"... get into specific details." From McGaugh's MOND PAGES, "When we measure the amount of luminous mass (stars and gas) in these systems and apply Newton's Law of Gravity, the observed mass falls well short of the amount required to explain the observed orbital speeds. This is the mass discrepancy. There are two logical possibilities to explain the observed mass discrepancies:

Either Most of the Mass in the Universe is Invisible (Dark Matter), or Dynamical Laws must be Modified (MOND).

There are significant challenges to both ideas. Issues for MOND:

Can a modified force law explain all observations?

Can a satisfactory theory encompassing both General Relativity and MOND be found?

Issues for Dark Matter:

Does the stuff we call Dark Matter really exist?

Can a dark matter based theory explain the MONDian phenomenology observed in rotation curves?

Why should the mass discrepancy only appear at a particular acceleration scale?"

It appears to me that there are 2 basic alternatives: (1) Newtonian-Einsteinian gravitational theory is 100% correct but appears to wrong for some unknown reason (weird quantum effect based upon the string landscape?) OR (2) Newtonian-Einsteinian gravitational theory really is significantly wrong. For the 1st alternative I posted some dubious speculations at NKS Forum Applied NKS. What if the 2nd alternative is true?

What is the simplest interpretation of Milgrom's MOND? The answer might be that the law of conservation of gravitational energy is false. Consider Einstein's "The Meaning of Relativity", 5th edition, page 84. Concerning the fundamental geometric tensor, Einstein wrote "3. Its divergence must vanish identically. ... it may be proved that this third condition requires a to have the value -1/2." I say that Milgrom is the Kepler of contemporary cosmology and that the constant a should be -1/2 dark-matter-compensation-constant, where this dark-matter-compensation-constant is some very small positive number to be determined by experiment. I claim that an easy scaling argument shows that this idea is approximately equivalent to MOND. I suggest that the Gravity Probe B science team misinterpreted their own data, and that a good value for the hypothetical dark-matter-compensation-constant can be found by analyzing the Gravity Probe B data under the assumption that the 4 ultra-precise gyroscopes functioned to within design specifications. The reanalysis should decisively disconfirm or confirm my simplistic idea. My idea is that Einstein's equivalence principle is 100% true for mass-energy that is implicitly or explicitly measured and 100% false for virtual mass-energy. My guess is that dark matter is virtual mass-energy that has positive gravitational mass-energy and ZERO inertial mass-energy while dark energy is virtual mass-energy that has negative gravitational mass-energy and ZERO inertial mass-energy. By assuming that nature is finite and digital and that string vibrations are confined to 3 copies of the Leech lattice, it might be possible to justify the preceding speculative idea.

6 days later

  • [deleted]

  • Post #8

David,

I enjoyed your article, and especially some of your quotes. I believe good quotes are particularly relevant for essays. Particularly Witten's observation that "there is not yet any proof that the theory is relevant to physics." In my current essay I refer to this as a map that does not point to any territory. Also liked Gross's remark that "String theory is part and parcel of quantum field theory."

By the way, based on remarks of his that I've read, I'm amazed that Witten responded to you. Congratulations!

Of your three basic alternatives I would favor the second, that Newtonian-Einstein gravitational theory is correct but appears wrong because of neglect of non-linear mechanisms. The flat rotation curves are real, but MOND appears to be a 'patch' to explain them. That's just my opinion. Your suggestion that string theory could solve the problem is interesting.

Like Philip, I too like your (first) quote from Crick. My essay treats a specific case in point. I invite you to read my essay and leave an opinion.

