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The spinning universe

  1. Jun 22, 2008 #1

    PhanthomJay

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    Ok, so the earth spins around its axis, and around the sun; and the sun spins around the black hole at the center of the Milky Way galaxy; and that center spins around some other monster black hole at the galactic center of a cluster of galaxies, which, in turn spins about another monster monster black hole at the center of the center of the cluster of glaxies, etc. etc., and all this spinnning makes me dizzy. QUESTION: Ultimately, does the spinning end? Is there one mother of all black holes? It would seem that if not, then there must be an infinite number of black holes in an infinite universe.
     
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  3. Jun 22, 2008 #2
    General relativity theory does not exclude the possibility of a spinning universe. But I do not think we know if that is actually the case in our universe.
     
  4. Jun 23, 2008 #3

    PhanthomJay

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    Thanks. I see universes rotating about universes, and so forth, to infinity, but since this is just speculation, let's drop it right here. Thanks.
     
  5. Jun 23, 2008 #4
    I don't believe there is any evidence for the Milky Way, or any other galaxy in the local group, being influenced by another external, central, supermassive black hole.

    What you are asking, if I'm not mistaken, is that the universe has a preferred direction and that the matter within the universe has a net angular momentum. Certainly, If there was a central "monster monster" black hole at the "center of the center", then that might indicate there is a direction and angular momentum.

    I believe the current LambdaCDM model doesn't rely on either and actually precludes either direction or angular momentum.

    If you are asking if the Universe, as a whole, spins... I would ask in relation to what does it spin and how could we recognize it?
     
  6. Jun 24, 2008 #5
    A spinning structure can be truly symmetrical only in two of the three spatial dimensions. Specifically in the two dimensions of its equatorial plane of rotation (i.e., orthogonal to its rotation axis.)

    I think a spinning observable universe (whether or not the entire universe is spinning) would be detectable due to the anisotropy of the matter distribution and the recession velocity biased in the general directions pointed by its rotation axis. Think of it as the Newtonian centrifugal and Coriolis pseudo-forces in action, distorting the otherwise symmetrical collapse action of gravity. Of course if the angular velocity of rotation is very slight, the effect might be too small to detect. Some rotational shear might also be detectable, with the most distant galaxies all appearing to move consistently in a retrograde direction relative to nearby galaxies, due to their differing orbital periods.

    If the universe is expanding, then my guess is that the angular momentum of the spin would constitute a form of peculiar motion which would be diluted over time by the Hubble expansion, at the rate of 1/a (with a being the scale factor of the observable universe). If the universe were static, then it seems possible for the spin to be quite stable if it is already in virial equilibrium (although it seems impossible that enough time has elapsed since the big bang for particles which are too far apart to be in causal contact with each other to gravitationally synchronize their motions). In that case, over time the spin would be defeated only by the perturbative effects of gravity waves and collisions and near-collisions between massive objects, which nudge or toss them out of the symmetrical spin pattern, resulting in chaotic motion.

    I note that since a rotating universe requires a unique axis of rotation, which could be thought of as the linear "center of the universe", it would violate some people's notion of a strong cosmological principle.

    Jon
     
    Last edited: Jun 24, 2008
  7. Jun 27, 2008 #6

    PhanthomJay

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    My assumption was that the Milky Way Galaxy, and other galaxies of the local group, are rotating as a whole, and perhaps with other clusters of galaxies, around some 'entity' or supermasive black hole at the center of the rotation. You are saying that this is an incorrect or unproven assumption?
     
  8. Jun 27, 2008 #7

    Chronos

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    A spinning universe would be observationally detectable. No credible observational support for this conjecture has yet been detected.
     
  9. Jun 28, 2008 #8
    http://content.answers.com/main/content/wp/en-commons/2/2f/Local_Group.JPG

    Yes I'd say that was incorrect. Take a look at a map of our local group, and note the massive expanses of millions and millions of light years of nothingness inbetween the galaxies. I guess you are assuming gravity would be the overriding force, but, correct me I'm wrong, the expansion of space has meant these galaxies are just too spread out for them to all be orbiting each other.

    Thats not to say some clusters and galaxies that formed from nearby nebulas can and do gravitationally lock, merge together or orbit supermassive blackholes.
     
