Models of the universe in modern cosmology. Cosmological models of the universe. What is the future of our universe? Friedman proposed three models for the development of the universe

Cosmology studies the physical nature, structure and evolution of the Universe as a whole.

The concept of "Universe" means the Cosmos accessible to human observation.

Cosmology considers the most general properties of the entire region of space covered by observation. We call it the Metagalaxy. Our knowledge of the Metagalaxy is limited to the observation horizon. This horizon is determined by the fact that the speed of light is not instantaneous. Consequently, we can observe only those regions of the Universe from which light has managed to reach us by now. In this case, we see objects not in their current state, but in the one in which they were at the time of the emission of light.

Models of the Universe, like any other, are built on the basis of theoretical concepts that currently exist in cosmology, physics, mathematics, chemistry and other related disciplines.

Several prerequisites for studying the Universe:

It is believed that the laws of the functioning of the world formulated by physics operate in the entire Universe;

It is believed that the observations of astronomers also extend to the entire universe;

It is believed that those conclusions are true that do not contradict the existence of man (anthropic principle).

The conclusions of cosmology are called models of the origin and development of the Universe.

The problems of the origin and structure of the Universe have occupied people since antiquity. Despite the high level of astronomical knowledge of the peoples of the ancient East, their views on the structure of the world were limited to direct visual sensations. Therefore, in Babylon there were ideas according to which the Earth looks like a convex island surrounded by an ocean. Inside the Earth, as if there is a "kingdom of the dead." The sky is a solid dome resting on the earth's surface and separating the "lower waters" (the ocean flowing around the earth's island) from the "upper" (rain) waters. On this dome are attached heavenly bodies, gods seem to live above the sky. According to the ideas of the ancient Egyptians, the Universe looks like a large valley, elongated from north to south, in the center of which is Egypt. The sky was likened to a large iron roof, which is supported on pillars, on which stars are suspended in the form of lamps.

Heraclid of Pontus and Eudoxus of Cnidus in the 4th century BC claimed that all bodies in the Universe rotate around their axis, and revolve around a common center (Earth) in spheres, the number of which in different cosmogony varied from 30 to 55. The top of this picture of the world was the system of Claudius Ptolemy (II century AD ).

The first scientifically based models of the Universe appeared after the discoveries of Copernicus, Galileo and Newton. First, R. Descartes put forward the idea of an evolutionary vortex Universe. According to his theory, all space objects were formed from primary homogeneous matter as a result of vortex movements. solar system, according to Descartes - one of the whirlwinds of cosmic matter. I. Kant developed the idea of an infinite Universe formed under the influence of mechanical forces attraction and repulsion, and tried to find out the further fate of such a universe. The great French mathematician Laplace described Kant's hypothesis mathematically.

I. Newton believed that the gravitating universe cannot be finite, since in this case all the stars that make it up, under the influence of gravitational forces, will gather in the center. He tried to explain the observed contradiction by the infinite number of stars in the Universe, as well as the infinity of the world in time and space. However, cosmology then ran into paradoxes.

1. Gravitational paradox: according to the Newtonian concept of gravity endless space with a finite mass density should give an infinite attractive force. Infinitely increasing gravitation inevitably leads to infinite accelerations and infinite speeds of cosmic bodies. Therefore, the speed of the bodies must increase with increasing distance between the bodies. But this does not happen, and then it turns out that the Universe cannot exist forever.

Solving this problem, I. Kant concluded that the Cosmos is non-static. He called the nebulae "world islands". Lambert developed Kant's ideas. In his opinion, with an increase in the size of the islands, the distance between them also increases so that the total forces of the Cosmos remain finite. Then the paradox is resolved.

2. Photometric paradox (Olbers paradox): with an infinite universe filled with an infinite number of stars, the sky should be uniformly bright. In fact, no such effect is observed. In 1823, Olbers showed that dust clouds that absorb the light of more distant stars heat up themselves and must therefore emit light. This paradox resolved itself after the creation of a model of the expanding universe.

Modern cosmology arose after the advent of Einstein's general theory of relativity and therefore, in contrast to classical Galilean and Newtonian cosmology, it is called relativistic. The empirical basis for cosmology is optical and radar astronomical observations. The discovery of elementary particles and the study of their behavior on accelerators under conditions close to those that existed at the initial stages of the development of the Universe helped to understand what happened in the first moments of its evolution.

When Einstein was working on his general theory of relativity, scientists didn't see the universe as it is now. The Metagalaxy and its expansion had not yet been discovered, so Einstein relied on the idea of a stationary Universe, which is evenly filled with galaxies located at constant distances. Then inevitably followed the conclusion about the compression of the world under the influence of gravity. This result was in conflict with the conclusions of general relativity. In order not to conflict with the generally accepted picture of the world, Einstein arbitrarily introduced into his equations new parameter- cosmic repulsion, which was characterized by the cosmological constant. A. Einstein assumed that the Universe is stationary, infinite, but not unlimited. That is, it was conceived as a sphere, constantly increasing in volume, but having boundaries.

The only person who in 1922 believed in the correctness of the conclusions of general relativity as applied to cosmological problems was the young Soviet physicist A.A. Friedman. He noticed that the non-stationarity of the curvature of space follows from the theory of relativity.

As already mentioned in the first part of this paper, the Friedman model is based on the concept of an isotropic, homogeneous, and non-stationary state of the Universe.

Isotropy indicates that there are no distinguished points of directions in the Universe, that is, its properties do not depend on direction.

The uniformity of the Universe characterizes the distribution of matter in it. This uniform distribution of matter can be substantiated by counting the number of galaxies up to a given apparent magnitude. According to observations, the density of matter in the part of space that we see is on average the same.

Non-stationarity means that the Universe cannot be in a static, unchanging state, but must either expand or contract

In modern cosmology, these three statements are called cosmological postulates. The totality of these postulates is the fundamental cosmological principle. The cosmological principle follows directly from the postulates of the general theory of relativity.

A. Friedman, on the basis of the postulates put forward by him, created a model of the structure of the Universe, in which all galaxies move away from each other. This model is similar to a uniformly inflated rubber ball, all points of space of which are moving away from each other. The distance between any two points increases, but none of them can be called the center of expansion. Moreover, than more distance between points, the faster they move away from each other.

Friedman himself considered only one model of the structure of the Universe, in which space changes according to a parabolic law. That is, at first it will slowly expand, and then, under the influence of gravitational forces, the expansion will be replaced by compression to its original size. His followers showed that there are at least three models for which all three cosmological postulates hold. A. Friedman's parabolic model is one of the possible options. A slightly different solution to the problem was found by the Dutch astronomer W. de Sitter. The space of the Universe in his model is hyperbolic, that is, the expansion of the Universe occurs with increasing acceleration. The expansion rate is so great that the gravitational influence cannot interfere with this process. He actually predicted the expansion of the universe. The third variant of the behavior of the Universe was calculated by the Belgian priest J. Lemaitre. In his model, the universe will expand to infinity, but the rate of expansion will constantly decrease - this dependence is logarithmic. In this case, the expansion rate is just enough to avoid shrinking to zero.

In the first model, space is curved and closed on itself. It is a sphere, so its dimensions are finite. In the second model, the space is curved differently, in the form of a hyperbolic paraboloid (or saddle), the space is infinite. In the third model, with a critical rate of expansion, space is flat, and therefore also infinite.

