A very interesting new result related to the problem of dark matter has emerged: see the ScienceDaily article In rotating galaxies, distribution of normal matter precisely determines gravitational acceleration. The original articl can be found at arXiv.org.
What is found that there is rather precise correlation between the gravitational acceleration produced by visible baryonic dark matter and and the observed acceleration usually though to be determined to a high degree by the presence of dark matter halo. According to the article, this correlation challenges the halo model model and might even kill it.
It turns out that the TGD based model in which galactic dark matter is at long cosmic strings having galaxies along it like pearls in necklace allows to interpret the finding and to deduce a formula for the density from the observed correlation.
 The model contains only single parameter, the rotation velocity of stars around cosmic string in absence of baryonic matter defining asymptotic velocity of distant stars, which can be determined from the experiments. TGD predicts string tension determining the velocity. Besides this there is the baryonic contribution to matter density, which can be derived from the empirical formula. In halo model this parameter is described by the parameters characterizing the density of dark halo.
 The gravitational potential of baryonic matter deduced from the empirical formula behaves logarithmically, which conforms with the hypothesis that baryonic matter is due to the decay of short cosmic string. Short cosmic strings be along long cosmic strings assignable to linear structures of galaxies like pearls in necklace.
 The critical acceleration appearing in the empirical fit as parameter corresponds to critical radius. The interpretation as the radius of the central bulge with size about 10^{4} ly in the case of Milky Way is suggestive.
 In Zero Energy Ontology (ZEO) TGD predicts a dimensional hierarchy of basic objects analogous to the brane hierarchy in Mtheory: spacetime surfaces as 4D objects, 3D lightlike orbits of partonic 2surfaces as boundaries of Minkowskian and Euclidian regions plus spacelike 3surfaces defining the ends of spacetime surface at the opposite boundaries of CD, 2D partonic surfaces and string world sheets, and 1D boundaries of string world sheets. The natural idea is to identify the dynamics Ddimensional objects in terms of action consisting of Ddimensional volume in induced metric and Ddimensional analog of Kähler action. The surfaces at the ends of spacetime should be freely choosable apart from the conditions related to to supersymplectic algebra realizing strong form of holography since they correspond to initial values.
For the lightlike orbits of partonic 2surfaces 3volume vanishes and one has only ChernSimons type topological term. For string world sheets one has area term and magnetic flux, which is topological term reducing to a mere boundary term so that minimal surface equations are obtained. For the dynamical boundaries of string world sheets one obtains 1D volume term as the length of string world line and the boundary term from string world sheet. This gives 1D equation of motion in U(1) force just like in Maxwell's theory but with induced Kähler form defining the U(1) gauge field identifiable as the counterpart of classical U(1) field of standard model. Induced spinor fields couple at boundaries only to induced em gauge potential since induced classical Wboson gauge fields vanish at string world sheets in order to achieve a welldefined and conserved spinorial em charge (here the absolutely minimal option would be that the W and Z gauge potentials vanish only at the timelike boundaries of string world sheet). Should worldline geometry couple to the induced em gauge field instead of induced Kähler form? The only logical option is however that geometry couples to the U(1) charge perhaps identifiable in terms of fermion number.
See the chapter TGD and Astrophysics or the article TGD interpretation for the new discovery about galactic dark matter.
