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Magnetic Crunch

  1. Mar 20, 2003 #1
    Assume the universe, after an eventful life doubling our current age, has coalesced all matter into pulsars each with magnetic field of 1014 Gauss. Given the number of pulsars in this observable universe to be 1022, initially distributed homogeneously, at what radius would the expanding (H0=65 km s-1 Mpc-1) universe outstrip the average magnetic attraction between pulsars? In this scenario, might the universe lose its homogeneity over time, or form "magnetic galactic" cores within the forementioned radius?
     
  2. jcsd
  3. Mar 21, 2003 #2

    drag

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    Greetings !

    Why would it do that ?!

    "Does dice play God ?"

    Live long and prosper.
     
  4. Mar 21, 2003 #3
    drag-

    Pulsars are one quite probable end state for stars in our universe, and have an extremely dense quantum magnetic field.

    Even more probable is the nuclear equilibrium that stars evolve eventually into pure iron. (Many pulsars have a 1/2 mile crust of iron!) Remember that purely iron stars would have not nearly as strong ferromagnetic field as pulsars, but would themselves make an interesting substitution into the originally proposed problem.
     
  5. Mar 21, 2003 #4

    drag

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    Greetings !

    Hmm...
    Iron it is, of course.
    However, as I heard (unless the Big Rip or something
    happens before that), by the time that much of the
    Universe becomes iron the CMBR is going to be
    extremely low up the spectrum (with hardly much
    other radiation) and except some huge BH's that
    survive we'll just have iron spread all over.
    Then again, maybe it does follow from it...
    Anyway, aren't the distances going to be too great
    to really effect each other ?

    "Does dice play God ?"

    Live long and prosper.
     
  6. Mar 22, 2003 #5
    drag-

    Remember that ferromagnetic dipoles have in general a much stronger mutual attraction than do their corresponding gravitational masses.
     
  7. Mar 22, 2003 #6

    drag

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    Greetings !

    Hmm... Well, I guess your possibility
    is certainly possible. But, of course that it
    depends upon the way the Universe will evolve.
    If the expansion is indeed accelerated all the
    time then this probably won't be the case.
    I think your enitial question is also complicated
    by the fact that you need a reliable estimate
    about when such pulsars may form.
    (Even if you consider no real changes in the
    Universe across such a large time scale as tens
    of billions of years. And, of course, even now we
    know that H0 is growing.)

    "Does dice play God ?"

    Live long and prosper.
     
  8. Mar 22, 2003 #7
    drag-

    My concern that you raise is whether the cosmological constant/quintessence is great enough always to negate any significant effect by magnetism. Remember that smaller-scale "magnetic galaxies" may still, if temporarily, form under outward acceleration as "gravitational galaxies" formed in Hubble-expansion environment.
     
  9. Mar 22, 2003 #8

    drag

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    Greetings !
    Well, since we have no exact answers from
    cosmology estimates for such time scales
    are a great problem.
    BTW, are you suggesting that magnetic fields can
    "pull" space itself back together ?

    Live long and prosper.
     
  10. Mar 23, 2003 #9
    drag
    Good point. Indirectly, the magnetic interaction affects spacetime by accelerating relatively the masses involved.
     
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