Initially, these hypotheses were perceived as an incident, including by A. Einstein. However, already in 1926 an epoch-making event in cosmology took place, which confirmed the correctness of the calculations of Friedman - De Sitter - Lemaitre. Such an event, which influenced the construction of all existing models of the Universe, was the work of the American astronomer Edwin P. Hubble. In 1929, while conducting observations on the largest telescope at that time, he found that the light coming to Earth from distant galaxies shifted towards the long-wavelength part of the spectrum. This phenomenon, called the "Redshift Effect", is based on the principle discovered by the famous physicist K. Doppler. The Doppler effect indicates that in the spectrum of a radiation source approaching the observer, the spectral lines are shifted to the short-wave (violet) side, in the spectrum of a source moving away from the observer, the spectral lines are shifted to the red (long-wave) side.

The redshift effect indicates the distance of galaxies from the observer. With the exception of the famous Andromeda Nebula and a few star systems closest to us, all other galaxies are moving away from us. Moreover, it turned out that the speed of expansion of galaxies is not the same in various parts Universe. They move away from us the faster, the farther they are located. In other words, the redshift turned out to be proportional to the distance to the radiation source - this is the strict formulation open law Hubble. The regular relationship between the speed of removal of galaxies and the distance to them is described using the Hubble constant (H, km/sec per 1 megaparsec of distance).

where V is the removal rate of galaxies, r is the distance between them.

The value of this constant has not yet been definitively established. Various scientists define it in the range of 80 ± 17 km / s for each megaparsec of distance.

The phenomenon of redshift was explained in the phenomenon of "recession of galaxies". In this regard, the problems of studying the expansion of the Universe and determining its age from the duration of this expansion come to the fore.

According to all three models of the evolution of the Universe, it had a reference point - a state characterized by a zero moment of time. The initial state of matter in it was some superdense state, which was characterized by instability, which led to its destruction. As a result, the matter of the universe began to rapidly scatter. Now we know that for every billion years of life the Universe expands by 5 - 10%. The most probable value of the Hubble constant of 80 km/sec gives us expansion times ranging from 13 to 17 billion years. In 2002, using a computer model of the current state of the universe, results were obtained giving us a lifetime of 13.7 billion years.

The mechanism of further evolution depends on the average density of matter in it. The critical density of a substance corresponds to a value of 3 hydrogen atoms in 1 m3 of space. However, the uncertainty in modern meaning The density of matter in the universe is very high. If we sum up the masses of all currently known galaxies and interstellar gas, we get the value Accordingly, the universe can expand forever.

However, there is the so-called hidden mass problem. Perhaps scientists do not know all the matter in the universe. According to the latest data, the observed mass of the Universe is only 5-10% relative to the total mass of matter. If this result is confirmed, the evolution of the Universe may take a different path. Various cosmic objects claim to be the hidden mass carriers of the Universe. In our and other galaxies, there is a large amount of dark matter that cannot be seen directly, but whose existence we learn from its gravitational influence on the orbits of stars. Moreover, even more such matter is contained within galactic clusters. This matter is a vacuum quantum mechanical structure. 75% of the hidden mass falls on its share.

Neutrinos, particles formed in the early stages of the development of the universe, can claim the role of carriers of the hidden mass. As it became known in the last 3 years, neutrinos still have a mass, therefore, they can participate in the formation of gravitational interactions.

Candidates for the same role are also some exotic objects, such as black holes - objects of point size and huge mass, which are contained in the universe in large quantities, spatial string objects, etc.

According to a number of scientists, 20% of the hidden matter is represented by "mirror particles", which make up the "mirror world" invisible to us, which permeates our Universe. There are enough hypotheses on this score, but their confirmation or refutation is a matter for the future.

If the assumptions of scientists about the mass of the matter of the Universe unknown to us are confirmed, then its evolution can go along the path proposed in the Friedman model, or according to the scheme of the Pulsating Universe. In this model, the Universe goes through an infinite number of oscillations, that is, at the end of each life cycle, it returns to its original state with a point volume and an infinitely high density.

Very important issue modern cosmology are the initial moments of the existence of our universe. A successful attempt to solve this problem is associated with the name of the American astrophysicist Georgy Antonovich Gamow, who in 1942 proposed the concept of the evolution of the Universe through the Big Bang. The main goal of the author of the concept was to consider nuclear reactions at the beginning of the cosmological expansion, to obtain the ratios observed in our time between the number of different chemical elements and their isotopes. The theory of the Hot Universe and the Big Bang gives certain predictions about the state of matter in the Universe in the first moments of its life.

1. Basic cosmological models of the Universe

Modern physics considers the mega world as a system that includes all celestial bodies, diffuse (diffusion - scattering) matter that exists in the form of separated atoms and molecules, as well as in the form of denser formations - giant clouds of dust and gas, and matter in the form of radiation.

Cosmology is the science of the universe as a whole. In modern times, it is separated from philosophy and becomes an independent science. Newtonian cosmology was based on the following postulates:

The Universe has always existed, it is the “world as a whole” (the universe).

The universe is stationary (unchanging), only space systems but not the world as a whole.

· Space and time are absolute. Metrically, space and time are infinite.

· Space and time are isotropic (isotropy characterizes the sameness of the physical properties of the medium in all directions) and homogeneous (homogeneity characterizes the average distribution of matter in the Universe).

Modern cosmology is based on the general theory of relativity and therefore it is called relativistic, in contrast to the former classical one.

In 1929, Edwin Hubble (an American astrophysicist) discovered the "red shift" phenomenon. Light from distant galaxies is shifted towards the red end of the spectrum, indicating that the galaxies are moving away from the observer. The idea of the non-stationarity of the Universe arose. Alexander Alexandrovich Fridman (1888 - 1925) was the first to theoretically prove that the Universe cannot be stationary, but must periodically expand or contract. The problems of studying the expansion of the Universe and determining its age have come to the fore. The next stage in the study of the universe is associated with the work of the American scientist Georgy Gamow (1904-1968). The physical processes that took place at different stages of the expansion of the Universe began to be investigated. Gamow discovered "relic radiation". (A relic is a remnant of the distant past).

There are several models of the Universe: common to them is the idea of its non-stationary, isotropic and homogeneous character.

According to the mode of existence - the model of the "expanding Universe" and the model of the "pulsating Universe".

Depending on the curvature of space, they distinguish - an open model in which the curvature is negative or equal to zero, it represents an open infinite Universe; closed model with positive curvature, in which the Universe is finite, but unlimited, limitless.

The discussion of the question of the finiteness or infinity of the Universe gave rise to several so-called cosmological paradoxes, according to which, if the Universe is infinite, then it is finite.

1. Expansion paradox (E. Hubble). Accepting the idea of infinite extension, we come to a contradiction with the theory of relativity. Removal of the nebula from the observer to an infinite distance (according to the theory of "red shift" by V.M. Slifer and the "Doppler effect") must exceed the speed of light. But it is the limiting (according to Einstein's theory) speed of propagation of material interactions, nothing can move faster.

2. Photometric paradox (J.F. Chezo and V. Olbers). This is the thesis about the infinite luminosity (in the absence of light absorption) of the sky according to the law of illumination of any site and according to the law of the increase in the number of light sources as the volume of space increases. But the infinite luminosity contradicts the empirical data.

3. Gravitational paradox (K. Neumann, G. Seeliger): an infinite number of cosmic bodies should lead to infinite gravitation, and therefore to infinite acceleration, which is not observed.

