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Dark Flow

  1. Sep 12, 2010 #1
    How does dark flow work? Thanks
     
  2. jcsd
  3. Sep 13, 2010 #2
    It probably is just an artifact of imagination and the imagery taken. I personally don't believe that it exists.
     
  4. Sep 13, 2010 #3
    A prove that there is another universe which pulls our universe apart by gravity. Dark matters are actually matters in another universe which explains why it has not been detected so far?
    "Big bang" might actually be a "big pull" - empty space being torn apart fby another universe. The universe may actually be infinite. Tear and crunch are actually manifestations of different components of the "whole"
     
  5. Sep 13, 2010 #4
    Yeah, it's a HUUUUUUGE might, that is more popsci than science.
     
  6. Sep 13, 2010 #5
    thanks for answering
     
  7. Dec 21, 2010 #6
    If true Dark Flow could be one of the most important observations since the CMBR. Looking forward to hearing the latest updates on this discovery. For one thing it would change our views a little on a homogenious and isotropic universe at different scales.


    http://www.sciencedaily.com/releases/2010/03/100310162829.htm

    http://en.wikipedia.org/wiki/Dark_flow

    http://www.kashlinsky.info/anima/skash.nsf/home?OpenForm



    "We now summarize the main conclusions from this study:

    • Our measurements indicate the existence of the residual CMB dipole evaluated over
    the CMB pixels associated with the hot SZ producing gas in clusters of galaxies. The dipole
    is measured at high-signifance level (∼ 8σ in the outer bins) and persists out the limit of
    our cluster catalog zmedian 0.1. Its direction is not far off the direction of the ”global CMB
    dipole” measured from the entire unprocessed maps.

    • We show with detailed simulation that the CMB mask and/or cluster sample discreteness
    induced cross-talk effects are negligible and cannot mimic the measured dipole.

    • The dipole originates exclusively at the cluster pixels and, hence, cannot be produced
    by foregrounds or instrument noise. It must originate from the CMB photons that have
    passed through the hot gas in the catalog clusters.

    • We prove that the signal arises from the hot SZ producing cluster gas because we
    demonstrate that in the unfiltered CMB maps there remains statistically significant temperature
    decrement as expected from the TSZ effect. Its profile is consistent with the NFW
    profile out the largest aperture where we still detect hot gas (∼ 30). At larger radii the
    dipole begins to decrease as expected.

    • In the filtered maps, designed to reduce the cosmological CMB fluctuations, the dipole
    is isolated simultaneously as the monopole component vanishes. This proves that its origin
    lies in the KSZ component. The monopole vanishes (within the noise) because for the
    NFW profile the gas in hydrostatic equilibrium must have a strong decrease in the X-ray
    temperature in the outer parts. This decrease is consistent with the available direct X-ray
    measurements, but more importantly is demonstrated empirically in AKKE.

    • With the current cluster catalog we determine that the amplitude of the dipole corresponds
    to bulk flow of 600-1000 km/sec. This conversion factor, C1,100, may however
    have some systematic offset related to our current cluster modelling. However, this possible
    uncertainty only affect the amplitude of the motion, not its coherence scale or existence.

    • The cosmological implications are discussed in Kashlinsky et al (2008). We show
    there that the concordance ΛCDM model cannot account for this motion at many standard
    deviations. Instead, it is possible that this motion extends all the way to the current cosmological
    horizon and may originate from the tilt across the observable Universe from far away
    pre-inflationary inhomogeneities (Kashlinsky et al 1994; Turner 1991)."


    I suggest they prove their method by looking in a few other directions to see if there are other dark flows or if this a unique one off event.
     
    Last edited: Dec 21, 2010
  8. Dec 21, 2010 #7
    If true a lot of things would blow away previous discoveries... gotta watch out for those big if's.
     
  9. Dec 22, 2010 #8
    Last edited by a moderator: Apr 25, 2017
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