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Why can't u go faster than the speed of light when speed doesn't exist

  1. Mar 31, 2013 #1
    If you are the only object in the universe, what speed are you going?

    Well there would be no such thing as speed because your speed is only relative to other objects. So if there is no such thing as speed, how is there a speed limit?

    Let me give an example.

    If you take off from earth in a really fast rocket to visit another planet, when you come back, you will have aged less than everyone on earth because time slowed down for you.

    But how did you go faster than the people of earth when its all relative?
    You simple got father away from the people of earth, then you got closer to the people of earth. Who is to say if your rocket moved or the earth moved. There is no difference.
  2. jcsd
  3. Mar 31, 2013 #2


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    Gold Member

    Let's go back to your original idea of you being the only object in the universe and you fire your rocket. Your rockect will leave an exhaust and now you are no longer the only object in the universe. You can consider your motion relative to the exhaust, can't you?
  4. Mar 31, 2013 #3
    If you are all alone, there may not be anything to define inertial vs non-inertial and so c. Interesting here that we can't really use relativity to make sense out of such a hypothetical place.

    - http://en.wikipedia.org/wiki/Mass_in_general_relativity
  5. Mar 31, 2013 #4
    The difference is that the rocket accelerated and then decelerated upon return....THAT distinguishes between the two motions....accelerated motion is different from inertial [non accelerated] motion.

    Sure there is, you'll FEEL non inertial motion just as you do when you accelerate in a car.
  6. Mar 31, 2013 #5
    Something *like* Mach's principle may be responsible for inertia... in the empty pocket universe there might not be anything to supply something like that...

    oh. I guess the rest of the OP is unrelated to the first question. never mind.

    if there's just the Earth, and a rocket, and nothing else in the universe, and that is somehow possible, then it's not clear if / how the aging / acceleration business would work.
  7. Mar 31, 2013 #6


    Staff: Mentor

    When you gain access to such a universe and make said measurements and publish those measurements in a reputable journal then we can discuss them here. Until then it is pure speculation.

    You are welcome to re-post the non-speculative portions of your post in a new thread.
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