4. Thermodynamic paradox (or the so-called "thermal death" of the Universe). The transition of thermal energy to other forms is difficult compared to the reverse process. Result: the evolution of matter leads to thermodynamic equilibrium. The paradox speaks of the finite nature of the space-time structure of the Universe.

2. Evolution of the Universe. The Big Bang Theory"

From ancient times to the beginning of the 20th century, the cosmos was considered unchanged. The starry world personified absolute peace, eternity and boundless length. The discovery in 1929 of the explosive recession of galaxies, that is, the rapid expansion of the visible part of the Universe, showed that the Universe is non-stationary. Extrapolating this expansion process into the past, scientists concluded that 15-20 billion years ago the Universe was enclosed in an infinitely small volume of space with an infinitely high density (“singularity point”), and the entire current Universe is finite, i.e. has a limited scope and time of existence.

The starting point of the lifetime of the evolving Universe begins from the moment when the "Big Bang" occurred and the state of the singularity suddenly broke. According to most researchers, modern theory The "Big Bang" as a whole quite successfully describes the evolution of the Universe, starting from about 10 -44 seconds after the start of the expansion. The only weak link in this wonderful theory is the problem of the Beginning - the physical description of the singularity.

Scientists agree that the original universe was in conditions that are difficult to imagine and reproduce on Earth. These conditions are characterized by the presence of high temperature and high pressure at the singularity in which matter was concentrated.

The time of evolution of the Universe is estimated at about 20 billion years. Theoretical calculations showed that in the singular state its radius was close to the electron radius, i.e. it was a micro-object of negligibly small scale. It is assumed that the quantum regularities characteristic of elementary particles began to affect here.

The universe went on to expand from its original singular state as a result of the Big Bang, which filled all of space. A temperature of 100,000 million degrees arose. according to Kelvin, at which molecules, atoms and even nuclei cannot exist. The substance was in the form of elementary particles, among which electrons, positrons, neutrinos, and photons prevailed, and there were less protons and neutrons. At the end of the third minute after the explosion, the temperature of the universe dropped to 1 billion degrees. by Kelvin. The nuclei of atoms began to form - heavy hydrogen and helium, but the substance of the Universe by this time consisted mainly of photons, neutrinos and antineutrinos. Only a few hundred thousand years later, hydrogen and helium atoms began to form, forming a hydrogen-helium plasma. Astronomers discovered "relic" radio emission in 1965 - the emission of hot plasma, which has been preserved from the time when there were no stars and galaxies yet. From this mixture of hydrogen and helium, in the process of evolution, all the diversity of the modern Universe arose. According to the theory of J. H. Jeans, the main factor in the evolution of the Universe is its gravitational instability: matter cannot be distributed with a constant density in any volume. The initially homogeneous plasma disintegrated into huge bunches. From them, clusters of galaxies were then formed, which disintegrated into protogalaxies, and protostars arose from them. This process continues to this day. Planetary systems formed around the stars. This model (standard) of the Universe is not sufficiently substantiated, many questions remain. The arguments in its favor are only the established facts of the expansion of the Universe and the relic radiation.

The famous American astronomer Carl Sagan built a visual model of the evolution of the Universe, in which the space year is equal to 15 billion Earth years, and 1 sec. - 500 years; then, in terrestrial units of time, evolution will be presented as follows:

The standard model of the evolution of the Universe assumes that the initial temperature inside the singularity was more than 10 13 on the Kelvin scale (in which the reference point corresponds to -273 0 С). The density of the substance is approximately 10 93 g/cm 3 . Inevitably, a "big bang" was to occur, with which the beginning of evolution is associated. It is assumed that such an explosion occurred approximately 15-20 billion years ago and was accompanied first by a rapid and then by a more moderate expansion and, accordingly, by a gradual cooling of the Universe. According to the degree of expansion of the universe, scientists judge the state of matter at different stages of evolution. After 0.01 sec. after the explosion, the density of the substance dropped to 10 10 g/cm 3 . Under these conditions, in the expanding Universe, apparently, there should have been photons, electrons, positrons, neutrinos and antineutrinos, as well as a small number of nucleons (protons and neutrons). In this case, continuous transformations of electron + positron pairs into photons and vice versa - photons into an electron + positron pair took place. But already 3 minutes after the explosion, a mixture of light nuclei is formed from nucleons: 2/3 hydrogen and 1/3 helium, the so-called prestellar substance, the rest of the chemical elements are formed from it by nuclear reactions. At the moment when hydrogen and helium atoms arise, the substance becomes transparent to photons, and they begin to radiate into world space. At present, such a residual process is observed in the form of relic radiation (a remnant from that distant pore of the formation of neutral hydrogen and helium atoms).

As the Universe expanded and cooled, the processes of destruction of previously existing structures and the emergence of new structures on this basis took place, which led to a violation of the symmetry between matter and antimatter. When the temperature after the explosion dropped to 6 billion degrees Kelvin, the first 8 seconds. there was basically a mixture of electrons and positrons. As long as the mixture was in thermal equilibrium, the number of particles remained approximately the same. Continuous collisions occur between particles, as a result of which photons arise, and from photons - an electron and a positron. There is a continuous transformation of matter into radiation and, conversely, radiation into matter. At this stage, the symmetry between matter and radiation is preserved.

The violation of this symmetry occurred after the further expansion of the Universe and the corresponding decrease in its temperature. There are heavier nuclear particles - protons and neutrons. There is an extremely slight preponderance of matter over radiation (1 proton or neutron per billion photons). From this surplus, in the process of further evolution, that huge wealth and diversity of the material world arises, ranging from atoms and molecules to various mountain formations, planets, stars and galaxies.

So, 15-20 billion years is the approximate age of the Universe. What happened before the birth of the universe? The first cosmogonic scheme of modern cosmology states that the entire mass of the Universe was compressed into a certain point (singularity). It is not known for what reasons this initial, point state was violated and what happened today is called the Big Bang.

The second cosmological scheme of the birth of the Universe describes this process of emergence from "nothing", vacuum. In the light of new cosmogonic ideas, the very understanding of vacuum has been revised by science. Vacuum is a special state of matter. At the initial stages of the Universe, an intense gravitational field can generate particles from the vacuum.

We find an interesting analogy to these modern ideas among the ancients. The philosopher and theologian Origen (II-III centuries AD) mentioned the transition of matter to another state, even the “disappearance of matter” at the moment of the death of the Universe. When the Universe arises again, "matter, - he wrote, - again receives being, forming bodies ...".

According to the researchers' scenario, the entire observable universe of 10 billion light years in size arose as a result of an expansion that lasted only 10 -30 seconds. Scattering, expanding in all directions, the matter moved aside "non-existence", creating space and starting the countdown of time. This is how modern cosmogony sees the formation of the Universe.

The conceptual model of the "expanding Universe" was proposed by A.A. Friedman in 1922-24. Decades later, it received practical confirmation in the work of the American astronomer E. Hubble, who studied the movement of galaxies. Hubble discovered that galaxies are rapidly receding, following some kind of momentum. If this runaway does not stop, if it continues indefinitely, then the distance between space objects will increase, tending to infinity. According to Friedman's calculations, this is exactly how the further evolution of the Universe should have taken place. However, under one condition - if the average mass density of the Universe turns out to be less than a certain critical value, this value is approximately three atoms per cubic meter. Some time ago, data obtained by American astronomers from a satellite that studied the X-ray emission of distant galaxies made it possible to calculate the average mass density of the Universe. It turned out to be very close to that critical mass at which the expansion of the Universe cannot be infinite.

It was necessary to turn to the study of the Universe through the study of X-rays because a significant part of its matter is not perceived optically. About half of the mass of our Galaxy we "can't see". The existence of this substance, which we do not perceive, is evidenced, in particular, by the gravitational forces that determine the movement of our and other galaxies, the movement of star systems. This substance can exist in the form of "black holes", the mass of which is hundreds of millions of masses of our Sun, in the form of neutrinos or some other forms unknown to us. Not perceived, like "black holes", the corona of galaxies can be, as some researchers believe, 5-10 times the mass of the galaxies themselves.

The assumption that the mass of the Universe is much larger than is commonly believed has found a new, very strong confirmation in the works of physicists. They obtained the first data that one of the three types of neutrinos has a rest mass. If the rest of the neutrinos have the same characteristics, then the mass of neutrinos in the Universe is 100 times greater than the mass of ordinary matter found in stars and galaxies.

This discovery allows us to say with greater confidence that the expansion of the Universe will continue only until a certain moment, after which the process will reverse - the galaxies will begin to approach each other, shrinking again to a certain point. Following matter, space will shrink into a point. There will be what astronomers today call the "collapse of the universe."

Will people or inhabitants of other worlds, if they exist in space, notice the compression of the Universe, the beginning of its return to primordial chaos? No. They won't be able to see the reversal of time that will have to happen as the universe begins to contract.

Scientists, speaking about the turn of the flow of time on the scale of the Universe, draw an analogy with time on a shrinking, “collapsing” star. The conditional clock located on the surface of such a star will first have to slow down, then, when the compression reaches a critical point, they will stop. When the star "fails" from our space-time, the conditional hands on the conditional clock will move in the opposite direction - time will go back. But a hypothetical observer who is on such a star will not notice all this. Slowing down, stopping and changing the direction of time could be observed from the outside, being outside the "collapsing" system. If our universe is the only one and there is nothing outside of it - no matter, no time, no space - then there can be no outside view that could notice when time changes course and flows back.

Some scientists believe that this event has already happened in our Universe, the galaxies are falling on each other, and the Universe has entered the era of its death. There are mathematical calculations and considerations that support this idea. What happens after the universe returns to a certain starting point? After that, a new cycle will begin, another “Big Bang” will take place, the pra-matter will rush in all directions, pushing and creating space, galaxies, star clusters, and life will arise again. Such, in particular, is the cosmological model of the American astronomer J. Wheeler, the model of the alternately expanding and "collapsing" Universe.

The well-known mathematician and logician Kurt Gödel mathematically substantiated the position that under certain conditions our Universe must indeed return to its starting point in order to then again complete the same cycle, ending it with a new return to its original state. These calculations also correspond to the model of the English astronomer P. Davis, the model of the “pulsating Universe”. But what is important is that the Davis universe includes closed time lines, in other words, time moves in a circle in it. The number of births and deaths that the universe experiences is infinite.

And how does modern cosmogony imagine the death of the universe? The famous American physicist S. Weinberg describes it this way. After the contraction begins, for thousands and millions of years, nothing will happen that could alarm our distant descendants. However, when the universe shrinks to 1/100 of its current size, the night sky will give the Earth as much heat as the day sky today. In 70 million years, the universe will shrink another ten times, and then "our heirs and successors (if any) will see the sky unbearably bright." In another 700 years, the cosmic temperature will reach ten million degrees, stars and planets will begin to turn into a "cosmic soup" of radiation, electrons and nuclei.

After shrinking to a point, after what we call the “death of the Universe”, but which, perhaps, is not its death at all, a new cycle begins. An indirect confirmation of this conjecture is the already mentioned relic radiation, the echo of the "Big Bang" that gave rise to our Universe. According to scientists, this radiation, it turns out, comes not only from the past, but also "from the future." This is a reflection of the "world fire" emanating from the next cycle, in which a new Universe is born. Not only relic radiation permeates our world, coming as if from two sides - from the past and the future. The matter that makes up the world, the Universe and us, perhaps, carries some information. Researchers with a share of conventionality, but they are already talking about a kind of "memory" of molecules, atoms, elementary particles. Carbon atoms that have been in living beings are "biogenic".

As soon as the matter does not disappear at the moment of the Universe convergence to a point, then the information it carries does not disappear, and the information it carries is indestructible. Our world is filled with it, as it is filled with the matter that makes it up.

The universe that will replace ours, will it be a repetition of it?

Quite possibly, some cosmologists answer.

Not necessarily, others argue. There are no physical justifications, says, for example, Dr. R. Dick from Princeton University, that every time at the moment of the formation of the Universe the physical laws were the same as at the moment of the beginning of our cycle. If these patterns differ even in the most insignificant way, then the stars will not be able to subsequently create heavy elements, including carbon, from which life is built. Cycle after cycle, the universe can come and go without giving birth to a spark of life. This is one of the points of view. It could be called the "discontinuity of being" point of view. It is discontinuous, even if life arises in the new Universe: no threads connect it with the last cycle. According to another point of view, on the contrary, “the Universe remembers its entire prehistory, no matter how far (even infinitely far) it goes into the past.”

Or the concept of biogenesis). In the 19th century, L. Pasteur finally refuted it, proving that the appearance of life where it did not exist is associated with bacteria (pasteurization is getting rid of bacteria). 3. The concept of the current state assumes that the Earth and life on it have always existed, and in an unchanged form. 4. The concept of panspermia connects the appearance of life on Earth with its entry from ...

Galaxies and the Universe. The material systems of the micro-, macro- and mega world differ in size, the nature of the dominant processes and the laws to which they obey. The most important concept of modern natural science lies in the material unity of all systems of the micro-, macro- and mega-world. We can talk about a single material basis for the origin of all material systems at different stages...

Despite the successes of physics in understanding the history of the universe, the reasoning of scientists on this issue can be called a fantasy game, born of modern knowledge, extrapolated to the first moments of the life of the universe. In full, this knowledge cannot be applied to the moment of the birth of the Universe, since it was a super-extreme situation. However, the basic principles we have considered are probably already in place. That is, two trends immediately emerged in the life of the Universe: vacuum breaking(nothing is a perfectly ordered structure) and creation(self-organization) matter.

We don't know what the very first structures in the universe were. Perhaps, in the first moments of the existence of the Universe, such primary structures were realized that have direct analogies with the ideal images used by man in the process of thinking. Therefore, all ancient cosmological concepts depict the creation of the Universe as a free volitional act of a single Creator.

We have already “guessed” that in the course of these processes, already in the first milliseconds, the Universe became electrically inhomogeneous for some reason, conditions arose for the generation of pairs of oppositely charged particles. That is, the Universe at this stage can be represented in the form of a kind of vacuum capacitor, giving birth "out of nothing" pairs of particle-antiparticle. Where did the energy to create these particles come from? There is no consensus on this matter. Any arguments on this topic are only hypotheses. Based on the information model of the Universe, then the concept of energy is reduced to the difference between the entropies of the final (not yet realized, but potentially possible) and initial (realized) states. In other words, energy is the difference between what we could have and what we actually have. It is this difference that generates the driving force that sets in motion the entire evolutionary process in the Universe.

The world of elementary particles was probably very diverse. Our synchrophasotrons quite roughly model the processes of that time. With an increase in the number of particles, the electrical inhomogeneity was smoothed out (the capacitor was discharged). The "birth rate" of particles first slowed down, then stopped. At this stage of the development of the Universe, along with the birth of charges, their death was also present - the annihilation of particles and antiparticles with a complete transition of their structure into field uniform. And so the “birth” stopped, but the annihilation remained. It was the "first ecological catastrophe" known to us. Fortunately, the early universe was somehow asymmetric: there were slightly more electrons than positrons, and more protons than antiprotons. Therefore, for every 100 million pairs, one particle "survived". This was enough to build the entire substance of the Universe, which at that time was a few seconds old.

The era of elementary particles is over. As a result, the Universe "discovered" stable particles, which became elements for building systems of a higher hierarchical level. If this had not happened, and the destruction of elementary particles would have been complete, then the Universe would have reached the maximum of entropy (the Universe filled with radiation) and, possibly, would have ceased to exist (if only because the concepts of space and time are not defined without matter). The "invention" of stable particles increased the maximum possible value of the entropy of the Universe to some value, that is, it became possible to further increase the entropy, but not due to the destruction of particles, but due to their scattering and mixing in different combinations.

This algorithm is then repeated. That is, in in the process of systems striving for a maximum of entropy, they must find stable forms that can push the value itself. Such forms safely bypass the barriers of natural selection. IN natural selection the winner is the one who gives the greatest prospects in terms of the further development of the universe. And since with each step up the hierarchical ladder of the system organization, the number of elements of such systems becomes less and less, then the required increase in the entropy of the Universe can only be ensured by an increase in the complexity of the internal organization of systems (the law of complication of system organization). How harder system, the greater the number of subsystems contained in its structure. In this case, each particle (element) can enter simultaneously into many subsystems. This means that the number of real objects (particles, subsystems, systems, etc.) that are terms of entropy increases, which ensures the increase in the maximum possible value of entropy. We call this process evolution.

The universe expanded and cooled, particles lost energy and condensed into atoms, mostly hydrogen. True, it is believed that helium was also present at the same stage (about 30%). Heavier elements were practically absent, they were formed at later stages of the evolutionary process.

Any inhomogeneities in the density of hydrogen are enhanced by gravitational forces, and the hydrogen-helium cloud breaks up into clumps (protogalaxies). From clusters within galaxies, first-generation stars are born. There is still no complete clarity here. It is possible that stars were born as the protogalaxy contracted.

Another version is also possible, according to which the protogalactic cloud is first compressed to a critical size. Quasars - huge quasi-stellar cosmic bodies, commensurate with the size of the solar system, consisting of matter rotating around the center at great speed, found at the very borders of the observable part of the Universe; that is, we see them as they were billions of years ago. Perhaps it was in quasars that helium was synthesized. Perhaps that is why quasars become unstable and explode, and the first generation stars are formed from the products of the explosion in the process of their scattering due to the gravitational compression of local concentrations. So it was or not, we can only guess, we know very little about quasars.

gas cloud future star compressed by the forces of gravity. Soon this contraction is slowed down by the increasing pressure of the warming interiors of the star, in which thermonuclear fusion reactions begin. Hydrogen turns into helium, and heavier elements are synthesized from helium, which fall to the center of the star. A star is a cauldron in which heavy elements are “boiled”, the structure of matter becomes more complex. This makes the star unstable, and it explodes like a supernova, forming clouds of gas and dust enriched in heavy elements. The central part of the star experiences strong compression, in its place a white dwarf, a neutron star or a black hole is formed if the mass of the star exceeded 50 solar masses. Previously, in our galaxy, stars exploded about once a year, now once every 30 years.

The solar system was born about five billion years ago by the condensation of a gas-dust cloud. Therefore, the Sun is a second-generation star. The sun and planets formed, apparently, simultaneously. As the gas-dust cloud contracts, dust particles collide and coalesce into larger formations (meteorites), from which asteroids are subsequently formed. Closer to the Sun, bodies can form only from heavy and refractory materials. Light substances evaporate and escape to more distant orbits. Therefore, the planets closest to the Sun are more solid. They are formed by the merger of asteroids and the deposition of dust in the orbit of a given planet. Gradually the orbit is cleared. Observations show that the dynamics of the formation of craters on Mercury, Mars and the Moon about 4.6 billion years ago was hundreds of times higher than today. Distant giant planets have a lower density.

The orbits of the planets are close to circles, the diameters of which are subject to the golden section rule (Bode's law). According to Bode's law, there should be another planet between Mars and Jupiter, instead of which an asteroid belt has been discovered. All sorts of fantastic assumptions arose about the death of the planet Phaeton that once existed in this orbit. This is also evidenced by some mythical stories. Scientists believe that this orbit is a natural boundary between small dense planets and giant planets, which gave rise to instability that did not allow either a small planet or a giant planet to form here. The gravitational influence of the neighboring planets, especially the giant planets, dispersed the protoplanetary condensation of the future dense planet too much, scattering the asteroids into more elongated orbits. Therefore, the asteroid belt remained almost in its original form. By the way, this somewhat echoes the legend of Phaeton.

By the time the Earth was formed, the evolution of the Universe had prepared the possibility of the birth of earthly life.
Expanding, the Universe quickly cools down, which leads to the emergence of fractal structures that combine order and randomness, chaos. In fractal structures, complexity is achieved by repeating simpler structures (fractal genes) according to a certain algorithm. Examples of fractal structures are snowflakes, frost patterns on glass, coastlines seas, tree branches, spiral shells, etc. Biosystems are especially typical fractal structures. Usually, fractal structures arise with a relatively rapid loss of energy in an open system, when the elements of the system do not have time to reorganize into symmetrical ordered structures, such as regular crystals, so they retain a share of chaos.
During cooling, the possibility of the stable existence of more and more complex structures appears, which would collapse at higher energies.
As the Universe expands, the forms of organization of matter become more complicated, that is, the complexity of forms is somehow connected with the volume of the Universe.
As long as the universe is expanding, evolution cannot be stopped. It is not known whether the expansion of the Universe is the driving force behind the global evolutionary process, but these two processes are probably closely related to each other.

Models of the stationary Universe. The uniqueness of the Universe does not allow for an experimental verification of the hypotheses put forward and raising them to the level of theories, so the evolution of the Universe can only be considered within the framework of models.

After the creation of classical mechanics, the scientific picture of the world was based on Newton's ideas about space, time and gravity and described a constant in time, i.e. stationary, infinite Universe created by the Creator.

In the XX century. new theoretical foundations have appeared for creating new cosmological models.

First of all, it is necessary to mention the cosmological postulate, according to which the physical laws established in a limited part of the Universe are also valid for the entire Universe. In addition, the homogeneity and isotropy of the large-scale distribution of matter in the Universe is considered an axiom. At the same time, the model of evolution should correspond to the so-called anthropic principle, i.e. provide for the possibility of certain stage evolution of the observer (reasonable person).

Since it is gravitation that determines the interaction of masses at large distances, the theoretical core of cosmology of the twentieth century. became the relativistic theory of gravity and space-time - general theory relativity. According to this theory, the distribution and motion of matter determine the geometric properties of space-time and at the same time depend on them themselves. The gravitational field manifests itself as a "curvature" of space-time. In Einstein's first cosmological model, based on general relativity in 1916, the universe is also stationary. It is boundless, but closed and has finite dimensions. The space closes on itself.

Friedman's models of the non-stationary Universe. Einstein's model of the stationary Universe was refuted in the works of the Russian scientist A.A. Friedman (1888 - 1925), who in 1922 showed that curved space cannot be stationary: it must either expand or contract. Three different models of the change in the radius of curvature of the Universe are possible, depending on the average density of matter in it, and in two of them the Universe expands infinitely, and in the third, the radius of curvature changes periodically (the Universe pulsates).

