The index of refraction of quasi-empty space

An early contention of A. Einstein regarding the influence of the magnetic field on the propagation of light is examined. It is found that the contention is compatible with the Cespedes-Cure hypothesis and the idea that the index of refraction of empty space containing magnetic energy density (Quasi–empty space) is modified by the total energy density of space mainly gravitational due to the far away stars and galaxies. Compelling evidence for the Cespedes-Cure hypothesis are coinciding values of the gravitational energy density of space * ρ due to the far-away stars and galaxies, calculated on application of the hypothesis to the Astronomical Lensing phenomenon and to the Pioneer Anomaly problem. Consequences include a revision of Doppler effect-derived radial velocities that lead to overestimation of recession velocities at locations with a decreased gravitational energy density. The radially decreasing mass density observed visually in galaxies may explain the “Flat rotation curve of galaxies” and an assumption of a finite universe with radially decreasing mass density leads to a plausible explanation of the deviation from linearity of Hubble’s law: the accelerated expansion of galaxies at extreme distances. Three possible earth bound laboratory experiments to provide additional evidence of the A. Einstein contention and the Cespedes-Cure hypothesis are presented.