Two-way and One-way Vacuum Speed of Light under the Membrane Paradigm

The discovery of cosmic microwave background radiation (CMB) by Wilson and Penzias defines a rest frame in the sense of Newton’s absolute space. This fact is one of the reasons why brane worlds moved into the focus of interest. Membrane theory (CM) uses the cosmological model of a 4-dimensional thin membrane, expanding in hyperspace. A homogeneous vector field acts perpendicularly from outside onto the membrane and causes, this way, curvature of space and gravitation. The membrane defines an absolute Newtonian space, and forces small changes of Special Relativity (SR). The most important difference between CM and SR is the introduction of a cross contraction of moving bodies. Photons travel always and only in the rest inertial reference frame. There is no difference between two-way and one-way speed of light. Far away from masses photons move with constant speed c. The rest inertial reference frame is defined by the absence of the dipole of the cosmic microwave background radiation (CMB), caused by the Doppler-effect. The speed of light is anisotropic in each inertial reference frame that is in relative motion with respect to the rest frame. Although the speed of light is constant in the vacuum, it can be measured on Earth only with a systematic error of ± 36.9 m/s. The reason is that the flow of time of the clocks on the Earth is not constant. The measurement of the one-way speed of light is a special issue. Although the speed of light is anisotropic in each moving inertial reference frame, the time transformation hides this fact nearly perfectly. A co-moving observer registers the arrival of the light signal after a time interval which suggests that speed of light is always c. To obtain this result, it is sufficient to accept the existence of a rest inertial reference frame and the transformation of time given by FitzGerald and Lorentz