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Q & A: unstretchable strings?

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Most recent answer: 02/10/2015
Q:
I realize in theory nothing can travel faster than the speed of light. However, I was wondering if there is a principle that considers the possibility of instantaneous travel of some type of energy by using a theoretical string that extends between two points. To illustrate, if there was a piece of string that could not stretch, compress, or decompress, and that string extended for one light year between two points, then by pulling or pushing that string on one end the opposite end that is a full light year away should instantaneously move to match the pull or push. Is there a theory in physics which explores this concept? If so, wouldn't this theory allow for faster than light travel, at least of some form of energy?
- Craig (age 31)
Little rock, AR
A:

You're reasoning about the implications of rigid rods and unstretchable strings is correct. Either the whole structure of relativity breaks down or those things can't exist. It turns out those things can't exist. See this old thread:

In a way it's unfortunate that something as familiar as light happens to travel at the universal speed limit. That lets people think that the speed limit is some special feature of light. It isn't. 

Mike W.


(published on 02/10/2015)

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