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Gravity, my thoughts

  1. Mar 17, 2009 #1
    If we live in a 4 dimensional universe, doesn't it only make sense that object which exist in it, exist in all 4 dimensions?

    I think, a majority of people think of time as a separate dimension from the 3 of space.

    That is to say, a ball, floating in space affects all 4 dimensions, 3 of space and the one of time. Too often we only think of the 3 - we paint a static picture.

    Couldn't "gravity" just be the effect of differences in time affecting objects?

    That is to say - if 2 objects were floating in space, wouldn't the differences in time make them start moving toward each other? If ball A and ball B were floating in space like so:

    A B

    Ball A would experience slower time on the side which is closest to ball B. And ball be would experience slower time on the side which is closest to ball A. Wouldn't that make them accelerate toward one another, thus giving the illusion that they are "attracted" to each other?

    I think there's a general consensus that gravity creates changes in time, what if we got it all backwards, what if it's time that creates the appearance of gravity?
  2. jcsd
  3. Mar 17, 2009 #2


    Staff: Mentor

    That is correct. For two objects at rest only the curvature in the time direction is important.
  4. Mar 17, 2009 #3


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    Science Advisor

    Does it really make sense to ask what causes what here? Gravity and gravitational time dilation are observed phenomena. While curved spacetime (with emphasis on time) is a mathematical model, that can be used to describe them. In the domain of that model, you could say that curved time causes both of them:
  5. Mar 17, 2009 #4
    I think it does. I keep hearing about Quantum Physicists looking for a Quantum Theory of Gravity, if Gravity is an effect of Time, why aren't they looking for a Quantum Theory of Time? :) Semantics, maybe ... but there's a difference to me.

    I also loathe the word "curvature".
    Pictures like this drive me nuts because you can't draw one picture in this manner to show how gravity works from all directions.

    I'll get back to my thinking, thanks for the replies.
  6. Mar 17, 2009 #5


    Staff: Mentor

    Your personal feelings about the English don't change the math.
  7. Mar 18, 2009 #6


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    Well, they could have called it warping, instead introducing two types of curvature (extrinsic, intrinsic).
    This picture doesn't show how gravity works at all. For sensible visualizations follow the links in this post:
  8. Mar 18, 2009 #7
    Good grief. I'll keep posting stupid statements, love the info. Thanks!
  9. Mar 18, 2009 #8

    Your line of thought is very intriguing.

    Your approach would even work for space point particles. An electon might not occupy a spatial volume, but its wave function suggests that it occupies a volume of space in a stochastic manner. So when it "might" be closer to a neighbouring object its influence of gravity and time dilitation would be greater than other moments when it is probabilistically farther away. Thus, your principle might still be applicable to such particles.
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