The purpose of this paper is to show that the main principles on which physics has been based can be regarded as possible consequences of a unique axiom. This idea leads to a Space-Time Quantum Mechanics which obeys the same principles as does ?The hypothesis of the Quantum Space-Time Aether?. This hypothesis is based on the unification of the physical meaning of notions which derive from either General Relativity Theory or Quantum Mechanics.
The paper critically examines the experiments checking the Doppler effect formula in the form . A series of measurements was performed using accelerators imparting energies of up to 2,000 keV to hydrogen ions and observing the spectral Doppler shift at angles of 77o and 257o from the direction of motion. Special attention was paid to the effect of the hydrogen pressure and other influences that may not have been fully appreciated in previous experiments. The results demonstrate that the classical formula for the Doppler effect  is valid. But it is shown that a rigorous relativistic analysis yields the same result.