Evolution of the Physical Universe Before the Emergence of Life

Discussion

Leonid Grinin:

"The formation of modern structure of the Universe lasted for many billions of years when our Universe ‘lived’ for quite a long period of time without any stars, galaxies, Hubble's law, clusters and superclusters of galaxies (Khvan 2008: 302). Now it is recognized that the first stars and galaxies turn out to have emerged much earlier. According to the latest astronomical observations, the first galaxies emerged not later than several hundred million years after the Big Bang. In what follows we will consider this in detail. What was the matter from which they had emerged?

* Tiny Material for the Formation of Giants: About the Gas-Dust Clouds and Cosmic Dust

Approximately 270,000 years after the Big Bang, a large phase transition occurred resulting in the emergence of matter in the form of atoms of hydrogen and helium. Later, they started to consolidate in new structures. The main mass of this matter concentrated in gas-dust clouds that could be of tremendous sizes (dozens parsecs, or even more).[1] At present we usually speak of such cosmic fractions as interstellar gas and cosmic dust. They can be both in vacuum condition and in the form of clouds. But as is known the observed today clouds consist mainly of equal proportions of gas and dust. That is why they are usually called gas-dust clouds.

For the first time we observe Nature in the role of a constructor. Before that, it had formed just the basic elements. Now one could observe the emergence of enormous structures from tiny particles and ‘specks of dust’. Later one could constantly observe similar processes in evolutionary developments: large-scale structures are composed of myriads of minute particles and grains.

Minor factors are also necessary for structuring. The formation of clouds (and later of stars and galaxies) involved concentrating of matter on enormous scale, which could have been caused only by gravity. However, this only force is insufficient for structuring, because in ‘an absolutely homogenous universe the emergence of large-scale structures (galaxies and their clusters) is impossible’ (Dolgov et al. 1998: 12–13). Thus, certain ‘seed grains’ are needed, similar to the process of formation of rain drops emerging around particles of dust or soot; or the formation of a pearl around grit.

Small fluctuations are often needed for the powerful forces to start working. Actually, minor fluctuations (minute deviations from homogeneity and isotropy) occurred in the Universe from the first nanoseconds after the Big Bang. Then the larger fluctuations happened. They could act as seed grains for the formation of galaxies. However, it is not clear what kind of fluctuations caused the formation of galaxies and what the mechanism of their formation is. In other fields of evolution initial fluctuations also often remain a mystery.

Thus, the non-uniformity (including the non-uniformity connected with different concentration) is one of the main foundations of development and evolution at all its stages and in all its forms. Any major evolutionary shift in biological and social matter at a certain stage of evolution is necessarily connected with some form of accumulation or concentration when matter becomes abundant and occupies certain niches (the periods which are similar to the first stages after the Big Bang). The higher the stage of evolution, the more important it is. Thus, in a large-scale system the common processes may proceed in their usual way, whereas in the concentration zone some peculiar processes start (as it takes place in the stellar formation zones).

* The Epoch of Formation of the Large-Scale Structure of the Universe. First Galaxies and Stars

Dark and light matter. Nowadays it is generally accepted that dark matter plays an important role in the formation of the first galaxies, as it appeared capable of much quicker consolidation into clusters than the light (baryonic) matter. The latter could not condense until the end of the hydrogen recombination (atom formation) due to radiation pressure (270,000 years after the Big Bang). Only when hydrogen nuclei and electrons were able to merge and form atoms, whereas photons separated from the matter and flew away, the radiation pressure dramatically decreased to zero. As a result, the light matter would fall in potential holes prepared by the dark matter. Perhaps, we observe here a very interesting evolutionary pattern. Nevertheless, the non-evolutionary dark matter initially appeared to be more capable to structuring than the light matter, but the progress of the former toward structuring turned out to be very short and almost leading to a dead-lock. However, as with any evolutionary dead end, this does not mean an absolute stagnation. At present, in galaxy halos the dark matter continues structuring in certain smaller structures, the so-called clumps and sub halos (see, e.g., Diemand et al. 2008). Meanwhile, the evolutionary potential of the light matter was based on the ‘achievements of the dark matter’. Such a model of development is rather typical for evolution. For example, long before the transition to agriculture some gatherers of cereal plants invented many things (including tools, granaries, and grinding stones) that later turned to be rather useful for agriculturalists, but the hunter-gathering mode still turned out to be an evolutionary dead end.

