In 1887 the famous Michelson-Morley experiment was carry out, which should have revealed that the speed of light is not isotropic and, therefore, the so-called ether wind. But the experiment revealed that the speed of light result isotropic and subsequently no aether, either.In order to justify this negative result, Lorentz hypothesized that all objects that move in the aether, undergo a contraction in the direction of motion, for which the arm of the Michelson-Morley interferometer would have contracted, thus making the speed of light result isotropic, while in reality it was not.However, in 1905 Einstein intervened, that did not accept Lorentz's justification, eliminated the need for the aether and formulated the theory of Special Relativity, whose second postulate states that "The velocity of light in empty space always has its standard value, independent of the motion of the source or receiver of light" and, consequently, that it would be isotropic in all inertial frames of reference.But Lorentz, despite Einstein's constant attempts to convince him, continued to support his thesis until his death.In fact, through a wise use of the transformations that bear his name, he managed to frame in his theory of the immobile ether those phenomena that seemed to imply an apparent partial or total dragging of the ether. While admitting the greater simplicity of Einstein's theory, Lorentz do not accepted it, not intending to give up some fundamental principles on which two centuries of classical physics were based.Because it had been demonstrated that light is a wave phenomenon which, therefore, needs a medium to manifest itself, so that its speed can be isotropic only with respect to said medium and therefore not also with respect to a moving inertial frames of reference compared to the medium.Shouldn't this reasoning have been enough to agree with Lorentz?Instead, it was Einstein's theory that prevailed over Lorentz's!But if the Cosmic Microwave Background Radiation and its dipole anisotropy had already been observed then, who would have won?Lorentz would have won, because he could have demonstrated not only that the speed of light cannot be isotropic on the Earth, but also the speed of the Earth with respect to the ether, thus invalidating the second postulate of the theory of Special Relativity and, consequently, even the theory itself.Which I propose to do through two demonstrations.