In 1887 the Michelson-Morley experiment was performed, which was supposed to detect the motion of the Earth relative to the ether, i.e., the medium in which light would manifest itself, and therefore the only one relative to which its speed could be truly isotropic.But the experiment found that the speed of light is isotropic relative to the Earth too, and therefore did not detect any motion relative to the ether.In order to justify this negative result, Lorentz hypothesized that all objects that move in the ether undergo a slowing down of time and a length contraction in the direction of motion, thus making the speed of light appear isotropic, while in reality it is not.Instead, Einstein justified this result by arguing that light propagates in a vacuum and that its speed is isotropic in all reference frame, regardless of the motion between them, specifying however that this is a stipulation and, therefore, an apparent but not real phenomenon. But later he considered this isotropy as real. And this is how relativists still consider it, overbearingly, since they do not accept discussions on this statement.In truth, it is precisely thanks to the real slowing down of time and the real contraction of matter that the speed of light appears isotropic. And it is a very useful appearance, because considering it as real has allowed the development of the law of gravitation of General Relativity (which is also apparent) and, above all, to make the GPS system work. Which cannot work according to reality, because the precise speed of the Earth relative to the ether is not known and, therefore, not even the real speed of light relative to the Earth, which would be needed to make the GPS work according to reality.But, as I will demonstrate in this article, this appearance does not allow us to calculate the speeds and distances of celestial objects, too. So, using it anyway, relativists have obtained a complicated and incompatible with observation model of Universe, whose expansion is accelerating.So I developed a theory, which I called Space Quanta in Expansion, which considers the appearance useful for gravitation and GPS, but not for calculating distances and velocities of distant celestial objects, where it uses its own formulas. And so I obtained a model of Universe that is reasonable and compatible with observations and quantum mechanics, whose expansion results in deceleration.