The Real Problem with MOND

TL;DR

This paper critically examines the limitations of MOND, a modified gravity model, in explaining cosmic phenomena traditionally attributed to dark matter, highlighting the most significant unresolved challenge.

Contribution

It identifies and discusses the most severe unresolved challenge facing MOND, emphasizing the need for further investigation into its viability.

Findings

MOND fits galaxy rotation curves well

MOND predicts baryonic mass-velocity relation

MOND faces significant unresolved challenge

Abstract

Gravitational potentials in the cosmos are deeper than expected from observed visible objects, a phenomenon usually attributed to dark matter, presumably in the form of a new fundamental particle. Until such a particle is observed, the jury remains out on dark matter, and modified gravity models must be considered. The class of models reducing to MOdified Newtonian Dynamics (MOND) in the weak field limit does an excellent job fitting the rotation curves of galaxies, predicting the relation between baryonic mass and velocity in gas-dominated galaxies, and explaining the properties of the local group. Several of the initial challenges facing MOND have been overcome, while others remain. Here I point out the most severe challenge facing MOND.