English

The $a_0$ -- cosmology connection in MOND

Astrophysics of Galaxies 2020-01-28 v1 General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

Abstract

I limelight and review a potentially crucial aspect of MOND: The near equality of the MOND acceleration constant, a0a_0 -- as deduced from local, galactic phenomena -- and cosmological parameters. To wit, a0cH0c2Λ1/2c2/Ua_0\sim c H_0\sim c^2\Lambda^{1/2}\sim c^2/\ell_U, where H0H_0 is the present value of the Hubble-Lema\^{i}tre constant, Λ\Lambda is the `cosmological constant', and U\ell_U is a cosmological characteristic length; e.g., the Hubble distance, or the de Sitter radius associated with Λ\Lambda. In itself, this near equality has some important phenomenological consequences, such as the impossibility of black holes, and of cosmological strong lensing, in the MOND regime. More importantly perhaps, this `coincidence' may be a pointer to the `FUNDAMOND' -- the more basic theory underlying MOND phenomenology. The manners in which such a relation emerges in existing, underlying scheme of MOND are also reviewed, interlaced with examples of similar relations in other physical systems, between apparently-fundamental velocity, length, and acceleration constants. Such analogies may point the way to explanation of the MOND `coincidence'.

Keywords

Cite

@article{arxiv.2001.09729,
  title  = {The $a_0$ -- cosmology connection in MOND},
  author = {Mordehai Milgrom},
  journal= {arXiv preprint arXiv:2001.09729},
  year   = {2020}
}

Comments

10 pages, 4 figures, Based on a talk at `BonnGravity2019 -- The functioning of galaxies: challenges for Newtonian and Milgromian dynamics', Bonn, September 2019

R2 v1 2026-06-23T13:21:31.702Z