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Q about the spacetime bending

  1. Feb 6, 2008 #1
    http://en.wikipedia.org/wiki/Image:Spacetime_curvature.png" [Broken]

    The picture linked above shows the spacetime curvature. Apparently, it's a 3d model.

    But it's not! What i think (and basically trying to find out about) is that space itself is imagined as the 2d grid. What the earth does is bends it into the 3rd dimension.

    So, with an actual 3d grid, wouldn't this actually be bending not space [3rd dimension] but time [4th]? instead of bending the 2nd dimension into the 3rd, i think it would bend the 3rd into the 4th.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Feb 7, 2008 #2


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    That's what the picture does. The concept is that Earth bends these two dimensions in itself, not into a third dimension. The third dimension is merely to help your imagination.
    In real life, there are 4 dimensons which are bent not into a fifth dimension, but into themselves.
  4. Feb 7, 2008 #3


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    Exactly, it shows only the curvature of space not spacetime. The difference is explained here:

    Depends how you define the grid dimensions. You can also have a 2d grid, representing 1 space dimension and the time dimension, to show the curvature of spacetime. This is done in the links I provided in https://www.physicsforums.com/showpost.php?p=1557122&postcount=4".
    Last edited by a moderator: Apr 23, 2017
  5. Feb 7, 2008 #4
    thanks for the quick response.

    dude. that is cool.
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