Although E. Hubble's discovery of the dependence of the galaxy receding rate on the distance to them confirmed the expansion of the Universe, at present, a comparison of the experimentally estimated density of matter with the critical value of this parameter, which determines the transition from expansion to pulsation, does not make it possible to unambiguously choose a scenario for further evolution. These two quantities turned out to be close, and the experimental data were not sufficiently reliable.

The expansion of the Universe is currently a well-founded and generally recognized fact that allows us to estimate the age of the Universe. According to the most common estimates, it is 10 18 s (18 billion years). Therefore, current models suggest a "beginning" of the universe. How did its evolution begin?

hot universe model. At the heart of modern ideas about the initial stages of the evolution of the Universe is the model of the "hot Universe", or "Big Bang", the foundations of which were laid in the 40s of the XX century. Russian scientists working in the USA, G.A. Gammov (1904 - 1968). In the simplest version of this model, it seems that the Universe arose spontaneously as a result of an explosion from a superdense and superhot state with infinite space curvature (singularity state). The "hotness" of the initial singular state is characterized by the predominance of electromagnetic radiation in it over matter. This is confirmed by the experimental discovery in 1965 by American astrophysicists Penzias (b. 1933) and Wilson (b. 1936) of isotropic electromagnetic "relic radiation". Modern physical theories make it possible to describe the evolution of matter starting from the moment of time t= 10 -43 s. The very initial moments of the evolution of the Universe are still behind the physical barrier. Only from the moment t= 10 -10 s after the Big Bang, our understanding of the state of matter in early universe and the processes occurring in it can be verified experimentally and described theoretically.

As the universe expands, the density of matter in it decreases and the temperature drops. At the same time, processes of qualitative transformations of particles of matter take place. At the moment 10 -10 s, matter consists of free quarks, leptons and photons (see Fig. section III). As the Universe cools, the formation of hadrons occurs, then the nuclei of light elements appear - isotopes of hydrogen, helium, lithium. The fusion of helium nuclei stops at the moment t= 3 min. Only after hundreds of thousands of years, the nuclei combine with electrons, and hydrogen and helium atoms arise, and from that moment on, the substance ceases to interact with electromagnetic radiation. "Relic" radiation arose precisely during this period. When the size of the universe was about 100 times smaller than at the present era, gaseous clumps arose from the inhomogeneities of gaseous hydrogen and helium, which fragmented and led to the emergence of stars and galaxies.

The question of the exclusivity of the Universe as an object of cosmology remains open. Along with the widespread point of view that the entire Universe is our Metagalaxy, there is an opposite opinion that the Universe can consist of many metagalaxies, and the idea of the uniqueness of the Universe is historically relative, determined by the level of science and practice.

Cosmology studies the physical nature, structure and evolution of the Universe as a whole.

concept "Universe" means space accessible to human observation.

Cosmology considers the most general properties of the entire region of space covered by observation. We call her Metagalaxy. Our knowledge of the Metagalaxy is limited to the observation horizon. This horizon is determined by the fact that the speed of light is not instantaneous. Consequently, we can observe only those regions of the Universe from which light has managed to reach us by now. In this case, we see objects not in their current state, but in the one in which they were at the time of the emission of light.

Models of the Universe, like any others, are built on the basis of theoretical concepts that currently exist in cosmology, physics, mathematics, chemistry and other related disciplines.

Several prerequisites for studying the Universe:

it is believed that the laws of the functioning of the world formulated by physics operate throughout the universe
it is believed that the observations of astronomers also apply to the entire universe
it is believed that those conclusions are true that do not contradict the existence of man (anthropic principle)

The conclusions of cosmology are called models of the origin and development of the Universe.

The problems of the origin and structure of the Universe have occupied people since antiquity. Despite the high level of astronomical knowledge of the peoples of the ancient East, their views on the structure of the world were limited to direct visual sensations. Therefore, in Babylon there were ideas according to which the Earth looks like a convex island surrounded by an ocean. It is as if there is a "kingdom of the dead" inside the Earth. The sky is a solid dome resting on the earth's surface and separating the "lower waters" (the ocean flowing around the earth's island) from the "upper" (rain) waters. Celestial bodies are attached to this dome, as if the gods live above the sky. According to the ideas of the ancient Egyptians, the Universe looks like a large valley, elongated from north to south, in the center of which is Egypt. The sky was likened to a large iron roof, which is supported on pillars, on which stars are suspended in the form of lamps.

In ancient China, there was an idea according to which the Earth has the shape of a flat rectangle, above which a round, convex sky is supported on pillars. The enraged dragon seemed to bend the central pillar, as a result of which the Earth leaned towards the east. Therefore, all rivers in China flow to the east. The sky tilted to the west, so all the heavenly bodies move from east to west.

In the Greek colonies on the western shores of Asia Minor (Ionia), in southern Italy and in Sicily, in the seventh century BC, science began to develop rapidly, in particular, philosophy, as a doctrine of nature. It is here that simple contemplation of natural phenomena and their naive interpretation are replaced by attempts to scientifically explain these phenomena, to unravel their true causes. One of the most important ancient Greek thinkers was Heraclitus of Ephesus. It is to him that the words belong: "The world, one of everything, was not created by any of the gods and by any of the people, but was, is and will be an ever-living fire, naturally ignited and naturally extinguished ..." Then Pythagoras of Samos expressed the idea that the Earth, like other celestial bodies, has the shape of a ball. The Universe was presented to Pythagoras in the form of concentric, nested transparent crystal spheres, to which the planets seemed to be attached.

Heraclid Pontus and Eudoxus of Cnidus in the 4th century BC. argued that all bodies in the Universe rotate around their axis, and revolve around a common center (Earth) in spheres, the number of which in different cosmogony varied from 30 to 55. The top of this picture of the world was the system Claudius Ptolemy(II century AD).

The first scientifically based models of the Universe appeared after the discoveries of Copernicus, Galileo and Newton. First, R. Descartes put forward the idea of an evolutionary vortex Universe. According to his theory, all space objects were formed from primary homogeneous matter as a result of vortex movements. The solar system, according to Descartes, is one of the whirlwinds of cosmic matter. I. Kant developed the idea of an infinite Universe, formed under the action of mechanical forces of attraction and repulsion, and tried to find out the further fate of such a Universe. The great French mathematician Laplace described Kant's hypothesis mathematically.

Gravitational Paradox: according to the Newtonian concept of gravity, an infinite Cosmos with a finite mass density must give an infinite force of attraction. Infinitely increasing gravitation inevitably leads to infinite accelerations and infinite speeds of cosmic bodies. Therefore, the speed of the bodies must increase with increasing distance between the bodies. But this does not happen, and then it turns out that the Universe cannot exist forever.

Photometric paradox (Olbers paradox): with an infinite universe filled with an infinite number of stars, the sky should be uniformly bright. In fact, no such effect is observed. In 1823, Olbers showed that dust clouds that absorb the light of more distant stars heat up themselves and must therefore emit light. This paradox resolved itself after the creation of a model of the expanding universe.

