Does the Universe Rotate and Does it Have an Axis?

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    Rotating Universe
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Discussion Overview

The discussion centers on whether the universe itself rotates and if it has an axis, exploring implications of rotation in relation to cosmological principles and the nature of the universe's expansion. Participants engage with theoretical concepts, cosmological models, and the implications of gravity and mass distribution.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants suggest that if everything in the universe rotates, the universe itself should also rotate, questioning what it would rotate around.
  • Others argue that the universe cannot be rotating as a whole, referencing Mach's principle and the absence of a central point in the universe.
  • One participant proposes that if the universe is expanding from a central point, it might also be rotating around that point, though this contradicts the cosmological principle.
  • Another viewpoint emphasizes that the universe is expanding uniformly in all directions, negating the idea of a central point or preferred direction.
  • Some participants discuss the implications of gravitational forces and the concept of a center of mass, suggesting that gravity could lead to orbits if a center existed.
  • There are references to cosmological models, such as the Robertson-Walker metric, which do not allow for rotation due to homogeneity and isotropy.
  • Participants mention the Kerr metric as a rotating solution to Einstein's equations, speculating on its relevance to the universe's structure.
  • Some express uncertainty about the implications of frame dragging and whether it allows for large-scale coupling in the universe.
  • There are discussions about the nature of "nothingness" versus empty space and how this relates to gravitational interactions.
  • One participant references a recent paper suggesting the universe's shape might be a dodecahedron based on background radiation harmonics.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the rotation of the universe, with no consensus reached. Some argue against the possibility of a rotating universe, while others explore the implications of rotation and gravitational dynamics.

Contextual Notes

Limitations include unresolved assumptions about the nature of the universe's expansion, the definitions of rotation and reference frames, and the implications of gravitational interactions in a universe without a defined center.

  • #91
I just wanted to point out that if you are suggesting that the universe is rotating, it must have an axis to rotate on, and thus a center. If the universe has a center, it is spherical in shape and also has a definite size (mass). I recollect that a post earlier in this thread argued that the universe is infinite in size and can not have a center. I believe he or she also mentioned this to be the accepted cosmological model.

Sorry if this has been resolved already or if I'm not referring to what you're referring to. I haven't understood every word thus far (I'm in the 11th grade). Don't bother trying to explain anything to me if it seems I won't get it.
 
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  • #92
Wouldn't it be quite desirable and/or convenient that the universe be rotating - or at least moving - because that would make it much easier to explain the existence of energy?

Respectfully submitted,
Steve
 
  • #93
eah2119 said:
I just wanted to point out that if you are suggesting that the universe is rotating, it must have an axis to rotate on, and thus a center.
Rotation in general relativity doesn't work the way you'd think based on Newtonian intuition. You can have rotation without a center. The FAQ discusses this: https://www.physicsforums.com/showthread.php?t=506988

eah2119 said:
I recollect that a post earlier in this thread argued that the universe is infinite in size and can not have a center.
We don't know if it's infinite in size. We have a FAQ on this too: https://www.physicsforums.com/showthread.php?t=506986
 
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