#### CarlB

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**Mach's Principle and a Variable Speed of Light**

Alexander Unzicker

Mach's principle, according to which the origin of gravitational interaction depends on the presence of all the masses in the universe, was expressed in a quantitative form by Sciama (1953). Since this idea suggests a variable speed of light (VSL), it is shown here that the arising variability of c is in agreement with all GR tests regarding time and length scales which are subject to variation as well. Moreover, VSL opens the possibility to write the total energy of a particle as [tex]E=mc^2[/tex]; 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 Newtons 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.

http://www.arxiv.org/abs/gr-qc/0511038

I just saw this on Arxiv and haven't read it yet. But I recognize the author as having written interesting papers before.

Carl