Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Starkman tinkers with MOG (relativistic MOND)

  1. Jun 11, 2006 #1

    marcus

    User Avatar
    Science Advisor
    Gold Member
    2015 Award
    Dearly Missed

    http://arxiv.org/abs/gr-qc/0606039

    for something to gain visibility all it needs is people interested in proving or disproving it. It doesnt need people to BELIEVE it.
    Some PF members seem not to have heard of RELATIVISTIC MOND. Or else they may be positive that MOND does not do lensing.

    I have had people tell me that MOND is not relativistic, and also that it does not imitate the gravitational lens effects of dark matter. Maybe it is a confusion of terminology.
    Maybe relativistic MOND should be called "MOG" for "modified gravity"
    instead of the old term which is associated with Moti Milgrom's 1981 crude unrelativistic initial version.

    Anyway, I think we should be watchful of the process of relativistic MOND, like Bekenstein's TeVeS "mog" and like John Moffat's "mog" gaining credibility and interest.

    For example Glenn Starkman has coauthored papers with Lawrence Krauss and with Neil Cornish, and also with Spergel. Now here he is tinkering with TeVeS.

    I have to go out, be back later. Not sure what this means to me but looks like "mog" is getting less marginal. Moffat just had a paper where it takes care of BOTH galaxy rotation curves and Pioneer anomally and makes testable predictions for probe signals within the solar system (so not too expensive to test)

    from a QG perspective, the thought would be that if mog is right as an effective theory it may have a reasonable or nice explanation at quantum level. only the effective theory is then awkward, maybe.

    have to go so edit later
     
  2. jcsd
  3. Jun 12, 2006 #2

    wolram

    User Avatar
    Gold Member

  4. Jun 12, 2006 #3

    marcus

    User Avatar
    Science Advisor
    Gold Member
    2015 Award
    Dearly Missed

    That is a good find! HongSheng Zhao is major-league (IoA Cambridge, over 50 published papers) and at present intensely involved with testing TeVeS relativistic MOND, as well as the older classical-type MOND.

    Here is a sample from the abstract of the paper you cited:

    "...we develop orbits and gravitational lensing of the models in non-spherical geometries. In particular, we can generate a multi-centred baryonic system with a weak lensing signal resembling that of the merging galaxy cluster 1E 0657-56 with a bullet-like light distribution. We finally present analytical scale-free highly non-spherical models to show the subtle differences between the single field classical MOND theory and the multi-field TeVeS theory."

    this helps to make an idea mainstream, when people like Zhao get interested and when young people realize that career-wise it is a good area to do research. Just to give an idea of Zhao's activity here is a list of his most-recent half-dozen papers:


    1. astro-ph/0606216 [abs, ps, pdf, other] :
    Title: Can MOND take a bullet? Analytical comparisons of three versions of MOND beyond spherical symmetry
    Authors: Garry W. Angus, Benoit Famaey, HongSheng Zhao
    Comments: 14 pages, 9 figures, accepted for publication in MNRAS

    2. astro-ph/0512425 [abs, ps, pdf, other] :
    Title: Refining MOND interpolating function and TeVeS Lagrangian
    Authors: HongSheng Zhao, Benoit Famaey
    Comments: accepted for publication in ApJ Letters
    Journal-ref: Astrophys.J. 638 (2006) L9-L12

    3. astro-ph/0511754 [abs, ps, pdf, other] :
    Title: Roche Lobe Shapes for testing MOND-like Modified Gravity
    Authors: HongSheng Zhao, LanLan Tian
    Comments: 11p, 7 figs, accepted for Astronomy and Astrophysics

    4. astro-ph/0511713 [abs, ps, pdf, other] :
    Title: Roche Lobe Sizes in Deep-MOND Gravity
    Authors: HongSheng Zhao
    Comments: 4 pages, 2 figures, Astronomy and Astrophysics Letter, in press

    5. astro-ph/0509590 [abs, ps, pdf, other] :
    Title: Testing Bekenstein's Relativistic MOND gravity with Lensing Data
    Authors: HongSheng Zhao, David J. Bacon, Andy N. Taylor, Keith Horne
    Comments: reduced to 17p, 16 figs, discussed cosmology and constraints on mu-function, MNRAS accepted
    Journal-ref: Mon.Not.Roy.Astron.Soc. 368 (2006) 171-186

    6. astro-ph/0508635 [abs, ps, pdf, other] :
    Title: A review on success and problem of MOND on globular cluster scale
    Authors: HongSheng Zhao
    Comments: to appear in IAU Col. 198, Helmut Jerjen and Bruno Binggeli eds

    Zhao has co-authored with Joe Silk and Martin Rees and David Spergel.
    I want to repeat something. I think it doesn't matter if someone of Zhao stature BELIEVES your model. He is a prominent observational astronomer and they are supposed to TEST models, not believe in them. What matters is that Zhao and others like him seriously want to test and compare your model against the usual DARK MATTER notion and against other MONDs.

    If I was John Moffat or Jacob Bekenstein I think I might be celebrating. It is great to see the observational people get seriously interested in TeVeS (or relativistic mond, or whatever you call it)
    ==========

    Wolram, since I can still edit I will respond to your next post (#4) here: I dont know of a typical MOND candidate. I have seen papers that show some 20-50 graphs of the rotation curves of numerous galaxies with the mond prediction and the darkmatter prediction fitted to them. To show that the MOND rotation curve typically fits better. What I have NOT seen is a playoff between vintgage 1981 Milgrom MOND and the more recent relativistic MOND. I think that one could probably not see any difference in rotation curves, but I dont know for sure. I think the difference would only show up when you look at LENSING. Otherwise it would likely be a small percentage. Maybe someone else knows something more definite. thanks for flagging that HongSheng Zhao paper. I didn't know about his work.
     
    Last edited: Jun 12, 2006
  5. Jun 12, 2006 #4

    wolram

    User Avatar
    Gold Member

    I imagine this (skew tensor) is not much, may be like rounding a million $ to
    the nearest cent, my question is, is it observable, is there some structure
    (galaxy) that is a typical mond candidate?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Starkman tinkers with MOG (relativistic MOND)
  1. MOND principle (Replies: 7)

  2. Mond Vs Dark Matter (Replies: 10)

Loading...