Best regards,

Edwin Eugene Klingman

    Edwin: Thank you for you congratulatory sentiment. Is MOND more than a 'patch'? Is the MOND acceleration constant actually an important constant of nature -- even if such a constant is not precisely defined to more than 20% ? In connection with the "dark-matter-compensation-constant" there are the questions: (1) Is such a constant consistent with the empirical facts? (2) If such a constant is consistent with the empirical facts, then what does the constant really mean in terms of the foundations of physics? Is Milgrom the Kepler of contemporary cosmology? Those researchers who are interested in the preceding question should consider a further question: Should physicists consider the problem of attempting to prove, under plausible physical hypotheses, that the Anderson-Campbell-Ekelund-Ellis-Jordan flyby anomaly formula is approximately equivalent to replacing the -1/2 in the standard form of Einstein's field equations by -1/2 dark-matter-compensation-constant ?

    "Anomalous Orbital-Energy Changes Observed during Spacecraft Flybys of Earth" by Anderson et al., PhysRevLett, 2008

    Regards, David Brown

    4 days later

    Another model for the unification of quantum field theory and general relativity theory is Scalar Theory of Everything model correspondence to the Big Bang model and to Quantum Mechanics .

    Spiral galaxy rotations curves also have an asymmetry that other models do not attempt to explain. Because ``accepted'' physics has tried and failed (including MOND) to explain the asymmetric rotation curves, these seem ripe for a forum like FQXi. My model is Scalar potential model of spiral galaxy HI rotation curves and rotation curve asymmetry .

    Dear Mr. Fisher: The idea that "... reality must already be fully unified in order for it to be realistic ..." might be true in that nature's reality has no need of validation by mathematical theories. According to L. E. J. Brouwer, "Mathematics is nothing more, nothing less, than the exact part of our thinking." Reality is what it is, no matter what I think. My conjecture, what I call the Milgrom Denial Hypothesis, i.e. the main problem with string theory is that string theorists fail to realize that Milgrom is the Kepler of contemporary cosmology, involves the assumption that Milgrom, McGaugh, Kroupa, and Pawlowski are empirically correct and the assumption that string theory, in some form, can explain dark matter. I am not entirely sure that string theory can explain dark matter. According to Edward Witten, "... string theory has proved to be remarkably rich, more so than even the enthusiasts tend to realize. It has led to penetrating insights on topics from quark confinement to quantum mechanics of black holes, to numerous problems in pure geometry. All this suggests that string theory is on the right track; otherwise, why would it generate so many unexpected ideas? And where critics have had good ideas, they have tended to be absorbed as part of string theory, whether it was black hole entropy, the holographic principle of quantum gravity, noncommutative geometry, or twistor theory."

    "Unravelling string theory" by Edward Witten, Nature, vol. 438, 22/29 December 2005

    From an operational viewpoint, I say that string theorists must somehow incorporate Milgrom's MOND into string theory -- the empirical evidence suggests this.

    David,

    Very provocative in posing the questions. Also good reference articles and abstracts listing for the inquiring minds. Mond is an 'outsiders' pursuit, but does ask us to discover a correct question. I have amused myself from time to time with the notion that in the future all those solutions^500 might be seen as a naively obtained inventory of radial fluctuations of energy seeking equilibrium as an ideal spherical rest mass. Good luck, for what its worth my rating is as an amateur. jrc

    Dear Mr. Brown,

    There is a simple explanation for "dark matter" Real matter is not shaded. Although real matter appears to us to consist of solid, liquid and gaseous elements that is because as far as we can tell, we are constituted of solid, liquid and gaseous content. If that is true, then all reality must consist of real solid, liquid and gaseous incorporation. Real empty space cannot exist. Only matter exists.

    Regards,

    Joe Fisher

    David,

    A pretty good read with lots of thoughtful questions. The answers can only be had through experiment and observation as you note in some of the comments.

