Observationally Verifiable Predictions of Modified Gravity

TL;DR

MOG is a relativistic modified gravity theory that explains astronomical phenomena without dark matter, matching observations of galaxy dynamics, lensing, and cosmology, and predicts testable deviations from Einstein's theory.

Contribution

This paper introduces exact and approximate solutions to MOG's field equations, demonstrating its consistency with various astrophysical observations and its potential to replace dark matter in cosmology.

Findings

MOG reproduces galaxy rotation curves and cluster masses without dark matter.

MOG predicts an accelerating universe consistent with observations.

Future experiments could distinguish MOG from standard cosmology.

Abstract

MOG is a fully relativistic modified theory of gravity based on an action principle. The MOG field equations are exactly solvable numerically in two important cases. In the spherically symmetric, static case of a gravitating mass, the equations also admit an approximate solution that closely resembles the Reissner-Nordstrom metric. Furthermore, for weak gravitational fields, a Yukawa-type modification to the Newtonian acceleration law can be obtained, which can be used to model a range of astronomical observations. Without nonbaryonic dark matter, MOG provides good agreement with the data for galaxy rotation curves, galaxy cluster masses, and gravitational lensing, while predicting no appreciable deviation from Einstein's predictions on the scale of the solar system. Another solution of the field equations is obtained for the case of a a spatially homogeneous, isotropic cosmology. MOG predicts an accelerating universe without introducing Einstein's cosmological constant; it also predicts a CMB acoustic power spectrum and a mass power spectrum that are consistent with observations without relying on non-baryonic dark matter. Increased sensitivity in future observations or space-based experiments may be sufficient to distinguish MOG from other theories, notably the LCDM "standard model" of cosmology.