When Einstein was working on his general theory of relativity, scientists didn't see the universe as it is now. The Metagalaxy and its expansion had not yet been discovered, so Einstein relied on the idea of a stationary Universe, which is evenly filled with galaxies located at constant distances. Then inevitably followed the conclusion about the compression of the world under the influence of gravity. This result was in conflict with the conclusions of general relativity. In order not to conflict with the generally accepted picture of the world, Einstein arbitrarily introduced a new parameter into his equations - cosmic repulsion, which was characterized by the cosmological constant. A. Einstein assumed that the Universe is stationary, infinite, but not unlimited. That is, it was conceived as a sphere, constantly increasing in volume, but having boundaries.

The only person who in 1922 believed in the correctness of the conclusions of general relativity as applied to cosmological problems was the young Soviet physicist A. A. Fridman. He noticed that the non-stationarity of the curvature of space follows from the theory of relativity.

Friedman's model is based on ideas about isotropic, homogeneous and non-stationary state of the Universe.

Isotropy indicates that there are no distinguished points of directions in the Universe, that is, its properties do not depend on the direction.

Uniformity The universe characterizes the distribution of matter in it. This uniform distribution of matter can be substantiated by counting the number of galaxies up to a given apparent magnitude. According to observations, the density of matter in the part of space that we see is on average the same.

non-stationarity means that the universe cannot be in a static, unchanging state, but must either expand or contract

In modern cosmology, these three statements are called cosmological postulates. The totality of these postulates is the fundamental cosmological principle. The cosmological principle follows directly from the postulates of the general theory of relativity.

A. Friedman, on the basis of the postulates put forward by him, created a model of the structure of the Universe, in which all galaxies move away from each other. This model is similar to a uniformly inflated rubber ball, all points of space of which are moving away from each other. The distance between any two points increases, but none of them can be called the center of expansion. Moreover, the greater the distance between the points, the faster they move away from each other.

Initially, these hypotheses were perceived as an incident, including by A. Einstein. However, already in 1926 an epoch-making event in cosmology took place, which confirmed the correctness of the calculations of Friedmann - De Sitter - Lemaitre. Such an event that influenced the construction of all existing models of the Universe was the work of the American astronomer Edwin P. Hubble. In 1929, while conducting observations on the largest telescope at that time, he found that the light coming to the Earth from distant galaxies is shifted towards the long-wavelength part of the spectrum. This phenomenon, called "Redshift effect" is based on the principle discovered by the famous physicist K. Doppler. The Doppler effect indicates that in the spectrum of a radiation source approaching the observer, the spectral lines are shifted to the short-wave (violet) side, in the spectrum of a source moving away from the observer, the spectral lines are shifted to the red (long-wave) side.

The redshift effect indicates the distance of galaxies from the observer. With the exception of the famous Andromeda Nebula and a few star systems closest to us, all other galaxies are moving away from us. Moreover, it turned out that the speed of expansion of galaxies is not the same in different parts of the Universe. They move away from us the faster, the farther they are located. In other words, the redshift value turned out to be proportional to the distance to the radiation source- this is the strict formulation of Hubble's open law. The regular relationship between the removal rate of galaxies and the distance to them is described using the Hubble constant ( H , km/sec per 1 distance).

V = HR , where V is the removal rate of galaxies, r - the distance between them.

The value of this constant has not yet been definitively established. Various scientists define it in the range of 80 ± 17 km / s for each megaparsec of distance.

The phenomenon of redshift was explained in the phenomenon "recession of galaxies". In this regard, the problems of studying the expansion of the Universe and determining its age from the duration of this expansion come to the fore.

According to all three models of the evolution of the Universe, it had a reference point - a state characterized by a zero moment in time. The initial state of matter in it was some superdense state, which was characterized by instability, which led to its destruction. As a result, the matter of the universe began to rapidly scatter. We now know that for every billion years of life, the Universe expands by 5-10%. The most probable value of the Hubble constant of 80 km/sec gives us values for the expansion time, from 13 to 17 billion years. In 2002, using a computer model of the current state of the Universe, results were obtained that give us its lifetime in 13.7 Ga.

The mechanism of further evolution depends on the average density of matter in it. The critical density of a substance corresponds to a value of 3 hydrogen atoms in 1 m3 of space. However, the uncertainty in the modern value of the matter density of the Universe is very large. If we sum up the masses of all currently known Galaxies and interstellar gas, then we get the value ρ = 0.3 of the H atom, that is, an order of magnitude less than the critical one. Accordingly, the universe can expand forever.

Neutrinos, particles formed in the early stages of the development of the universe, can claim the role of carriers of the hidden mass. As it became known in the last 3 years, neutrinos do have mass, therefore, they can participate in the formation of gravitational interactions.

Candidates for the same role are some exotic objects, such as black holes - objects of point size and huge mass, which are contained in the universe in large quantities, spatial string objects, etc.

A very important problem of modern cosmology is the initial moments of the existence of our Universe. A successful attempt to solve this problem is associated with the name of an American astrophysicist Georgy Antonovich Gamow, who in 1942 proposed the concept of the evolution of the universe through the "Big Bang". The main goal of the author of the concept was to, by considering nuclear reactions at the beginning of the cosmological expansion, to obtain the ratios observed in our time between the number of various chemical elements and their isotopes. The theory of the Hot Universe and the Big Bang gives certain predictions about the state of matter in the Universe in the first moments of its life.

At the initial moment of time, the Universe was concentrated in a minimum volume, which was billions of times smaller than a pinhead. And if you follow the mathematical calculations exactly, then at the beginning of the expansion, the radius of the Universe was completely equal to zero, and its density was equal to infinity. This initial state is called singularity is a point volume with infinite density. The known laws of physics do not work in the singularity. It is estimated that this occurred from 13.7 billion years ago.

In a state of singularity, the curvature of space and time becomes infinite, these concepts themselves lose their meaning. There is not just a closure of the space-time continuum, as follows from the general theory of relativity, but its complete destruction

The reasons for the emergence of such an initial state, as well as the nature of the stay of matter in this state, are considered unknown and beyond the competence of any modern physical theory. It is also unknown what happened before the explosion. For a long time, nothing could be said about the causes of the Big Bang and the transition to the expansion of the Universe, but today some hypotheses have appeared that attempt to explain these processes.

So, the initial state before the "beginning" has properties that are beyond the scope of today's scientific ideas. Everything that is familiar to us was violated in it: the forms of matter, the laws governing their behavior, the space-time continuum. Such a state can be called chaos, from which, in the subsequent development of the system, step by step was formed order. Chaos turned out to be unstable, this served as the initial impetus for the subsequent development of the Universe.

The extreme conditions of the "beginning", when even space-time was deformed, suggest that the vacuum was also in a special state, which was called "false" vacuum. This state is characterized by an energy of extremely high density, which corresponds to an extremely high density of matter. In this state of matter, strong stresses can arise in it, which are equivalent to the gravitational repulsion of such a force that caused an unrestrained and rapid expansion. This was the first push - the beginning. With the beginning of the rapid expansion of the universe, time and space arise.

According to the hypothesis of Alan Guth, an American mathematician, in the first moments of time, the universe expanded at an ever-increasing rate. This extension is called inflation. According to various estimates, the inflation period takes an unimaginably short period of time - up to 10-39 seconds after the start. This period is called inflationary. During this time, the Universe had time to swell up to a giant “bubble”, the radius of which was several orders of magnitude greater than the radius of the modern Universe, but there were practically no particles of matter there. By the end of the inflation phase, the universe was empty and cold. Moreover, local inhomogeneities formed in it, which then smoothed out with further expansion of the Universe. Then the balance of forces that kept the Universe in such an unstable state was disturbed, and there was a surge of energy contained in a "false" vacuum. When this vacuum state collapsed, its energy was released in the form of radiation, which heated the Universe to 1027° K. From that moment on, the Universe evolved according to the Hot Big Bang theory.

