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Could absolute motion exist in higher dimensions, if they exist?

  1. Apr 24, 2013 #1
    If the universe follows a 3-torus or finite unbounded shape, or we are situated
    on the surface of a 4D sphere, then the 'centre' if the universe will exist. If one could
    locate the position of this origin in 4D space, and remain stationary with respect to it, then would that object be at absolute rest?

    I was recently thinking about the concept of absolute rest, and why it cannot be defined. I understand that this is because everything is moving relative to everything else. For instance, if space is expanding, I’ve heard that everything is ‘moving’ away from everything else, and NOT from a point of origin. So it seems that a ‘centre’ of the universe cannot be located. Otherwise, we could say that if you remained stationary to this central point, then you would be at absolute rest.

    However I’ve also heard of theories that the topology of the universe may be some closed shape in 4D, for instance a ‘doughnut’ shape. This is why we might not be able to perceive boundaries or origin points in our 3D perspective. But then I ask, if somehow you were able to probe or “peer” into the fourth dimension, or even map it out in some palpable way, and locate the origin point of the Big Bang in 4D (not 3D), and could somehow remain stationary relative to this point (in 4D)- would this then technically be absolute rest? (Assuming of course that there are no other universes but ours).

    Or would a 4 dimensional view of the Big Bang resemble something counterintuitive to us such as an explosion coming from all directions at once? I’m assuming a 0-dimensional point is perceived as a unique 0-dimensional point to ALL dimensions?

    So perhaps this boils down to my question of ‘Is the principle of ‘relative’ motion invariant to hypothetical observers in higher dimensions or just us? If the origin point of the Big Bang in spacetime could be ‘pinpointed’ in a higher dimension, could this point be considered absolute and all motion relative to it considered absolute motion?
  2. jcsd
  3. Apr 24, 2013 #2


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    Staff: Mentor

    There are possible spacetime geometries where the global structure gives some reference frames with special properties - like the largest volume or whatever. That does not need any special geometry, you can just take the comic microwave background and calculate all velocities relative to that. Physics is still the same in all reference frames, so it is just a matter of definition if you want to call motion relative to the CMB as "absolute".
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