Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Once upon a time.

  1. Jun 12, 2010 #1
    The top speed of information is c.

    1. Then is it correct to say that theoretically there cannot be any simultaneous happenings in the universe (like theories depend on causality)?

    2. Is it then correct to deduce that only one particle in the universe is at changing state at a given time (Planck time?)?

    3. So - theoretically - no single particle can even move and rotate simultaneously... ?

    4. Or can not move "along more than one axis" at a time (Planck time?)... ?

    5. Again I'm confused... :D ?
  2. jcsd
  3. Jun 12, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Your first assumption is incorrect.
    There's no objection to simultaneous events, it's just that "simultaneous" has different meanings to different obervers.
    "Simultaneous" just means: light signals from these events reach my clock at the same instant of time.
    Note that simultaneity is something different from causality. "Even" in relativity, if event A happened before B in some arbitrary frame, then there will be no equivalent frame in which B takes place after A).
  4. Jun 12, 2010 #3
    ... and they all lived happily ever after, or, originally, "happily until their deaths".

    Sorry - embarrassed - once again...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook