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What is a block universe?

  1. May 23, 2015 #1
    I'm 13, so I was reading Discover and I read something about a "block universe" and I thought it was a bunch of hogwash... here is how I see it... Time is the same for everybody its just how people perceive it that makes people think its an illusion... any feedback? Thanks!
    Last edited by a moderator: May 23, 2015
  2. jcsd
  3. May 23, 2015 #2
    Time is most certainly NOT the same for everyone. It's relative to the observer - it's all derived from Einstein's theory of special relativity.
    It's basically based on the fact that the speed of light is the same for everyone in a vacuum, and since speed is dependent on distance and time, distance and time must be different for different observers to ensure light moves with the same speed relative to everyone.
  4. May 23, 2015 #3


    Staff: Mentor

    The "block universe" is an interpretation of special relativity; it is not the same as SR itself. The "block universe" can be false without making SR itself (including the relativity of time) false.
  5. May 23, 2015 #4
    The block universe just refers to 4 dimensional spacetime. If you try to draw it you will notice your piece of paper has too few dimensions. So, drop one spatial dimension and draw a 2D plane for space. Draw time as the 3rd dimension using perspective and there you have it, the universe represented as a block.

    This is the same reason light cones are called cones when they are really hyperspheres.
  6. May 23, 2015 #5
    Dear spacejunkie,
    thank u for the feedback... it helps a lot
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