Varying-G Cosmology with Type Ia Supernovae

TL;DR

This paper investigates whether variations in gravitational strength over cosmic time can explain Type Ia supernovae observations, offering an alternative to dark energy hypotheses and accessible for undergraduate research.

Contribution

It proposes a varying-G cosmological model as an alternative explanation for supernova data, expanding the scope of possible cosmological theories.

Findings

Varying-G models can fit supernova data without dark energy.

The approach is suitable for undergraduate research and education.

Provides a conceptual framework for alternative cosmological explanations.

Abstract

The observation that Type Ia supernovae are fainter than expected given their red shifts has led to the conclusion that the expansion of the universe is accelerating. The widely accepted hypothesis is that this acceleration is caused by a cosmological constant or, more generally, some dark energy field that pervades the universe. This hypothesis presents a challenge to physics so severe that one is motivated to explore alternative explanations. In this paper, we explore whether the data from Type Ia supernovae can be explained with an idea that is almost as old as that of the cosmological constant, namely, that the strength of gravity varies on a cosmic timescale. This topic is an ideal one for investigation by an undergraduate physics major because the entire chain of reasoning from models to data analysis is well within the mathematical and conceptual sophistication of a motivated undergraduate.