Light coming from remote galaxies is redshifted and it is accepted that redshifts are produced by every galaxy running away from each other in a particular manner. According to this theory, galaxies can be grouped by the distance to earth in four spaces: the closer ones with no acceleration, the next ones with acceleration, the next remote ones with deceleration, and the farther ones without characterization. All that complexity is disregarded in this paper by assuming that the photons are ruled by longitudinal and transverse gravitational potentials. These relativistic invariant potentials create coherence quantum states of energy and subsequently the light redshift is created by photons moving down across those energetical levels.