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Could time be movement in a 4th physical dimension?

  1. Jan 29, 2008 #1
    Let's say the universe exists as a collection of related static 3-d spaces, like in Julian Barbour's book The End of Time. Nothing ever actually moves. The illusion of movement comes from moving from one of these spaces to another which is closely related to the previous one. It's similar to the way flipping through frames of a film generates the appearance of movement.

    OK, now in Barbour's picture you (or your consciousness, or focus of attention) somehow would have to move from one frame to another (unless you never move and just think you do, but that's another story). Also, these frames must physically exist, and be physically seperated from each other.

    Barbour doesn't seem to address this to my recollection, but what if they physically existed as 3-d spaces embedded in a larger 4-d space? Then, moving from one of the 3-d spaces to the next would require movement along the 4th physical dimension, and also would generate the illusion of time. That way, time is literally "moving into the 4th dimension" to the next frame. Only it doesn't feel like you're moving because the place you move to is almost exactly the same as where you were (i.e you're still sitting at your desk even though you're really moving), and you feel no acceleration because you are moving at a constant velocity.

    I am just wondering if this conclusion follows from Barbour's assumptions, or if it has any application elsewhere.

    Any thoughts? Could the velocity of this movement be changed? What if you are also rotating? What would that do?
    Last edited: Jan 29, 2008
  2. jcsd
  3. Jan 29, 2008 #2
    I can't say I'm an expert on physics, but from what I've read, the model presented in your first paragraph cannot possibly describe the 'true' nature of the universe because it does not suit quantum mechanics. On the quantum scale, particles cannot be considered to be 'static'. They do not have a place where they exist. We only know that if we try to find them, they might exist in certain places, but they might not. And if we don't try to find them, the particle behaves like it exists in more than one place.

    The perception of time as a 4th dimension is rather standard in physics, since Albert Einstein's model of space-time. The 'speed' in which you move through time can be altered locally. This is known as 'time dilation'. Time dilation can be caused by movement in any of the 3 dimensions of space (any movement at all, but the effects are most noticeable at velocities approaching C) or by gravity.
  4. Jan 29, 2008 #3
    Barbour addresses this issue in his book. I can't recall the details but he seemed to have a good explanation of how it can still work.

    Time as the 4th dimension is a standard idea, yes. But usually it's not conceived of as being a spatial dimension just like the other 3. I am supposing that it's an actual spatial dimension - qualitatively the same as the others.
    Last edited: Jan 29, 2008
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