Hubble's Law is currently formulated as follows: Vr = HR , where Vr is the galaxies' mutual recession speed, R the varying mutual distance, and H is a constant of proportionality known as Hubble Constant.
Used in this form, Hubble's Law - along with some analytical implications of Einstein's field equations - has led most astrophysicists and cosmologists to assume that the universe is expanding, and that the expansion had to start from a unique point of almost infinite concentration/density of mass/energy, i.e., from a place in which the ?mutual distance? between any kind of matter components (if any) was Ro ≈ 0 Then, according to most cosmologists, something like a huge explosion (the ?big bang?) can explain the initial tremendous force that caused the expansion of the universe. (According to Russian mathematician Alexander Friedmann (1888-1925), Einstein's chronotope is possible of both expansion and contraction).
Other supporters of the big-bang theory do now incline to think of the ?big-bang? not as of an explosion, but only as of the beginning of the universe's expansion, though I cannot grasp what they mean for ?big-bang? or any other ?more appropriate? dubbing of the event. In any case, big-bang theories adopt General Relativity as their basic reference paradigm.
Belgian astronomer George Lema?tre (1894-1966) was the first theorist of the universe's expansion, this viewed as originating from a ?primeval super-atom?. Lema?tre availed himself of General Relativity and of Hubble's statistics concerning the observed correlation between distance and mutual recession speed of galaxies. Subsequently, Dutch astronomer Willem De Sitter (1872-1934) did also theorize the expansion of the universe, adopting both Hubble's observational data and (sic!) Einstein's arbitrary ?cosmological constant? that a repented Einstein had later to label as his ?greatest blunder?.
Through recent decades the theoretical framework of big-bang theories developed and underwent several changes with a number of ad-hoc adjustments, because of astronomic observations incompatible with theoretical statements and predictions. The sequence of the adjustments had even led theorists of the universe's expansion to the need for considering Hubble coefficient H no more as a ?constant? but as a cosmological parameter that varies with time.
This essay of mine is based on my intent to avoid any reference to both Newtonian and Einsteinian cosmological models. As to me, Hubble constant is only the coefficient of a statistical linear correlation between two sets of observed data, i.e., between mutual distances and recession speeds of galaxies. I have no intention to attach any other significance to Hubble's statistical correlation, so that constant H, as a ?statistical coefficient?, shall be considered as a modifiable constant only upon more accurate and unbiased astronomical observations, which inevitably imply refinements in the identification of the most appropriate value for H. If the sequence of future observations corroborates the linearity of Hubble's correlation, this statistical law should be accepted as an experimental law, from which one can draw logical deductions as well as observational predictions. Therefore, I deem it improper and I reject all efforts to bend Hubble's law to the needs of abstract and questionable cosmological theories. What follows is a way to analyze Hubble's law with the only purpose of giving its simple logical implications the due evidence, with no need for either relativistic or other kind of cosmological reference and interpretation.
Upon this basis, it's easy to prove that, when t = 0 (i.e., at the supposed beginning of the universe's expansion), not only could not Ro be nil, but also that the initial distance between galaxies under formation had to be several million light-years. Moreover, a logical implication of Hubble's law predicts that the galaxies' recession acceleration too (i.e., ar = H Vr = H2 R) increases with the recession speed and distance, as observed and confirmed during recent years. Which is also an observational confirmation of the reliability of Hubble's law in the form it was originally formulated.
Additional notes, in a close connection with the text of the relative book , regard the formation of shape and dynamics of galaxies as due to the rise of vortices of physical space (i.e., vortices of "plenum", the Universe's basic and undetectable fluid continuum) around "cores" of nothingness.
