ABSTRACT
It is shown that the total escape speed u (i.e. from all the masses in space), which depends on the total gravitational potential U through the relation u = (−2U)1/2, tends to c; then, under the 1st condition c = u, and assuming (as a 2nd condition) the light as composed of longitudinally-extended, elastic (i.e. variable length) and massive particles, (photons), emitted at speed u referred to the initial location (O) of their source, we show that c referred to O becomes invariant despite any motion of its source from O. We revised the Doppler effect for the light, the gravitational redshift cause, the time dilation, highlighting the differences with respect to the Relativity. In the 2nd part, considering (3rd condition) the electron charge as a point-particle fixed to the electron surface and facing the atom nucleus during the electron orbit, the light-matter interaction becomes a consequence of the particular impacts between these photons and the circling electrons: e.g., on H atom, we found 137 circular orbits only, the last one being the ionization orbit, where the electron orbital speed becomes v i= c/1372. [Classical physics, under the assumption that a circling electron should produce (like a macroscopic electric circuit), an electro-magnetic radiation, implies that this claimed effect has to cause the electron fall into its nucleus: on Section 2.5, we show that the e.m. radiation of a circling electron only happens between two circular orbits].