  10. Jun 28, 2008 #9
    There are large structures which are gravitationally bound and may be in virial equilibrium (that is, they have settled into a constant rotation rate). These are galaxy clusters. Rich galaxy clusters may contain up to thousands of galaxies within a fairly small radius. The majority of the mass in galaxy clusters does not come from the galaxies, it comes from a dense cloud of hot gas and dust (and of course is dominated dark matter) which is referred to as the intracluster medium.

    Observationally it is obvious that our MW galaxy is not located in such a galaxy cluster. Our galaxy is paired with the Andromeda galaxy and a few miniature galaxies which collectively are called our Local Group. Its radius is not much less than that of a galaxy cluster, which illustrates how much difference there is in the density of our galactic neighborhood compared to those clusters.

    Our Local Group in turn is considered to be part of a much larger collection of galaxies, galaxy groups, and galaxy clusters, called the Local Supercluster. However, recent observations indicate that superclusters are not gravitationally bound structures, in the sense that each supercluster is expanding, probably at an accelerating rate.

    Jon
     
    Last edited: Jun 28, 2008
  11. Jun 28, 2008 #10
    Good explanation Jon. I just read all the galaxies in our local group (but prob not local supercluster) display blueshift (approach... or rotation?), whereas (nearly) all the other observable galaxies/objects display redshift.
     
  12. Jun 28, 2008 #11
    Hi Blueprint,
    Yes, the overall blueshift of the Andromeda galaxy indicates that it is moving toward us at about 300 km/sec. Most of the dwarf galaxies in the Local Group are considered to be "companions" of MW or Andromeda, being gravitationally bound and in orbit around one or the other. The Triangulum galaxy, the 3rd largest galaxy in the group, is believed to be a companion of Andromeda.

    If a galaxy is reasonably nearby and is large enough, and is situated mostly edgewise to us, we can detect that one edge is more redshifted (or blueshifted) relative to the other edge, which enables an estimate of the galaxy's rotation speed.

    Jon
     
  13. Jun 29, 2008 #12

    Chronos

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    Sounds like a theory in the making. Please elaborate the one you have in mind along with observational evidence.
    .
     
  14. Jun 29, 2008 #13
    Hi Chronos,
    I assume your request is directed to PhantomJay, not me.

    Jon
     
  15. Jul 1, 2008 #14

    George Jones

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    Friedmann-Robertson-Walker universes don't have spin, but it is possible to have universes that have non-zero vorticity tensors. Godel came up with a spinning universe model more than fifty years ago. His model: has closed timelike curves; has no observational basis.

    A few months ago, media reported preliminary observational evidence for a preferred sense of rotations of galaxies. Further statistical analysis by the same group indicates that these reports were premature, and that there is no statistical evidence for a preferred sense of rotation.
     
  16. Jul 1, 2008 #15
    Really?! This goes against everything I have heard or read....or was that just a poor choice of words? Did you mean receding from us?

    Also, I have heard that our local group is migrating towards the local supercluster. If this is so, why would that light be redshifted?

    If my assumptions are incorrect, please correct me. :)
     
  17. Jul 1, 2008 #16
    Hi George,
    It's an informative study about tabulating individual galaxy spins, but of course the authors do not suggest that a slight statistical imbalance of galaxy spins to clockwise or counterclockwise in one or two regions of space as viewed from earth would have any connection to whether the cosmic matter field as a whole is spinning. Most likely if it occurred it would be attributable to local effects such as magnetic fields or gravitational collapse mechanics.

    Jon
     
  18. Jul 5, 2008 #17
    A spinning of the universe as a whole would showup as an accelerated expansion.
     
  19. Jul 6, 2008 #18
  20. Jul 18, 2008 #19

    PhanthomJay

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    I don't have any evidence, I just 'feel' that since stars rotate about black holes at the center of galaxies, then (logically?) one might assume that galaxies rotate about black holes at centers of clusters of galaxies.
    I do have another question: I believe I read somewhere that the distant galaxies are moving away from us, at an accelerating rate, due to spacetime expansion, but that the galaxies themselves are actually 'stationary' with respect to us, that is, their apparent recession speed from us, at or beyond the speed of light, is due entirely to spacetime expansion and not due to actual movement of those galaxies at some velocity with respect to space. Comment??
     
  21. Jul 18, 2008 #20
    Could you provide a source for your claim?
     
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