Dark Matter Not a Done Deal?
ScienceNow: Some arguments will never end. A year ago, astronomers reported observations that were widely hailed as proof positive for the existence of dark matter, the mysterious stuff whose gravity holds the galaxies together. But now a different team says that the very same observation can be explained by a controversial theory that rejects dark matter and alters the rules of gravity.
Comments
We follow with great interest the current debate on Dark Matter (DM). However, it is known already since Bergman (a student of Einstein) and Wagoner that scalar field model of DM coupled to standard general relativity is conformally equivalent to modified gravity. Thus axion type DM may simulated
MOND or vice versa. For more details see
Inflation, bifurcations of nonlinear curvature Lagrangians and dark energy
Authors: Eckehard W. Mielke, Fjodor V. Kusmartsev, Franz E. Schunck
(Submitted on 9 Apr 2007)
Abstract: A possible equivalence of scalar dark matter, the inflaton, and modified gravity is analyzed. After a conformal mapping, the dependence of the effective Lagrangian on the curvature is not only singular but also bifurcates into several almost Einsteinian spaces, distinguished only by a different effective gravitational strength and cosmological constant. A swallow tail catastrophe in the bifurcation set indicates the possibility for the coexistence of different Einsteinian domains in our Universe. This `triple unification' may shed new light on the nature and large scale distribution not only of dark matter but also on `dark energy', regarded as an effective cosmological constant, and inflation.
Comments: 20 pages, 8 figures, Proceedings of the 11th Marcel Grossmann Meeting (MG11) in Berlin, Germany, July 23-29, 2006
Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics (astro-ph)
Cite as: arXiv:0704.1135v1 [gr-qc]
Posted by: Eckehard W. Mielke | November 1, 2007 4:58 PM