General Theory for Light Propagation and the Motion of Bodies with Mass

100 years ago, A. Einstein presented to the scientific world the so-called Theory of Relativity ((1905) Special Relativity Theory, (1916) General Relativity Theory). One of the essential aspects of this theory has become the holy grail of modern physics: "The speed of light in the vacuum is constant". In the last century, this concept caused passionate controversies in the scientific world for its implications on how the universe works, its origin, and its possible end. So the idea that the speed of light can be variable, and consequently the Theory of Relativity not correct, currently it is considered problematic because this idea perhaps fails to explain the wide range of modern tests of general relativity, like the dynamics of the Binary Pulsar and the detection of gravitational waves. The observations of Edwin Powell Hubble (1929) allowed determining other characteristics of light propagation. Hubble observed that the light that reaches us from distant stars has spectral lines that are red-shifted all the more the far-away the star is from us. The Theory of Relativity along with Hubble's observations laid the formulations for another conclusion that marked our current understanding of how the universe works: the universe had an origin, called the big-bang, approximately 13.5 billion years ago. The recent launch of the James Webb Space Telescope has as one of its main objectives to observe the birth of the universe. The conclusion that the universe has had a beginning may perhaps be the result of a conception of how we see nature, everything we know has a beginning and an end! The conclusion that the universe has also had a beginning may be wrong and therefore we can see the need to explain the existence of an infinite universe that has no beginning and will have no end. This article proposes a new theory that explains how the universe works where the observations concerning the "red-shift" are explained by a new property of light called "SLIDING" which increases the wavelength of light. The wavelength increases are only significant over very large propagation distances (million light-years), which is why the change in the wavelength was not observed in the Michelson/Morley experiments. The increase in the wavelength is done without changes in the photon energy. The proposed new property of our universe called "SLIDING" also affects bodies in motion. In proof of the aforementioned, in this article, it is demonstrated that SLIDING can explain the perihelion's precession in the orbits of the planets. As a result of the proposed theory, the universe did not have an event that we can call as it birth, it has always existed and will exist forever. The Olbers?s paradox is avoided because the light that reaches us from distant stars has a wavelength in the infrared.