Faster than the speed of light (pulling on a string)?

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Discussion Overview

The discussion revolves around the concept of whether pulling on a string connected between two stars could result in communication that is faster than the speed of light. The scope includes theoretical implications of such a scenario and the physical properties of materials involved.

Discussion Character

  • Debate/contested, Conceptual clarification

Main Points Raised

  • One participant proposes that pulling one side of a string would result in the other side being pulled immediately, suggesting a form of communication faster than light.
  • Another participant counters that the response would not be immediate and would occur at the speed of sound in the string, due to the material properties of the string.
  • A further contribution emphasizes that the string's "stretchiness" means that the extension from pulling would travel down the string at a speed determined by the speed of sound in that material.
  • One participant references a FAQ on the topic, indicating that this question has been addressed previously in the community.

Areas of Agreement / Disagreement

Participants express disagreement regarding the nature of the communication speed, with some asserting it could be instantaneous while others clarify that it would not exceed the speed of sound in the string.

Contextual Notes

The discussion does not resolve the assumptions regarding the properties of the string or the implications of the scenario, leaving open questions about the nature of communication through physical materials.

Who May Find This Useful

This discussion may be of interest to those exploring concepts of communication speeds in physics, the properties of materials, and theoretical scenarios involving relativistic constraints.

Ozs
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If you were to connect a string from one star to another (assuming everything remains still), and then you were to pull one side of the string towards you, the other would be pulled immediately, thus the "communication" between the two edges is technically faster than the speed of light? Does this make sense?
 
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Ozs said:
If you were to connect a string from one star to another (assuming everything remains still), and then you were to pull one side of the string towards you, the other would be pulled immediately, thus the "communication" between the two edges is technically faster than the speed of light? Does this make sense?
No, not immediately and not even at speed of light. It occurs at the speed of sound. You will find probably dozens of threads on PF here, which deal with this idea.
 
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The other end wouldn't get pulled immediately, because the string has a certain amount of "stretchiness" to it. So, when you pull your end, the string will stretch a bit and that extension will travel down the string at approximately the speed of sound in the string.
 
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Ozs said:
If you were to connect a string from one star to another (assuming everything remains still), and then you were to pull one side of the string towards you, the other would be pulled immediately, thus the "communication" between the two edges is technically faster than the speed of light? Does this make sense?

This type of question has been asked so many times, there is a FAQ on it:

https://www.physicsforums.com/insights/can-i-send-a-signal-faster-than-light-by-pushing-a-rigid-rod/

Zz.
 
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The link to the FAQ should take care of the OP's question. Thread is closed.
 

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