Could FTL Communication be Achieved via Mechanical Connection?

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Discussion Overview

The discussion revolves around the possibility of faster-than-light (FTL) communication through a mechanical connection, specifically using a hypothetical rigid rod between two bodies in space. Participants explore the implications of such a scenario on the transmission of pressure versus the speed of light in communication.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant presents a scenario involving two bodies in space, questioning whether pressure transmitted through a rigid rod would reach one participant before a radio message does.
  • Another participant argues that if the rod is made of any known material, the pressure will arrive at the same time or later than the radio message, asserting that FTL communication is not possible in this context.
  • A further contribution explains that the speed of transmission in solids is limited by electromagnetic interactions, emphasizing that for all known materials, this speed is significantly less than the speed of light.
  • One participant references an external article for additional insights on the topic, suggesting that this question has been addressed previously in the forum.
  • Another participant reiterates that if the rod is made of material consistent with chemical physics, the speed of pressure transmission will always be less than the speed of light.

Areas of Agreement / Disagreement

Participants generally agree that, based on current understanding of physics, FTL communication via a mechanical connection is not feasible. However, there is no consensus on the implications of hypothetical materials or scenarios that could alter this understanding.

Contextual Notes

The discussion is limited by assumptions regarding the properties of materials and the nature of pressure transmission. The implications of hypothetical materials that do not conform to known physical laws are not fully explored.

Glenstr
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Say we have this scenario, we have two bodies (big rocks, asteroid etc), existing in the vacuum of space, both are in perfect sync with each other (distance between them remains static) and are 1 light second apart in distance. Bob is standing on one rock and Mary on the other. Each has a radio, but there is also a long rod made of some material we haven't discovered yet that does not bend, stretch or compress when stress is put on it. Both Bob and Mary are hanging on to one end of the rod. Bob says "hi Mary" at the exact same time he pushes on the rod.

Will Mary feel the pressure on the rod at her end before she hears Bob say "hi"?
 
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Glenstr said:
Say we have this scenario, we have two bodies (big rocks, asteroid etc), existing in the vacuum of space, both are in perfect sync with each other (distance between them remains static) and are 1 light second apart in distance. Bob is standing on one rock and Mary on the other. Each has a radio, but there is also a long rod made of some material we haven't discovered yet that does not bend, stretch or compress when stress is put on it. Both Bob and Mary are hanging on to one end of the rod. Bob says "hi Mary" at the exact same time he pushes on the rod.

Will Mary feel the pressure on the rod at her end before she hears Bob say "hi"?
If the material is made of any currently known form of matter or energy, and held together by any currently known interaction, then the push will arrive at the time the radio message arrives, or later.
In other words, the answer to the title is No.
 
To expand just slightly on Slowthinker, the speed of transmission in a solid is the speed of sound in that solid and is limited by electromagnetic interactions (atom's electrons banging into each other) and for all substances make of atoms, is approximately zero compared to the speed of light.

This question is answered here frequently. Lots of people have this mistaken idea.
 
If the rod is made of material that satisfies chemical physics, pressure goes as sound wave the speed of which is less than light speed. I am sorry for this boring answer.
 
Thanks - all I needed to know! :-)
 

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