in the rope.

This might give you some insights:
 
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Likes   Reactions: Ibix, Javier Chornet, vanhees71 and 1 other person
Very cool! Had seen this quite a while ago but had forgotten, so thanks for reminding.:cool:
 
Very interesting experiment!
In speed of sound wave in rope with the given tension the information transmits.
 
Last edited:

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