1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Nothing is faster than Light, Right?

  1. Jan 13, 2012 #1
    First of all, lets consider that this question is asked before neutrino's speed was discovered.

    " Lets 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'.
  2. jcsd
  3. Jan 13, 2012 #2


    User Avatar

    Staff: Mentor

    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 [Broken]

    Last edited by a moderator: May 5, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook