Mach's Principle and a Variable Speed of Light

TL;DR

This paper explores a variable speed of light theory inspired by Mach's principle, linking it to gravity, cosmology, and the equivalence principle, and demonstrating its consistency with classical tests of relativity.

Contribution

It introduces a variable speed of light model based on Mach's principle that aligns with classical tests and offers alternative explanations for cosmological issues.

Findings

VSL model reproduces classical tests of general relativity

Proposes a formula for c depending on mass distribution

Suggests an alternative to the flatness and horizon problems

Abstract

Ernst Mach (1838-1916) suggested that the origin of gravitational interaction could depend on the presence of all masses in the universe. A corresponding hypothesis of Sciama (1953) on the gravitational constant, c^2/G = \sum m_i/r_i, is linked to Dicke's (1957) proposal of an electromagnetic origin of gravitation, a precursor of scalar-tensor-theories. In this an equivalent description in terms of a variable speed of light (VSL) is given, and the agreement with the four classical tests of general relativity is shown. Moreover, VSL opens the possibility to write the total energy of a particle as E=mc^2; this necessarily leads to the proportionality of inertial and gravitating mass, the equivalence principle. Furthermore, a formula for c depending on the mass distribution is given that reproduces Newton's law of gravitation. This mass distribution allows to calculate a slightly variable term that corresponds to the `constant' G. The present proposal may also supply an alternative explanation to the flatness problem and the horizon problem in cosmology.