Within the framework of the Theory of Time Frames, we have revealed an intuitive explanation for the longstanding enigma surrounding the constancy of light speed in a vacuum. This was achieved through the astonishingly straightforward logic that acknowledges a photon's speed varies in proportion to the flow of time and the established fact that photons do not possess rest mass. Consequently, our research indicates that the speed of light is not constant but variable. However, this insight does not contradict the laws of physics or empirical evidence. Moreover, we propose a new dimensionless constant,nc = 299,792,458, to replace the traditional constant of light speed, c. This novel constant is consistent with all observed measurements of light speed conducted within the observer's local time flow. Although this interpretation of light speed deviates from Einstein's theory, it is grounded in solid theoretical and empirical evidence.