    Best Regards,

    Gary Simpson

      Gary,

      Thank you for your comments on my essay. In your essay "Calculus - Revision 2.0" page 7, you wrote, "It is only through the comparison between prediction and experiment that we can hope to understand." Physics without prediction is unsatisfactory. String theorists need to find a way to eliminate, or at least drastically constrain, the string landscape. My guess is that Milgrom's MOND is the key to eliminating the string landscape and to making decisive, testable predictions with string theory. String theorists need to incorporate MOND into string theory. Consider the problem of attempting to prove, under plausible physical hypotheses, that the Anderson-Campbell-Ekelund-Ellis-Jordan flyby anomaly formula is approximately equivalent to replacing the -1/2 in the standard form of Einstein's field equations by -1/2 dark-matter-compensation-constant.

      "Anomalous Orbital-Energy Changes Observed during Spacecraft Flybys of Earth" by Anderson et al., PhysRevLett, 2008

      Anyone interested in the foundations of physics might find to worthwhile to consider the preceding problem.

      -- David Brown

      string theory has no bijective epistemological correspondence with physical world. It is a pure fantasy.

        Amrit Sorli (Foundations Of Physics Institute): In your essay "Application of Bijective Function of Set Theory in Physics" you wrote, "Mathematics is the useful tool of physics. However out of pure mathematical laws we cannot deduce physical laws." The logical possibilities seem to be vastly greater than the physical possibilities. My guess is that vibrating strings at or below the Planck scale are a reality, in some sense. According to Burton Richter, "... Progress in physics almost always is made by simplification. ... To the Landscape Gardeners I would say calculate the probabilities of alternative universes, and if ours does not come out with a large probability while all others with content far from ours come out with negligible probability, you have no useful contribution to make to physics. ..."

        Is "Naturalness" Unnatural? Presentation at SUSY '06, Prof. Burton Richter, Stanford University, 14 June 2006

        I maintain the Milgrom Denial Hypothesis: The main problem with string theory is that string theorists fail to realize that Milgrom is the Kepler of contemporary cosmology. Why do I maintain this hypothesis? String theory seems to be the mathematics of quantum gravity, while Milgrom, McGaugh, Kroupa, Pawlowski, and others have empirical evidence that gravity is Milgromian, whatever that might turn to be in terms of string theory. If string theory is merely a mathematical fantasy it has certainly been a productive fantasy for mathematics. The mathematical unification of quantum field theory and general relativity theory might, by logical necessity, be some form of string theory or M-theory.

        11 days later

        Dear David,

        I just read your essay and the refreshing ideas proposed. Your essay should score highly even though to your question: Does dark matter exist? My answer is Yes, it does and not only that it exists right there inside your office and laboratory. If you are inclined to discuss the proof, we can take this further.

        Best regards,

        Akinbo

        Please note: I share your skepticism about string theory.

          Dear Akinbo,

          In your essay "Does the division of extension mean the same in mathematics as it does in physics?" (page 5), there is the statement: "It appears that without the addition of some further ingredient into our physics, there are subtle nuances to what we call discrete and how it can be fundamentally expressed." I guess that, more specifically, one or more new physical hypotheses need to be introduced into string theory in order to explain dark matter and the space roar. My quantum theory of gravity has several basic assumptions: Dark matter is virtual mass-energy that has positive gravitational mass-energy and zero inertial mass-energy. Dark energy is virtual mass-energy that has negative gravitational mass-energy and zero inertial mass-energy. Nature is finite and digital, more-or-less as described in Wolfram's "A New Kind of Science", Chapter 9. The Koide formula, Lestone's heuristic, and 't Hooft's superstring determinism are necessary for understanding the foundations of physics. The Fernández-Rañada-Milgrom Effect, the Space Roar Profile Prediction, and the 64 Particles Hypothesis are empirically valid. According to the Gravity Probe B science team, my quantum theory of gravity has already been refuted. (I dispute the Gravity Probe B science team's interpretation of their own experiment.) In any case, I affirm the Milgrom Denial Hypothesis: The main problem with string theory is that string theorists fail to realize that Milgrom is the Kepler of contemporary cosmology. Why do I affirm this? The mathematic evidence supports string theory, and the empirical evidence supports Milgrom's acceleration law (according to the work of Milgrom, McGaugh, Kroupa, and Pawlowski).

