Modified gravity as a common cause for cosmic acceleration and flat galaxy rotation curves

TL;DR

This paper proposes a modified gravity theory that explains both flat galaxy rotation curves and cosmic acceleration without invoking dark matter or dark energy, suggesting a common underlying cause.

Contribution

It introduces a unified modified gravity framework that accounts for galactic and cosmic phenomena traditionally attributed to dark matter and dark energy.

Findings

Flat galaxy rotation curves explained without dark matter

Cosmic acceleration explained without dark energy

Unified gravity theory applies across different scales

Abstract

Flat galaxy rotation curves and the accelerating Universe both imply the existence of a critical acceleration, which is of the same order of magnitude in both the cases, in spite of the galactic and cosmic length scales being vastly different. Yet, it is customary to explain galactic acceleration by invoking gravitationally bound dark matter, and cosmic acceleration by invoking a `repulsive` dark energy. Instead, might it not be the case that the flatness of rotation curves and the acceleration of the Universe have a common cause? In this essay we propose a modified theory of gravity. By applying the theory on galactic scales we demonstrate flat rotation curves without dark matter, and by applying it on cosmological scales we demonstrate cosmic acceleration without dark energy.