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Gaping hole found in universe

  1. Aug 24, 2007 #1
  2. jcsd
  3. Aug 24, 2007 #2
  4. Aug 25, 2007 #3

    Chronos

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    The inability to detect dark matter without visible light sources in the vicinity is not surprising. Is the void a 'pocket' of empty space, or a zone empty beyond observational limits? How large is this region compared to the observable universe at the same scale? What is it's CMB temperature? I'm not convinced this is a compelling observation.
     
  5. Aug 25, 2007 #4
    Does the void means a part of the space where there's no matter, planets or stars? The source for this observation seems rather vague.
     
  6. Aug 25, 2007 #5
    Great cosmic nothing

    Astrnomers, have found a great cosmic nothingness which as I understood from the link below is considered as an evidence of dark energy.
    http://news.bbc.co.uk/2/hi/science/nature/6962185.stm
     
    Last edited: Aug 25, 2007
  7. Aug 25, 2007 #6

    marcus

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    Good find!
    Here is an earlier paper about this
    http://arxiv.org/abs/0704.0908

    Your BBC article has new information. This article is a previous one by Rudnick who was quoted in the BBC article

    In case anyone is interested here is the space.com piece on it as well
    http://www.space.com/scienceastronomy/070823_huge_hole.html

    I think this finding is consistent with standard cosmology. At least as Rudnick presents it, what it does is demonstrate the Sachs-Wolf effect and (more generally) the presence everywhere of dark energy---equivalently a small positive cosmological constant Lambda.

    Light passing through clusters of galaxies picks up energy by the socalled Integrated Sachs Wolf mechanism
    and that partly offsets the inevitable LOSS of energy due to expansion of distance, which lengthens wavelengths.
    Because of expansion, light traveling over cosmological distance is getting COLDER on average, but by passing thru clusters of matter it picks up a little energy so it doesnt come off so cold. If it goes for a very long time without passing thru any crowds of galaxies----in this case the void is a billion lightyear across---then it reaches us unusually cold. They saw a cold spot on the CMB temperature map and figured that it might be due to a void, so they looked for the void and there it was.

    I think it tends to confirm the standard picture----which not all the news does these days: there have been some surprises, like the MAGIC result about gammaray going different speeds (see the IACT thread)
    https://www.physicsforums.com/showthread.php?t=181602
     
    Last edited: Aug 25, 2007
  8. Aug 25, 2007 #7

    LURCH

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    I notice several articles mention that "voids" have been found before, but none this size. It's much bigger than normal. Nobody's mentioning how big is normal? How much "bigger than normal" is this? Twice as big? A thousand times?
     
  9. Aug 25, 2007 #8

    LURCH

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    Nevrmind; calculated it myself. Southern Local Supervoid; 158Mpc. 1 pc=3.26 ly. 158mpc=474,000,000 ly. The newly-found void is about twice the size of the SLS.

    Is that right?
     
  10. Aug 25, 2007 #9

    marcus

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    Lurch your arithmetic is at least as good as mine
    and I like your detail knowledge in a number of areas :approve:
    Looks right to me!
     
  11. Aug 26, 2007 #10

    hellfire

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    Have to find the reference but I read somewhere that the probability for such a void in LCDM is under 10^-5. IIRC there is a recent work of Peebles about void distributions. Anyway, one should be careful inferring about cosmological models based on single observations.
     
  12. Aug 26, 2007 #11
    Yeah it does seem very vague, I was hoping someone else had heard more about it...
     
  13. Aug 26, 2007 #12

    Haelfix

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    I'm rather intrigued by this, as I know people who work on structure formation are quite busy thinking about this atm.

    I don't think the full details have been made public yet, so we have to wait for the paper.
     
  14. Aug 26, 2007 #13
  15. Aug 26, 2007 #14

    hellfire

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    Well, it is actually mentioned in the paper :rolleyes::

    Therefore they conclude:
     
  16. Aug 26, 2007 #15

    arivero

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    It is http://arxiv.org/abs/0704.0908

    Extragalactic Radio Sources and the WMAP Cold Spot
    Authors: Lawrence Rudnick, Shea Brown, Liliya R. Williams
     
  17. Aug 27, 2007 #16

    Chronos

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    Thanks for the link, Brad. The void appears to be explicable without invoking ATM physics. It is, however, an interesting observation that merits further study. The fundamental question is whether this an example of new physics, or an unforeseen interaction within the bounds of existing physics. I admittedly lean toward the unforeseen side of existing physics.
     
    Last edited: Aug 27, 2007
  18. Aug 27, 2007 #17
    could this hole or void be paint in the picture of axis of evil (fimngers of god) story be present in the work where of Joào Magueijo. He is working on this am i wright ?..
     
  19. Aug 27, 2007 #18

    NoTime

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    They have said how wide the void is.
    I'm curious about how deep it goes or is there any data on this?
     
  20. Aug 28, 2007 #19
    emanaly
    Does the "cold spot" relate in any way (like in its geometry) to the previously discovered "warm spot" other than their size, and magnitude of deviation from mean CMB temperature? Can we tell if it or its surroundings are accelerating in expansion? What might be at the center of this void?
     
  21. Oct 9, 2007 #20
    this is hardly a 'hole'. it's just a large region deviod of matter. rare, i'm sure, but it is not a hole.
     
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