Emission, propagation, and reflection of light as mechanical phenomena in inertial frames are based on the behavior of balls at the limit when their mass is zero. The kinematics of massless balls is like that of balls with mass. Light as a wave or particle is a massless entity. Therefore, it is natural to apply the kinematics of the massless balls to light. Consequently, the kinematics of light depends on its kinetics of electromagnetic nature and its kinematics of mechanical nature in its interactions of emission and reflection with the matter. The study of the physics phenomena in the frame at absolute rest includes those in the inertial frames. Considering this and applying the emission, propagation, and reflection of light as mechanical phenomena in the vacuum of the frame at absolute rest, this study derives formulas for the speed of the wavefront of a ray of light reflected by a fixed and moving mirror when the light comes from a fixed and moving source. The derived formulas apply to the modified Michelson interferometer, employed independently by R. Tomaschek and D. C. Miller in their experiments.

Derivation of light paths in the Michelson interferometer is based on the hypothesis that the speed of light does not change after reflection by a mirror in motion. The Michelson-Morley experiment predicts a fringe shift of 0.40. The same fringe shift is predicted for a particular Michelson interferometer in which the beam splitter of the interferometer makes an angle of 45° with the direction of light from the source. Light behaves like a wave and also as a particle. Thus, it is reasonable to consider the reflection of light as a mechanical phenomenon. With this hypothesis, the speed of light changes after reflection, and the predicted fringe shift for the particular Michelson interferometer is zero which is in accordance with the result of the Michelson-Morley experiment. Apparently, light travels in any inertial frame as if this particular interferometer belongs to a fixed frame. The velocity of light is considered independent of the velocity of its source, which is in accordance with astronomers’ observations of the binary stars, and the experiment performed at CERN, Geneva, in 1964.

The Sun is a frame at relative rest in which sunlight travels at the emitted speed c. Earth travels at the revolving speed v in this frame. The reflection of light as a mechanical phenomenon applies to the modified Michelson interferometer employed by Miller in his experiments with light from the Sun. Unlike the Tomaschek experiments, which use light from stars that may travel in the Universe at velocities different from that of the Sun, the fringe shifts in the Miller experiments are predictable. Based on Michelson's derivation, Miller expected in his experiments at Mount Wilson a 1.12 fringe shift and observed a fringe shift of 0.08 in 1921 and 0.088 in 1925. The reflection of light as a mechanical phenomenon predicts zero fringe shift for Miller's experiment agreeing only with his observations at the Cleveland laboratory in 1924.

Light travels in a moving medium through densities that differ from the density of that medium at rest. This study derives a formula for light velocity through a moving medium for any direction of light propagation in that medium that, applied to the Fizeau experiment, gives a fringe shift of 0.23541. The Fresnel drag coefficient applied to the Fizeau experiment offers a fringe shift of 0.20466. The mean of the fringe shift observations in the Fizeau experiment of 0.23016 confirms both expectations.

The study of the emission, propagation, and reflection of balls in Newtonian mechanics, applying the laws of conservation of momentum and energy when the mass of the balls converges to zero, concludes that the kinematics of light are like those of massless balls. The kinematics of light explain why the speed of light is the constant c in each inertial frame in which the light source and reflective mirror are at rest, why the laws of physics have the same form in each inertial frame, and why any light experiment in an inertial frame cannot prove the motion of that inertial frame. The following law of mechanics governs the kinematics of balls and electromagnetic radiation: Each inertial frame drags at its velocity the balls and electromagnetic radiation emitted by bodies at rest in that inertial frame. The theory of special relativity misapplies the symmetry observed in phenomena to two inertial frames; therefore, it duplicates a physical phenomenon from one inertial frame, which is considered stationary, into another. There are multiple issues rooted in Lorentz's and Einstein's transformations. For example, transformations offer the speed of light at the constant c in the moving and opposite directions of the inertial frame. At the same time, it is variable in any other direction, converging to infinity. Time contraction in the moving direction of the inertial frame is different from time dilation in the opposite direction. It requires a ruler and time synchronization in each direction. There are no length contractions in Lorentz's and Einstein's transformations to support the fundamental concept of length contraction in special relativity. With these unacceptable conclusions, the theory of special relativity is self-negating.