Time dilation is not about clocks or light, it’s about time itself.


Measures of time are simply different for different observers in motion relative to each other.


Time dilation is often described by saying “moving clocks run slow”. Can you see the problem with this statement? It infers that there’s one clock that’s right, and the rest are all slow, which totally violates the principle of relativity!


For relativity to hold true, the observer in a fast plane would feel nothing usual is happening whatsoever! The observer in the plane doesn’t experience slow motion or anything else strange like that. In fact, the watch on her wrist still ticks by as it always has. She does not notice anything unusual in her reference frame.


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Comments

11 Responses to “Time Dilation and Length Contraction”

  1. All of us are moving forward in time. The issue is that time passes at different rates based on the particular point of view. But you can never become younger.

  2. youngsurrender says:

    You’ll never be the same age again?! What if you went forward in time? Would it be too complicated to be the same age again, or does it not matter when you leave? -Sasha

  3. gtearnest says:

    wow 😉

  4. vanessa LUDIK says:

    so if you look at the twins, the “correct” time will be the time for the twin on the spacecraft that travels the speed of light. because the time on earth will be too fast. you can only move forward in time, so if we look at the twins again, the twin on earth time traveled but the twin on the spacecraft did not?

  5. Mary Cartwright says:

    Wait wait wait… If Bill and Jim have clocks, and Bill goes on a spaceship to orbit the earth at the speed of light, and he lands and they compare their clocks, is Bill’s clock faster or slower? Also, if Jim boards the spaceship, is his clock slower?
    You also said that they perceive each other’s clocks to be slower, but then how does Jim see Bill’s clock as slow, even when Bill lands his will be ahead of Jims’s?
    MIND = BLOWN.

  6. No, sadly you can’t have a negative speed, and time only progresses in one direction.

  7. Lori Jorgensen says:

    If you had negative c could you go back in time.

  8. Sadly, no. Time only moves in one direction. did you see the thought experiment about “elsewhere” time?

  9. Linda Conrad says:

    Is reverse Light speed possible to travel back in time??

  10. Kaelen Davis says:

    It’s very complicated, yes.

  11. Marta Brantley says:

    My head hurts 🙂