1. The Evolution of Atoms

1.5 The Homogeneity of the Universe

A perfectly homogeneous universe composed solely of hydrogen, photons and other elementary particles would have been unsuitable to support the emergence of Life. On the other hand, one may envisage a hierarchy of structures where sizes go from microns to millimeters and others where all sizes are exceedingly large. Neither of these structures would be suitable for Life to blossom. Appropriate structures must appear in order to create Life. The universe presents an extraordinary configuration: stars are assembled into galaxies, which are flat objects. Galaxies are themselves assembled into flat clusters, separated from other clusters by large stretches of emptiness, yet they are assembled in superclusters which appear as planes, separated from each other by large stretches of emptiness, that itself makes up 90% of the visible Universe.

How could a hierarchy so rich in various structures have arisen from a uniformly homogeneous primeval state? How has complexity been born from the initial simplicity? On the other hand, structures such as earth, moon and sun must be able to evolve in a stable environment where direct hits and near-impacts are reduced to a minimum.

Severe early non-homogeneities would have, thanks to gravity, grown in later times and we would be able to observe them. They are however nonexistent. Today’s universe is thus the product of an earlier situation where homogeneity was much more pronounced than today.

A few milliseconds after the silent initial explosion (silent because there was no air to propagate the sound) the temperature of the universe was a few hundred million degrees Kelvin. At these temperatures, photons destroy all hydrogen atoms they encounter. This situation existed during the first 300,000 years of the existence of the universe and the creation of local excessive non-homogeneities within the primeval texture of the universe was thereby substantially hindered.

As soon as the temperature dropped, due to the expansion, matter and radiations began to live separate lives. As a consequence, gravity could begin to play a role and provoke the formation of aggregations of matter. Those initial aggregations that had survived the destructive activity of photons and whose size was superior to 50 million light-years, could now grow unhindered and form galaxial clusters and superclusters.

The explanation here given for the small irregularities appearing in a homogeneous texture is however not completely satisfactory. Astronomers are not happy with it on account of the following discrepancy: the visible part of the universe extends over 13.5 to 15 billion light-years. The extravagant distances considered by astronomers are such that parsecs are not adequate to represent them. Z is another cosmologist’s shortcut. Z is the factor that measures the red shift -the Doppler effect- that light undergoes due to the universal expansion. This shift indicates, altogether, the distance and the time that elapsed between the moment of emission of light and its reception on earth. 1 Z equates 1.533 x 106 Parsecs. Clouds and stars are detected at a distance of Z = 4.4. The red shifts of the most distant galaxies are Z = 5 to 7. They must have formed just a few million years after the universe itself. If one travels in the reverse direction, the universe should have had already a size of about 100 million light-years, about 300,000 years after the Big Bang. This is much larger than it is supposed to be if its size had increased regularly and in an ordained way from the moment of the explosion. A formidable inflation must have occurred sometime, not only to resolve the discrepancy and therewith satisfy our deductions but also to dilute out some heavy matter that would almost certainly have provoked already a contraction and collapse into a Universal Black Hole: the universe was initially composed not only of neutrons, photons, electrons etc. but also of magnetic monopoles. These monopoles are supposed to have a mass 1017 that of photons and their total density would exceed the critical density by a factor 1015. They are a strong factor of non-homogeneity and collapse of the universe. This is obviously not the case, presumably because they have been diluted out.

These observations lead to the hypothesis that between 10-40 and 10-36 seconds after the Big Bang, when the temperature was about 1028 degrees, a formidable inflation of the universe occurred, wherewith its size increased at once by a gigantic factor of 101,000,000. This inflation diluted the monopoles out, increased the initial homogeneity of space by a factor of 101,000,000, made the homogeneity universal, discarded the menace of a premature contraction of matter into a Black Hole and allowed the prompt formation of galaxies and stars, within a few hundred million years.

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