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

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
4 replies · 2K views
Ozs
Messages
1
Reaction score
0
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?
 
Physics news on Phys.org
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.
 
  • Like
Likes   Reactions: CWatters
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.
 
  • Like
Likes   Reactions: hsdrop and CWatters
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.
 
  • Like
Likes   Reactions: CWatters, davenn and Dale
The link to the FAQ should take care of the OP's question. Thread is closed.