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B Everything is in motion, what is not?

  1. Feb 3, 2017 #1
    Ok so the planets rotate on their own axis's, in turn, they rotate around the sun, the sun and all our planets combined rotates in turn around the milky way galaxy's black hole, our milkyway galaxy is moving towards the great attractor and now new science confirmed that we are being reppeled by the a great repeller too which all to me is very intriguing. All this is happening at great velocities.

    That tells me there is absolutely nothing that is staionary ? There is nothing that has absolutely no velocity in the universe, is that correct ? And if the nature of the universe and everything in it is to constantly be on the move, what might it tell us about the mechanics of the universe, what would happen if something is stopped to absolute zero velocity, and if space itself is a medium, what would happen if it stops moving as well.
    i can't help but think that without motion, our universe will not work and something will go terribly wrong, to me it seems to be comparable to a gyroscope say on a sateleite, if it stops spinning, it goes out of control.
     
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  3. Feb 3, 2017 #2

    fresh_42

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    Imagine the earth would stop. What does this mean? Can you define it?
     
  4. Feb 3, 2017 #3
    My understanding of physics is limited compared to most here, so please correct me if I'm wrong. But I was under the impression that velocity is relative and so, unless absolutely EVERYTHING stops moving, something will never have "absolute zero" velocity.
     
  5. Feb 3, 2017 #4

    PeroK

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    There is actually no such thing as absolute velocity, only velocity relative to other objects. You cannot put a definite value, for example, on the Earth's absolute velocity; only its velocity relative to the Sun or the Milky Way centre, or the Andromeda Galaxy or whatever.

    That said, there is nowhere you can escape the gravity of something. So, in a sense, everything is constantly changing its velocity relative to everything else. And, because of gravity you cannot effectively have static equilibrium on a cosmic scale.

    Added to this there is the expansion of space itself, which results in the constantly increasing distance over time of objects separated by significant cosmic distances.
     
  6. Feb 4, 2017 #5
    I guess i'm just trying to dig deeper on whats already known about the universe, we know the universe won't work to create our reality if there is no constant motion, and if there is no gravity and vacuum.

    i guess i'm just trying to understand it from a 3rd person perspective "outside" the universe, the true origins of gravity for one albeit still speculation is that gravity may originate from outside our universe, and why is space mainly in vacuum form "we live in a black hole theory" explains it best so far for myself, impossible questions but just thinking about it a lot, thanks i guess Perok confirmed a few points..
     
  7. Feb 4, 2017 #6

    russ_watters

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    No, it isn't. I am stationary. Why? Because I said so. That's the Principle of Relativity - invented by Galileo - in action.
     
  8. Feb 4, 2017 #7

    phinds

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    There is no such thing, not even as a thought experiment.
     
    Last edited: Feb 4, 2017
  9. Feb 5, 2017 #8

    Chronos

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    Since the 'universe', by definition, includes everything that ever has and ever will exist getting outside the universe is like trying to get outside of yourself.
     
  10. Feb 5, 2017 #9

    Chronos

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    Edit. Cosmologists like to use what is known as the CMB rest frame as a reference standard. Under that scheme, our galaxy, is cruising along about 600 km/sec in the general direction of the constellation Hydra [as viewed from earth]. The solar system, which is orbiting the center of the galaxy, is moving about 225 km/sec along a line stretching from the star Sirius and towards the star Vega. Not to worry, no star wrecks loom in our future, Sirius and Vega are heading pretty much in the same direction we are.
     
  11. Feb 6, 2017 #10
    What if he wants to observe it from a different universe? The multiverse theory is a real theory. The OP's question is not unworthy of being discussed as a thought experiment.
     
  12. Feb 6, 2017 #11

    phinds

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    If there are other universes they are not in causal contact with this one so yes, it IS unworthy of being discussed since it is meaningless.
     
  13. Feb 6, 2017 #12

    Chronos

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    The multiverse is a theory intrinsically incapable of being falsibied. Labeling it causally disconnected merely guarantees it will never offer any testable predictions.
     
  14. Feb 7, 2017 #13
    It was Einstein's fundamental insight that there is no absolute reference frame. His entire theory is based on the idea that there is no such thing as a zero reference for velocity and motion and the only fixed thing is the speed of light in a vacuum. Go read up on the Theory of Relativity for more understanding. It will take quite a bit of work to get your head around it a little, at least it did for me. There are no easy answers to this. It is a fundamental question.
     
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