Results of a one-way experiment to test the isotropy of the speed of light

TL;DR

This experiment tests the isotropy of the speed of light using an improved Fizeau setup, finding no significant diurnal variation and supporting the invariance of light speed as postulated by Special Relativity.

Contribution

The paper introduces an improved experimental method to test light speed isotropy, achieving higher precision and confirming Einstein's postulate with a tighter limit on possible variations.

Findings

No significant diurnal variation detected

Established a limit of about 1/50 of previous experiments

Results support the invariance of the speed of light

Abstract

This paper presents the outcome of an experiment based on an improved version of Fizeau's coupled-slotted-discs that tests the fundamental postulates of Special Relativity for the one-way speed of light propagation. According to our methodology, important phenomena - a limit on and the diurnal regularity of the variation of the speed of light due to the movements of the Earth (assuming that the speed of light follows a Galilean transformation) - can be tested by the present experiment. However, these measurements do not indicate any significant diurnal variation. Consequently, the limit of the present outcome on the variation of the speed of light is insignificant. Assuming that the speed of light is not invariant and performing a rigorous statistical analysis, the limit established is approximately 1/50 of the previous Fizeau-type experiment with 95% confidence level. These outcomes are consistent with the assumptions of Einstein's Special Relativity.