MOUND: An Alternative to Milgrom’s MOND

Patrick G Tonin

doi:10.4236/ijaa.2021.111006

Abstract

We test and explore a Modified Universe Dynamics (MOUND) formula recently proposed by the author. We show that, similarly to Milgrom’s Modified Newtonian Dynamics (MOND), it is successful in accounting for the mass discrepancy in spiral galaxies, and it predicts the Baryonic Tully-Fisher Relation (BTFR) and the Radial Acceleration Relation (RAR). Contrary to Milgrom’s MOND, MOUND also explains the dynamics of galaxy clusters and does not rely on an empirical interpolating function or an ad hoc acceleration parameter.

Highlights

Modified Newtonian Dynamics (MOND) is a modification of Newtonian gravity first suggested by Milgrom [1] as an alternative to dark matter to account for the mass discrepancy in spiral galaxies
We test and explore a Modified Universe Dynamics (MOUND) formula recently proposed by the author
To Milgrom’s Modified Newtonian Dynamics (MOND), it is successful in accounting for the mass discrepancy in spiral galaxies, and it predicts the Baryonic Tully-Fisher Relation (BTFR) and the Radial Acceleration Relation (RAR)

Summary

Introduction

Modified Newtonian Dynamics (MOND) is a modification of Newtonian gravity first suggested by Milgrom [1] as an alternative to dark matter to account for the mass discrepancy in spiral galaxies. Notably successful in explaining rotation curves and kinematics of galaxies [1] [2], it falls short on galaxy clusters because additional undetected matter is still required [3] [4] [5]. In the MOUND approach, the Universe gravitational acceleration gu = 3.4365×10−10 m ⋅ s−2 couples with Newtonian acceleration, and Newtonian dynamics are preserved. The consequences of this coupling become apparent on large scales, when Newtonian acceleration is of the same magnitude as the Universe gravitational acceleration. We show that MOUND explains the dynamics of galaxies and those of galaxy groups and clusters. We demonstrate that it predicts the Radial Acceleration Relation (RAR) [9]

The MOUND Formula

Fits to Galaxies Curves

Galaxy Groups and Clusters

The Classic Newtonian formula

Conclusion