The major extant relativity theories-Galileos Relativity (GaR), Lorentzs Relativity (LR) and Einsteins Special Relativity (SR), with the latter much celebrated, while the LR is essentially ignored. Indeed it is often incorrectly claimed that SR and LR are experimentally indistinguishable. Here we show that (i) SR and LR are experimentally distinguishable, (ii) that comparison of gas-mode Michelson interferometer experiments with spacecraft earth-flyby Doppler shift data demonstrate that it is LR that is consistent with the data, while SR is in conflict with the data, (iii) SR is exactly derivable from GaR by means of a mere linear change of space and time coordinates that mixes the Galilean space and time coordinates. So it is GaR and SR that are equivalent. Hence the well known SR relativistic effects are purely coordinate effects and cannot correspond to the observed relativistic effects. The connections between these three relativity theories has become apparent following the discovery that space is an observable dynamical textured system and that space and time are distinct phenomena, leading to a neo-Lorentz Relativity (nLR). The observed relativistic effects are dynamical consequences of nLR and 3-space. In particular a proper derivation of the Dirac equation from nLR is given, which entails the derivation of the rest mass energy mc2.
