Nothing is faster than Light, Right?

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SUMMARY

The discussion centers on the misconception that a rigid rod can transmit a signal faster than the speed of light (c) by pushing it. The example presented involves a 1-meter push on a 1 light-year long steel rod, suggesting that the entire rod would move instantaneously. However, the consensus is that the signal propagates at the speed of sound in the material, not instantaneously or faster than light. This highlights the importance of understanding the limitations imposed by the laws of physics, specifically in the context of special relativity.

PREREQUISITES
  • Understanding of special relativity principles
  • Knowledge of signal propagation speeds in materials
  • Familiarity with the concept of rigid bodies in physics
  • Basic grasp of the speed of light as a universal constant
NEXT STEPS
  • Research the speed of sound in various materials, particularly steel
  • Study the implications of special relativity on signal transmission
  • Explore the concept of rigid bodies and their limitations in physics
  • Read about neutrinos and their speed in the context of modern physics
USEFUL FOR

Physics students, educators, and anyone interested in the principles of relativity and the nature of signal transmission in materials.

Algren
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First of all, let's consider that this question is asked before neutrino's speed was discovered.

" Let's consider a rod, a rod which is as long as 1 light year.

Consider that it is a rigid rod of steel with diameter 1m (to prevent bending)

I gave a nudge to it from one side, then the whole rod will displace, right?

For example, i pushed the rod by 1m, then the rod will move 1m, right?

Ohh, look what happened! Something went faster than light! A lot faster! "

If you didnt get the above case, ill explain what happened:

I used the rod to send a 'message' by pushing and pulling it. Hence, it traveled faster the speed of light, since it conveyed the message through 1 light year almost instantly.

If you disagree with the above, give approximations of the speed of the message, if its not faster than 'c'.
 
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Please read the FAQ in the Special & General Relativity forum about this question. The signal propagates at the speed of sound in the rod.

https://www.physicsforums.com/showthread.php?t=536289

.
 
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