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The Lightyear-long Pole

  1. Oct 1, 2013 #1
    Here is a question I posed to my Facebook friends this morning while waiting on my ride to work. I thought about the answer to it myself and got a good brain workout from it!

    I would like to know your thoughts:

    You have a rigid pole that cannot bend or stretch or otherwise deform in any way.
    The pole is exactly one light year in length.
    You pull on one end of the pole and it moves one meter.
    Does the other end move the same distance at the same time? Why or why not?
     
  2. jcsd
  3. Oct 1, 2013 #2

    phinds

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    There is no such pole nor will there ever be. Matter does not work like that. Your disturbance at one end of the pole will travel through the pole at the speed of sound in the pole.
     
  4. Oct 1, 2013 #3

    Nugatory

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    There's an entry in the FAQ at the top of this page: https://www.physicsforums.com/showthread.php?t=536289 [Broken]
     
    Last edited by a moderator: May 6, 2017
  5. Oct 1, 2013 #4
    The existance of the pole is not in question. The properties of such a pole if it were to exist is the question. It is also a subliminal attempt to cause you to think... But if this is too much for you, try an easier problem.

    Thanks.
     
  6. Oct 1, 2013 #5

    phinds

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    If unicorns existed, would their horns be more than a foot long?
     
  7. Oct 1, 2013 #6

    Drakkith

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    I'm sorry, we talk about real physics here, not "what if" questions that break the known laws of the universe.
     
  8. Oct 1, 2013 #7

    phinds

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    Why is that something to be sorry about? I rather like it that way. :smile:
     
  9. Oct 1, 2013 #8

    Drakkith

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    Oh, you... :rolleyes:
     
  10. Oct 1, 2013 #9

    Dale

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    We obviously cannot use the laws of physics to determine the properties of an object that the laws of physics forbids in the first place (ex falso quodlibet). Therefore, anything other than a discussion of why the laws of physics forbid it is speculative.

    Since the OP is clearly not interested in such a discussion, this thread is closed.
     
    Last edited: Oct 1, 2013
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