          -- D. Brown

          Dear David Brown,

          I am so somewhat surprised that you link the question of dark matter with string theory so strongly. MOND was proposed as a way to account for the flat rotation curves of stars in galaxies, and is not committed to any particular account of the nature or origin of the dark matter. And cosmological observations of gravitational lensing effects have become much more exact and sophisticated since 1983. The Bullet Cluster has been cited as fairly direct evidence for dark matter. Do you have results that show how to account for these observations without dark matter, and just with a modification of the gravitational dynamics?

          Regards,

          Tim Maudlin

            Sorry: I meant that the dark matter explanation of the rotation, as opposed to MOND, is not committed to any particular account of the dark matter, and in particular not to string theory.

            Dear Tim Maudlin,

            In your essay "How Mathematics Meets the World" there is the statement, "The puzzle is why the language of mathematics should be such an effective tool for describing the physical world." My guess is that the solution to the puzzle is: Nature is finite and digital with string vibrations confined to 3 copies of the Leech lattice. Why is string theory likely to be 'the only game in town'? Google "mystery magic matrix witten". What is the empirical evidence for MOND? Google "kroupa pawlowski milgrom new paradigm". Does the Bullet Cluster show that dark matter particles exist? See:

            Milgrom's perspective on the Bullet Cluster, The MOND Pages

            What is the empirical evidence for the Fernández-Rañada-Milgrom effect? See:

            Does the Rañada-Milgrom Effect Explain the Flyby Anomaly?

            My thinking is that the empirical evidence favors MOND, the mathematical evidence favors string theory (or M-theory), and the Fernández-Rañada-Milgrom effect is likely to be the string theoretical interpretation of MOND. I claim that an easy scaling argument demonstrates that the alleged effect is approximately equivalent to MOND. If in the standard form of Einstein's field equations the -1/2 is replaced by -1/2 + dark-matter-compensation-constant, gravitational lensing works approximately as well merely because the dark-matter-compensation-constant is very small in comparison to 1/2.

            4 days later

            Dear Sir,

            We have discussed relativity critically in our essay. Since GR is also an inverse square theory, if MOND is correct, GR would also need modification. But for this modified versions to work, some sort of unseen or "dark" presence is a must, which looks a lot like dark matter. It won't be described by particles in the way that dark matter is described - it may be described in a more wavelike form or a more field-like form. In other words, MOND can do away with dark matter but cannot describe the universe simply as the product of a tweaked Einsteinian gravity acting on the mass we can see. It modifies gravity, but through the backdoor it introduces extra fields, which mean that the distinction between dark matter and modified gravity isn't very clear. In a paper "No Evidence for a Dark Matter Disk within 4 kpc From the Galactic Plane" (http://arxiv.org/abs/1011.1289) the authors note that their findings directly contradict the predictions of MOND.

            The energy "uncertainty" introduced in quantum theory combines with the mass-energy equivalence of special relativity to allow the creation of particle/anti-particle pairs by quantum fluctuations when the theories are merged. As a result there is no self-consistent theory which generalizes the simple, one-particle Schrödinger equation into a relativistic quantum wave equation. QED began not with a single relativistic particle, but with a relativistic classical field theory, such as Maxwell's theory of electromagnetism. This classical field theory was then "quantized" in the usual way and the resulting quantum field theory is claimed to be a combination of quantum mechanics and relativity. However, this theory is inherently a many-body theory with the quanta of the normal modes of the classical field having all the properties of physical particles. The resulting many-particle theory can be relatively easily handled if the particles are heavy on the energy scale of interest or if the underlying field theory is essentially linear. Such is the case for atomic physics where the electron-volt energy scale for atomic binding is about a million times smaller than the energy required to create an electron positron pair and where the Maxwell theory of the photon field is essentially linear.

