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Existence of dark matter questioned

  1. Feb 14, 2004 #1

    wolram

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    http://physicsweb.org/article/news/8/2/4

    6 February 2004

    Many astronomers believe that the universe is dominated by cold 'dark matter' and 'dark energy' - a view that has been confirmed by recent measurements on the cosmic background radiation. Now, however, a group of astrophysicists in the UK has found that this radiation - the microwave 'echo' of the big bang - may in fact have been modified or 'corrupted' as it passed through galaxy clusters on its way to Earth. The result could undermine previous evidence for both dark matter and energy (Monthly Notices of the Royal Astronomical Society

    http://arxiv.org/abs/astro-ph/0306180
     
    Last edited: Feb 14, 2004
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  3. Feb 15, 2004 #2

    wolram

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    http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/287mlhdf.asp

    Ninety percent of the universe and the majority of mass in galaxies are accused of being made of a mysterious and unseen material known as dark matter. But a team of astronomers from Australia, Italy, the Netherlands, and the United Kingdom have undertaken the first search for dark matter in elliptical galaxies and come up empty-handed.
     
  4. Feb 15, 2004 #3

    marcus

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    a preprint that goes with this article in "Astronomy"
    is
    http://arxiv.org./abs/astro-ph/0310874

    it is by Michael Merrifield and Aaron Romanowsky, two of those quoted by the "Astronomy" report.

    ----------
    wolram, how much bother would it be for you to collect all the links
    challenging the dark matter hypothesis into this one thread?
    Have you got so many that it would be too much work?
    If so you could be selective and just put the links to the most recent, or to what you find the most convincing.
    -------------

    Nereid has a bunch of evidence (links) supporting dark matter. One could kind of line it up and compare.

    this merrifield/romanowsky article (from U. Nottingham I think) is
    straightforward enough---they found planetary nebulas around ellipticals moving slower, the further out they were.

    it is already pretty good to be able to see the out-lying blobs like gnats around the Big Mother Elliptical
    and they used a special new device that not only can
    discern the blobs but apparently can estimate how fast they are moving. a new "planetary nebula" spectroscope.

    this doesnt stop the argument but it does score points

    what else do you have?
     
    Last edited: Feb 15, 2004
  5. Feb 15, 2004 #4

    wolram

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    Astron. Nachr./AN 32X (200X) X, XXX–XXX
    arXiv:astro-ph/0311607 v1 27 Nov 2003
    Toward a detailed view on the kinematics of intermediate
    luminosity early-type galaxies no dark matter candidates
    G. COVONE1 AND N. R. NAPOLITANO2
    1
    Laboratoire d’Astrophysique de Marseille, traverse du Siphon, 13012 Marseille, France
    2
    Kapteyn Astronomical Institute, Landeleven 12, Post Office Box 800, 9700 AV Groningen, the Netherlands
    Received date will be inserted by the editor; accepted date will be inserted by the editor
    Abstract. In several nearby L  L* early-type galaxies, recent observations at large radii have shown a indications of a lack
    of dark matter, substantially at odds with the prediction from the Cold Dark Matter (CDM) hierarchical merger models. Here
    we discuss a pilot observational project for the study of the internal kinematical and dynamical properties of this remarkable
    sample of galaxies.
     
  6. Feb 15, 2004 #5

    wolram

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    marcus.
    the evidence for dark matter vastly outweighs the
    evidence for no dark matter to date, i will use only
    the papers from "respected" sources and post them.
     
  7. Feb 15, 2004 #6

    marcus

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    I wish we had Nereid's advice on this.
    it seems like a good thing to do (to me)
    unless there are so many articles that it would be
    a lot of bother for you to list them.
    but I am curious as to what she would say.

    I know your sources are legitimate scientist
    sources---that's what I am used to seeing from you---
    and they do make the most credible evidence (even if the other
    ones can occasionally be right too)----so that is not the
    issue
     
  8. Feb 15, 2004 #7

    wolram

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    arXiv: astro-ph / 0309823 30 Sep 2003
    Errors in equations for galaxy rotation speeds
    Kenneth F Nicholson, Caltech Alumni
    knchlsn@alumni.caltech.edu
    nd364m@aol.com
    Abstract
    Shown are the errors and difficulties of the equations used for galaxy rotation speeds in the book
    "Galactic Dynamics" (Binney and Tremaine). A usable and accurate set of equations is then presented.
    The new equations allow easy determination of galaxy mass distribution from the rotation profile with no
    need for dark matter or any knowledge of galaxy surface light.
    -------------------------------------------------------------------
    i can not comment on this on, maybe you math people
    can?
     
  9. Feb 15, 2004 #8

    wolram

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    http://star.arm.ac.uk/nam2003/Press/press_nam18.html

    An international team of astronomers has discovered that "dark matter", the mysterious material that seems to make up most of the mass of galaxies, is not as all-pervasive as previously believed. Surprising new results from studies of several elliptical galaxies show they are not surrounded by halos of dark matter as was expected. The findings will be presented at the UK/Ireland National Astronomy Meeting in Dublin on Wednesday April 9th by Dr Aaron Romanowsky of the University of Nottingham.
     
  10. Feb 15, 2004 #9

    wolram

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  11. Feb 15, 2004 #10

    wolram

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    as you say marcus, on the surface its six of one and
    half a dozen of the other, but dark matter and
    dark energy opened up a hole new area for research,
    lots more to wright about and mysterious to boot.
     
