An expanding universe without dark matter and dark energy

TL;DR

This paper proposes a new cosmological model that explains galaxy velocities, the horizon problem, and cosmic acceleration without dark matter or dark energy, by considering a different internal time measure for observers.

Contribution

It introduces a novel cosmological framework that accounts for key observations without dark components, challenging the standard Lambda-CDM paradigm.

Findings

Explains galaxy velocity dispersions without dark matter.

Solves the horizon problem without inflation.

Fits supernova observations without dark energy.

Abstract

Assuming that observers located inside the Universe measure a time flow which is different from the time appearing in the Friedmann-Lemaitre equation, and determining this time flow such that the Universe always appears flat to these observers, we derive a simple cosmological model which allows to explain the velocity dispersions of galaxies in galaxy clusters without introducing dark matter. It also solves the horizon problem without recourse to inflation. Moreover, it explains the present acceleration of the expansion without any resort to dark energy and provides a good fit to the observations of distant supernovae. Depending on the present value of the matter-energy density, we calculate an age of the Universe between 15.4 and 16.5 billion years, significantly larger than the 13.7 billion years of the standard Lambda-CDM model. Our model has a slower expansion rate in the early epochs, thus leaving more time for the formation of structures such as stars and galaxies.