There are rather diverse opinions on the timing and characteristics of the process and sequence of formation of stars, galaxies, galaxy clusters and superclusters.

The galaxy protoclusters are supposed to have been the first to originate. As Ph. J. E. Peebles (1980: 389–390) notes, ‘The same process could operate on a larger scale, the first generation of gas clouds being protoclusters that fragmented to form galaxies, some clusters dissolving to produce field galaxies. A sequence of this general sort has appealed to many authors’. Such phenomena take place at higher levels of evolution when something general is formed (which will turn into a larger taxon in future) that later differentiates into primary level taxa. The species and classes in biology form in this way. The same refers to a society: at first there emerge rather large formations such like families of languages and then the languages, ethnic super-groups and then ethnoses, and sometimes large early empires or states; and afterwards within their framework statehood goes one or two levels down. In other words, there emerges a non-differentiated large structure which is capable to produce a great number of peculiar structures.

However, a more commonly held hypothesis suggests that protogalaxies (in the form of giant condensed gas clouds) were the first to emerge within the structure of the Universe, and later they became the birthplace for individual stars and other structural elements (see, e.g., Gorbunov and Rubakov 2012: 27). However, in recent years new evidence has come to hand to support the idea that those were the stars that appeared first. This discovery somehow modified the previous theories. As a result, at present it is widely accepted that the stars were first to emerge, but those were the giant stars, much more massive than most of the later-formed ones (May et al. 2008). Because of the absence of carbon, oxygen and other elements that absorb the energy from condensing clouds, the process proceeded more slowly in that epoch; thus, only giant clouds could condense producing massive stars hundreds times larger than the Sun (Ibid.). Nowadays there are also such giants of 100–200 solar masses but they are considered unstable (see Surdin and Lamzin 1992). We will see below that the larger is star, the shorter is its life. Thus, such giant stars lived only a few million years. In addition, the first stars contained a small amount of heavy elements. Thus, more than one generation of stars could change, until the quantity of heavy elements gradually increased. The emergence of ‘heavy elements’ from the ‘dead star stellar remnants’ resembles the formation of fertile soil from the remnants of dead plants. The circulation of matter in the Universe is always observed everywhere and at all levels.

In recent years we have witnessed the discovery of a few galaxies that are claimed to be the oldest in the Universe. Meanwhile, the dates of formation of the first galaxies are shifted closer and closer to the Big Bang. The emergence of the first galaxies is dated to less than 400 million years after the Big Bang; and there are even claims that some more ancient galaxies have been discovered. They are claimed to have emerged only 200 million years after the Big Bang.[2]

The evidence on the first stars refers to c. 150–200 million years after the Big Bang; hence, stars and galaxies appear to have emerged almost simultaneously. Since that time depending on its density the matter in the Universe coexists in three main types: in dense state in celestial bodies, in rarefied state in the clouds of different size, and in low-density state (in tens of times compared to the clouds) in interstellar gas.

* THE ERA OF THE STAR-GALAXY STRUCTURE OF THE UNIVERSE

The formation of galaxies and their clusters, as well as of stars and other celestial bodies was the longest evolutionary process that had ever taken place in the Universe. At present we observe that this process is still going on alongside changes and disappearance of galaxies and stars. During the first eight billions years, the formation of huge diversity of stellar bodies and new heavy elements took place in the Universe until about 5–4.5 billion years ago there the conditions were formed for the formation of stellar (Solar) system. On one of its planets there started new geological, chemical and biochemical processes."

(https://www.sociostudies.org/almanac/articles/cosmic_evolution_and_universal_evolutionary_principles)