            However, the situation is completely reversed for the theory of the quarks and gluons. While the natural energy scale of these particles, the proton, meson, etc. is on the order of hundreds of millions of electron volts, the quark masses are about one hundred times smaller. Likewise, the gluons are said to be quanta of a Yang-Mills field which obeys highly non-linear field equations. As a result, strong interaction physics has no known analytical approach and numerical methods are said to be the only possibility for making predictions from first principles and developing a fundamental understanding of the theory. In QCD, the non-linearities in the theory have dramatic physical effects. One coherent, non-linear effect of the gluons is to "confine" both the quarks and gluons so that none of these particles can be found directly as excitations of the vacuum. Likewise, a continuous "chiral symmetry", normally exhibited by a theory of light quarks, is broken by the condensation of chirally oriented quark/anti-quark pairs in the vacuum. The resulting physics of QCD is thus entirely different from what one would expect from the underlying theory, with the interaction effects having a dominant influence.

            There is an urgent need to rewrite physics.

            Regards,

            basudeba

              Dear Miss. Sujatha Jagannathan:

              In your essay "Trick or Truth: The Mysterious Connection Between Physics and Mathematics", you state: "The puranic view asserts that the universe is created, destroyed, and re-created in an eternally repetitive series of cycles." My theory assumes that the preceding idea is basically correct but my theory is based upon Wolfram's atheistic, materialistic theory as expounded in "A New Kind of Science" (see NKS Forum, Applied NKS). However, according to the Space Probe B science team, my theory has already been ruled out. (If the 4 ultra-precise gyroscopes malfunctioned in the manner suggested by the Space Probe B science team, then I agree that my theory is wrong.) In any case, I think that Milgrom is the Kepler of contemporary cosmology (on the basis of empirical evidence accumulated by Milgrom, McGaugh, Kroupa, Pawlowski, and others). What MOND really means is unclear even to Milgrom.

              -- D. Brown

              Dear Basudeba Mishra,

              In your essay "Reasonable Effectiveness of Mathematics", you state "The validity of a physical statement is judged by its correspondence to reality." Judging whether a physical theory corresponds to empirical reality depends upon the fairness of the empirical tests. I claim that the string theorists fail to realize that the empirical game is rigged against MOND (by vested interests in dark matter particles). According to Milgrom, "The MOND Paradigm", 2008, page 7 (http://arxiv.org/abs/0801.3133) "Disc galaxies are predicted to exhibit a disc mass discrepancy, as well as the spheroidal one that is found for any mass. In other words, when MOND is interpreted as DM we should deduce a disc component of DM as well as a spheroidal one ..." The publication "No evidence for a dark matter disk within 4 kpc of the galactic plane" by C. Moni Bidin, G. Carraro, A. Méndez, and W. F. van AltenaI puts forward a model based upon 6 assumptions (pages 5 & 6): "I Steady state. The thick disk is in equilibrium with the Galactic potential, as expected for anold stellar population. Therefore, all temporal derivatives are set to zero. II Locally flat rotation curve. The rotation curve is assumed flat at the solar Galactocentricdistance. III No net radial or vertical stellar flux. The mean radial and vertical velocity components are zero, while the rotational component shows a non-null lag ... IV Exponential radial dispersion profiles. ... V Vertical constancy of scale lengths. ..." The assumption of a locally flat rotation curve needs to be explained by DM, MOND, or some other (as yet) unverified theory because Newton-Einstein gravitational theory does not predict a locally flat rotation curve. To interpret MOND as dark matter particles that obey the equivalence principle either does not work or requires some drastic new hypothesis, so that "a disc component of DM" does not really mean in MOND what "a disc component of DM" means in cold dark matter theory. There is a pressing need for a relativistically precise version of MOND (WHICH MATCHES THE EMPIRICAL EVIDENCE). I conjecture that anyone who wants to fully understand MOND needs to explain the space roar and the photon underproduction crisis.

              -- D. Brown