MOND and TGD view of dark matter

The TGD based model explains the MOND (Modified Newton Dynamics) model of Milgrom for the dark matter. Instead of dark matter, the model assumes a modification of Newton's laws. The model is based on the observation that the transition to a constant velocity spectrum in the galactic halos seems to occur at a constant value of the stellar acceleration equal to a_cr =about 10^-11g, where g is the gravitational acceleration at the Earth. MOND theory assumes that Newtonian laws are modified below a_cr.

1. In TGD, dark energy plus magnetic energy would be associated with cosmic strings, which are "non-Einsteinian" 4-surfaces of M⁴× CP₂ with 2-D M⁴ projection. Cosmic strings are unstable agains thickening of the M⁴ projection so that one obtains Einsteinian monopole flux tube.

   In accordance with the observations of Zeldovich, galaxies would correspond to tangles along a long cosmic string at which the string has thickened and liberated its energy as ordinary matter (TGD counterpart for the decay of the inflaton field). The flux tubes create 1/ρ type gravitational field orthogonal to string and this gives rise to the observed flat velocity spectrum (see this, this, and this).

2. In MOND theory, it is assumed that gravitation starts to behave differently when it becomes very weak and predicts the critical acceleration. In the TGD framework, the critical acceleration would be of the same order of magnitude as the acceleration created by the gravitational field of the cosmic string and would also define a critical distance depending only on the string tension.
3. If 1/r² changes to 1/r in MOND, model one obtains the same predictions as in TGD for the planar orbits orthogonal to the long string along which galaxies correspond to a flux tube tangled. The models are not equivalent. In TGD, general orbit corresponds to a helical motion of the star along the cosmic string so that the concentration on a preferred plane is predicted. This has been recently reported as an anomaly of dark matter models (see this).
4. The critical acceleration predicted would correspond to acceleration of the same order of magnitude as the acceleration caused by cosmic string. From M²/R_cr= GM/R²_cr= TG/R_cr (assuming that dark matter dominates) one obtains the estimate R_cr=M/T and a_cr =GT²/M, where M is the visible mass of the object - for instance the ordinary matter of a galaxy. If critical acceleration is always the same, one would have T=(a_crM/G)^1/2 so that the visible mass would scale like M∝ T² if a_cr is constant of Nature.

See the chapter TGD and astrophysics.

For a summary of earlier postings see Latest progress in TGD.

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