  12. Feb 16, 2004 #11
    There has been a lot of speculation about Dark Matter/Dark Halo's over the past number of Years.

    The usual Hubble Classification of Galaxies (I may be incorrect, long time since I read up on it), but I think it goes like this:

    Elliptical Galaxies >E0-E3-E7 for instance? The first order of E0 are highly Spherical(not flat) and have a High luminosity rating, and therefore the Dark Matter is based on Galaxies being squeezed/flattened by the lack of Light(luminosity) as a Galaxy grows old/ages, the Luminosity of a Galaxy becomes 'DARK' over time.

    I remember sending NASA 'ask an astronomer' a question based on my observation that all E0 galaxies were not flattened by the Space that surrounds them, and was inquiring to if there was a LUMINOSITY correlation to the existence of Dark Matter and Luminosity, Highly luminous Galaxies have a lot of Photons pouring out from them, so they have a lot of WHITE-BRIGHT-MATTER emminating around them.

    There reponse I got was:Thats interesting!..nobody had asked that question before?

    As galaxies aged they become Spiral and Barred out, they also become flat as the 'Darkness' increases because of the Luminosity diminishing, they in effect get Squashed more by the Vaccum of Space(a highly luminous Galaxy produces opposing pressure to collapse).

    This of course is based on a number of other paramiters and is my personal take on Dark Matter/Energy Evolution.
     
  13. Feb 16, 2004 #12

    wolram

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  14. Feb 16, 2004 #13

    wolram

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    ranyart.

    There reponse I got was:Thats interesting!..nobody had asked that question before?
    -------------------------------------------------------------------
    an amazing admission from nasa
     
  15. Feb 16, 2004 #14

    wolram

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    http://arxiv.org/abs/astro-ph/9407019

    We re-examine the systematic errors in the determination of the primordial helium abundance, $Y_{\rm P}$. We find that the systematics are significantly larger than the statistical errors. The uncertainty in (the determination of) $Y_{\rm P}$, is thus, larger than is currently claimed. Furthermore, most of the systematics lead to underestimate of $Y_{\rm P}$. The new upper bound allows cosmological models with no non-baryonic dark matter in which $\Omega_{baryons} = \Omega_{BBN} = \Omega_{dyn}$.
     
  16. Feb 16, 2004 #15

    wolram

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    http://www.aeiveos.com/~bradbury/Astronomy/MOND.html

    A modification to the standard model of Newtonian Dynamics has been proposed to resolve the problem of the missing Dark Matter.
    ----------------------------------------------------------------------------
    http://nedwww.ipac.caltech.edu/level5/Ashman2/Ashman4_3.html
    Throughout this Section it has been assumed that stellar velocity dispersions reflect the gravitational potential of a system in virial equilibrium, so that velocities exceeding those that can be explained by the visible mass in dwarf spheroidals are interpreted as evidence for DM. There are two possible ways of avoiding this conclusion that have been discussed in the literature. The first is the suggestion by Milgrom (1983) and others that at low accelerations Newtonian gravity breaks down. Since this suggestion has implications for all types of galaxies I defer a discussion until Section 11.
     
  17. Feb 16, 2004 #16

    wolram

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    http://www.gsfc.nasa.gov/topstory/2004/0107filament.html

    "To explain our results," said Francis, "the dark matter clouds that lie in strings must have formed galaxies, while the dark matter clouds elsewhere have not done so. We've no idea why this happened - it's not what the models predict."
     
  18. Feb 16, 2004 #17

    wolram

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    http://physicsweb.org/article/news/04/10/3

    Two years ago, the Boomerang experiment photographed with unprecedented accuracy fluctuations in the temperature of the microwave background - the radiation left over from the big bang - in a patch of sky at the South pole. As expected, the results revealed a peak consistent with a 'flat' universe that has just enough energy to continue expanding forever. As expected the Boomerang team also detected a second peak, but it was considerably smaller than predicted. A possible explanation of this finding is that there might be twice as much baryonic material in the universe as has been detected so far, and that it could be hidden inside galaxies.
     
  19. Feb 16, 2004 #18

    wolram

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    http://arxiv.org/abs/astro-ph/0401398

    Newtonian mechanics indicates that galaxies and galaxy clusters are much more massive than we would have guessed from their luminosities, with the discrepancy being generally attributed to dark matter halos. An alternative hypothesis is that accelerations in very weak gravitational fields are larger than predicted by Newton's laws, and there is no need for dark matter. Even though we do not currently have a satisfactory theory associated with this rival hypothesis, we can ask whether any observational tests could rule it out or prefer it over the dark matter hypothesis. Current evidence suggests that neither hypothesis enjoys a decisive advantage over the other. If dark matter turns out to be the correct interpretation however, then theories of galaxy formation face some quite severe fine-tuning problems.
     
  20. Feb 16, 2004 #19

    wolram

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    i have attempted to give a background to my skepticism
    for dark matter, especially (non baryonic) the papers i have posted
    may only scratch the confidence of people that believe in
    its existence, but i am far from concluding it is a
    reality, if anyone has a contribution to this thread
    it would be most welcome.
     
    Last edited: Feb 16, 2004
  21. Feb 16, 2004 #20

    wolram

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    posted by MARCUS.

    I wish we had Nereid's advice on this.
    -------------------------------------------------------------------
    i am in total agreement, if anyone has an explanation for
    the negative or null resuls for DM i expect it would be
    NERIED.
     
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