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arXiv:1112.3960astro-ph.CO

Modified Newtonian Dynamics (MOND): Observational Phenomenology and Relativistic Extensions

Benoit Famaey, Stacy McGaugh

Early discovery. Linked by one identifiable commenter. This paper is outside the main ranking; a mention is not an endorsement.

Abstract

A wealth of astronomical data indicate the presence of mass discrepancies in the Universe. The motions observed in a variety of classes of extragalactic systems exceed what can be explained by the mass visible in stars and gas. Either (i) there is a vast amount of unseen mass in some novel form - dark matter - or (ii) the data indicate a breakdown of our understanding of dynamics on the relevant scales, or (iii) both. Here, we first review a few outstanding challenges for the dark matter interpretation of mass discrepancies in galaxies, purely based on observations and independently of any alternative theoretical framework. We then show that many of these puzzling observations are predicted by one single relation - Milgrom's law - involving an acceleration constant (or a characteristic surface density) of the order of the square-root of the cosmological constant in natural units. This relation can at present most easily be interpreted as the effect of a single universal force law resulting from a modification of Newtonian dynamics (MOND) on galactic scales. We exhaustively review the current observational successes and problems of this alternative paradigm at all astrophysical scales, and summarize the various theoretical attempts (TeVeS, GEA, BIMOND, and others) made to effectively embed this modification of Newtonian dynamics within a relativistic theory of gravity.

arXiv comments
164 pages, 48 figures, 2 tables, invited review for Living Reviews in Relativity
Journal reference
2012, Living Reviews in Relativity, 15, 10
DOI
doi:10.12942/lrr-2012-10
Subjects
astro-ph.COCosmology and Nongalactic Astrophysics astro-ph.GAAstrophysics of Galaxies gr-qcGeneral Relativity and Quantum Cosmology hep-phHigh Energy Physics, Phenomenology hep-thHigh Energy Physics, Theory

On Hacker News

Linked by 1 identifiable commenter in 12 comments across 10 threads, from Mar 2017 to Aug 2022.

Comments linking this paper, per year.

Discussed in comments10 threads

  1. Dark Matter Doesn't Exist 1 comment

    • Famaey & McGaugh's review <https://arxiv.org/abs/1112.3960> (Stacey McGaugh is <https://tritonstation.com/>, a frequent critic of particle dark matter) §7 is all about adding whole new fields ("parameters") to standard General Relativity in order to capture higher-order terms in…

      raattgiftView on HNParent context

  2. Dark Matter Alternative Passes Big Test 2 comments

    • This is a surprisingly good write-up. The Skordis & Zlosnik paper can be found at https://arxiv.org/abs/2007.00082 I'll start with some comments for non-experts, and then escalate about ten paragraphs further down. tl;dr: there are lots of things that hang on General Relativity…

      raattgiftView on HNParent context

    • > There is something fundamental in the universe that we don't understand. Good! I hope there's lots of fundamental things we don't understand well yet. We can then enjoy improving our understanding. "The paper" below is https://arxiv.org/abs/2007.00082 ==…

      raattgiftView on HNParent context

  3. New dark matter map reveals cosmic mystery 1 comment

    • No, it is unfair to call MOND (and at least much of "the like") as a dark matter theory, because it manifestly generates a solution (or solutions) in the absence of any matter at all. MOND is characterized by an interpolating function between its fundamental constant a_0 and…

      raattgiftView on HNParent context

  4. X17 Particle 1 comment

    • "The relativistic versions of MOND" are just adding fields to General Relativity. Thus making them relativistic theories. Famaey and McGaugh §7. https://arxiv.org/abs/1112.3960 Consequently the rest of your last paragraph is incorrect. "we need dark matter to explain any theory…

      raattgiftView on HNParent context

  5. Dark Matter Sighting Gets a Reprieve in New Analysis 1 comment

    • > What does Dark matter explain that MOND can't MOND describes, it doesn't explain. By adding a simple function to Newton's law of universal gravitation, it does a very good job of describing the momentum-deficit in the bulk motion of large optical and radio sources in a variety…

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  6. 'Dark fluid' with negative mass could dominate the universe 1 comment

    • > Dark matter can be placed arbitrarily Yes. > so it can match pretty much anything At the time you do the initial placement. But that's not the only relevant time. You can scatter any type of DM on a spacelike hypersurface any way you want, but then you have to figure out the…

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  7. Breakthrough Announced in Dark Matter Detection Technology 1 comment

    • > As a non-scientist Unfortunately you're missing the thrust of Hossenfelder's developing argument: in upgrading MOND to a full relativistic theory, you necessarily seriously blur the difference between "modified gravity" and "particle dark matter". There's some meat on this in…

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  8. Researchers find a galaxy without dark matter 1 comment

    • This is a couple of days old, and was discussed at length here: https://news.ycombinator.com/item?id=16701248 (~ 280 comments). Since then, however, McGauch (of modified gravity) put out a blog entry (dated yesterday)…

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  9. Supernova’s messy birth casts doubt on reliability of astronomical yardstick 1 comment

    • Second thing first: > ... much the same way physicists dislike the standard model in all of its' ugliness - even though it works Personally I think the U(1)xSU(2)xSU(3) group theory of the Standard Model of Particle Physics is quite pretty. AFAIK the problems with the Standard…

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  10. A Physicist Who Denies That Dark Matter Exists 2 comments

    • The problem is that your "lens" statement doesn't convey much information; if it goes deep, unfortunately it's not obvious. For example, it doesn't tell anyone whether you think that CDM is sparticles or a quantization of a function on the Ricci scalar or of a second metric or…

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    • > I've seen people create variants of MOND that try to address the Bullet Cluster problem, but you start having to have some sort of really weird gravity memory effect in space or something, where space itself "remembers" that it used to have a lot of matter in it and still has…

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