Reflection of light as a mechanical phenomenon applied to the Michelson interferometer with sunlight as a source

Emission, propagation, and reflection of light are mechanical phenomena; therefore, these phenomena are observed in an inertial frame as in the frame at absolute rest. At Cleveland Laboratory in 1924, Miller performed experiments with a Michelson interferometer employing local sources and sunlight. The fringe shift is zero in experiments such as the Michelson‐Morley, where the source and mirrors are at rest in Earth's inertial frame, which explains Miller's experiments with local sources. When the source or/and mirrors are in motion in an inertial frame, there is a fringe shift. The Sun is an inertial frame at relative rest in which its light travels at the speed c in any direction, and Earth travels at the orbital speed v . This is the case of Miller's experiments with sunlight for which this article predicts an unobservable fringe shift in the range of 10 − 8 . Thus, the Cleveland Laboratory experiments involving sunlight and local sources are explained. Miller's observed fringe shift of 0.08 in 1921 and 0.088 in 1925 at Mount Wilson remains unclear, leaving this subject open to theoretical and experimental challenges.