MOND laws of galactic dynamics

TL;DR

This paper demonstrates how MOND's core principles lead to specific galactic laws that are independent of complex histories, contrasting with dark matter models which do not predict such clear-cut laws.

Contribution

It shows that MOND laws naturally follow from its basic tenets, providing a unified explanation for galactic dynamics without relying on detailed histories.

Findings

MOND laws are derived from basic premises of the paradigm.

These laws are predicted to hold across all MOND theories.

Contrasts with dark matter models which lack such clear laws.

Abstract

MOND predicts a number of laws that galactic systems should obey irrespective of their complicated, haphazard, and mostly unknowable histories -- as Kepler's laws are obeyed by planetary systems. The main purpose of this work is to show how, and to what extent, these MOND laws follow from only the paradigm's basic tenets: departure from standard dynamics at accelerations a<~a0, and space-time scale invariance in the limit a<<a0. Such predictions will be shared by all MOND theories that embody these premises. This is important because we do not know which of the existing MOND theories, if any, is a step in the right direction. In the Newtonian-dynamics-plus-dark-matter paradigm, the validity of such clear-cut laws -- which tightly constrain baryons, `dark matter', and their mutual relations -- is contrary to expectations.