The emergence of planetary systems is a necessary condition for the further evolution of the matter of the Universe. Today we will figure out how planetary systems arise.
Judging by the amount of metals contained in the composition of our Sun and the number of solid planets in the solar system, we can conclude that the solar system was formed from a cloud of gas and dust evolved stars of the second generation (
Some of the stars of the local group, including the solar system, were formed from this cloud of gas and dust.
After evolving, the stars of the second generation synthesized a sufficient amount of heavy elements to create stable planetary systems.
4.6 billion years ago, in a gas-dust cloud (consisting of the remnants of second-generation stars), under the gravitational influence of a dark mother, a gravitational well began to form, into which matter rushed. Gravitational compression reduced the size of the cloud, increasing its rotation speed. The constantly increasing speed of rotation significantly affected the uniformity of compression of matter in the center, which led to the formation of a flat disk with a dense and hot core in its center.
By this time, the concentration of matter in the center of the cloud had reached the limit necessary for the formation of a protostar.
A protostar is a young, recently formed star, in which there are not enough conditions (for example, temperature in the center) for the occurrence of the process of thermonuclear reactions; it receives its energy as a result of gravitational compression.
The protostar emits a strong stellar wind, as a result of which some of the matter is thrown out of the system back into interstellar space.
The stellar wind, coupled with a rotating dust cloud accelerated to such an extent that matter is actually in orbit around the protostar, generates accretion processes in the gas and dust cloud. The density of the cloud at this stage is still quite high, and any inhomogeneity generates gravitational wells in the cloud, where matter tends.
The gas-dust cloud, being in the orbit of the protostar, practically does not fall on the protostar, since the orbital velocity of the particles is already high enough (the “falling” matter at that moment only 0.1-0.001% of the mass of the protostar remained). But, taking into account the initiated processes of accretion and further gravitational compression of matter in the orbit of the protostars, very soon (after about ten million years) new celestial bodies — planets — begin to form from this already protoplanetary disk (protodisk).
The formation of planets occurs due to stones (consisting mainly of dust), which collide with each other within their gravitational fields, finally forming the appearance of future planets and their satellites. The formation goes on until the mutual gravity of the formed planets no longer exerts any significant influence on the further formation. From this moment on, any collisions are already accidental.
The protostar itself takes from 50 million to 100 million years after formation to condense and bring the temperature and pressure in the center of its core to the necessary criteria for triggering a thermonuclear reaction. The proton-proton cycle, previously mentioned in the last article, will be the main source of energy for the next billions of years.
The formation of stellar systems can be attributed to the next stage of self-organization and the complication of the structure of matter, because this has never happened before in the Universe.
According to generally accepted scientific theories, thermonuclear reactions in our Sun started before our planet was formed.
The formation of planet Earth as a unique object of the solar system, on which life exists (active form of matter), is a separate story and we will talk about it in the next article.
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