At ultrahigh temperatures and densities, even the general theory of relativity is not yet applicable, since it does not take into account the quantum effects that prevail at that moment. Possibly, during this period, quanta of the gravitational field, gravitons, could arise.

At this stage, it is possible that mutual transformations of particles and radiation quanta took place. That is, radiation and matter are still inseparable from each other. All three types of interaction - strong, weak and electromagnetic - do not yet differ and are different forms of a single interaction. Physicists call this phase ERA OF GRAND UNIFICATION.

From two quanta of gamma radiation, electron-positron pairs arise.

This is the currently well known process:

g + g ó e + + e -

When the temperature dropped somewhat, the electron-positron pairs began to annihilate. During the annihilation of each such pair, two high-energy photons are released, that is, gamma rays. They have great penetrating power.

The greater the quantum energy, the more massive particles can be formed as a result of interaction.

According to modern physical theory, unique conditions must have existed in the early universe that favored the emergence of quarks And antiquark in - these primary building blocks of the Universe. At that moment, quarks could either be in a free state or exist in the form of quark-gluon jets.

At times less than a millisecond, the temperature was so high that strong interactions dominated. As a result, heavy particles of the hadron class were formed from quarks - mesons And antimesons, protons And antiprotons and some exotic species nuclear particles such as hyperons. The process of the birth of nuclear particles had a the highest degree stabilizing action. The initial anisotropy quickly smoothed out, as a result the Universe became isotropic and filled with radiation.

With a decrease in temperature, a few microseconds after the big bang, the pairs of hadrons, heavy elementary particles, almost completely annihilated. The hadron era, when strong interactions dominated, has ended.

Then came the period of weak interactions. As a result of weak interactions, there was a radioactive decay of free neutrons remaining after the hadron era into electrons and protons, and mesons into muons and antineutrinos.

n° → p + + ē + v

p + + ē → n° + νˉ

It is at this time that education takes place. neutrino And antineutrino. These particles belong to the class of leptons, respectively, the lepton era has begun in the Universe. In the lepton era, the universe is made up of photons, neutrinos, and antineutrinos. H After 0.2 seconds after the singularity, the neutrino is separated from the matter. These particles scatter with great speed throughout the space of the Universe.

For a short period at the beginning of an era, electron-positron pairs are also present. One second after the Big Bang, conditions change. The temperature drops below 10 billion K, and the electron-positron pairs annihilate. Neutron production reactions stop. During this period, there is one neutron for every six protons in the Universe (this ratio has been preserved in the Universe to the present day).

Then events occur in which the neutron actively participates. The process of synthesis is underway heavy elements from the lighter ones. This process is called thermonuclear fusion.

When the temperature of the universe has dropped to 1 billion K. fusion reactions begin.

At this temperature, the energy of protons and neutrons is no longer enough to resist the strong nuclear interaction. They start to connect with each other. First, a neutron is captured by a proton and a deuterium nucleus is formed. Deuterium readily absorbs neutrons. At the next stage, tritium is formed, and, finally, tritium reacts with a proton and a helium nucleus is formed. Almost all neutrons are bound into helium nuclei. As a result of thermonuclear fusion, 25% by mass of helium was formed in the Universe, the rest of the matter consisted of free protons. The big bang created helium. Such a ratio of hydrogen and helium in the Universe (75% : 25%) could be formed only under the conditions in question. Any changes in conditions will lead to a different ratio of these elements in the Universe. Then the temperature dropped and further fusion of heavier nuclei ceased. A very small number of lithium and beryllium nuclei were formed.

A few hours after the Big Bang, the formation of nuclei ceased. During this period, all matter is in the form of plasma - a kind of intermediate state. After 10,000 years, it cooled down to about 3 thousand K, protons (hydrogen nuclei) and nuclei of helium atoms could already easily capture free electrons and turn into neutral atoms of these elements. The plasma has become neutral. At that moment, the radiation separated from the atomic substance and formed what is now called cosmic microwave background radiation. It comes now from all points of the firmament and is not associated with any particular source. It was this fact that served as one of the arguments confirming that there was a Big Bang. This period is called period of separation of matter from radiation.

Since neutral matter interacts with radiation much weaker than fully ionized matter, the length of the path of quanta of this "relic" (residual) radiation exceeded the dimensions of the Universe. Starting from the "epoch of recombination", relic radiation and matter evolve independently. The Doppler effect in the expanding Universe leads to a decrease in the observed frequency of the cosmic microwave background radiation and, accordingly, in the temperature that determines the shape of its spectrum. At present, the temperature of the relict radiation is 2.7 K and it is observed in the form of radio waves in the centimeter and millimeter ranges. It must be emphasized that relic radiation is the only direct source of information about the structure of the Universe in the era of recombination, 10 - 12 billion years ago.

In the next 300 thousand years, the expansion of the Universe took place without any significant changes in its composition and properties. The conclusion about the quiet phase of the expansion of the Universe follows from its current homogeneous and isotropic state.

As the universe expanded, the background radiation passed through the entire spectrum, going from gamma radiation to x-rays, then to ultraviolet, optical, infrared. Finally, the energy of the photons dropped to a value corresponding to the range of radio waves. At any given time, the radiation spectrum was determined by the temperature of the universe. The nature of the radiation in the Universe did not change, gradually shifting towards a lower temperature.

The most important result of this period was that all the electrons were bound, and the Universe became transparent. From that moment on, photons could move straight ahead without being scattered.

After a period of separation of matter from radiation, matter cools rather rapidly compared to radiation. According to the laws of thermodynamics, when a gas expands, the rate of temperature decrease is twice the rate of expansion. The radiation temperature, in turn, decreases with the expansion of the system only linearly. In this case, photons lose less energy during expansion than slowly moving particles. In the modern Universe, the remaining matter has practically lost all its temperature, which is only 3 ° K.

During the period when the temperature reached values at the level of 3000°K, it became possible to synthesize heavier elements in the Universe.

By virtue of the principle of uncertainty, random densifications of matter, the so-called density fluctuations, arise and develop in the expanding Universe. Modern physical science cannot find sufficiently reasonable explanations for the appearance of such fluctuations. All assumptions are preliminary and need to be clarified. One of the assumptions is based on the participation of neutrinos in this process.

While the neutrinos were moving at a speed close to C, their fluctuations quickly dissipated. However, after hundreds of thousands of years, their speed should greatly slow down. Starting from a certain moment, large concentrations of neutrinos no longer dissipate, and give rise to the first structural formation of the Universe. These formations are composed of matter, and neutrinos play the role of centers of gravity for these giant concentrations.

In the expanding Universe, the emergence of these regions leads to the gradual development of slowly changing perturbations. These densifications arose during the separation of matter from radiation. Gradually, the seals increased and gravitational interactions developed inside them. As a result, these regions stop expanding and collapse, resulting in the formation of protogalaxies. The appearance of such densifications was the beginning of the birth of large-scale structures in the Universe. According to calculations, simple formations resembling pancakes should have arisen from these condensations.

The compression of hydrogen-helium plasma into "pancakes" inevitably led to a significant increase in their temperature. As the Universe expanded, the contraction of the big “pancake” also gave rise to its instability, and it broke up into smaller subsystems that became the embryos of galaxies. The critical mass at which these processes took place was 100 billion solar masses, the extent of the cloud was 150,000 light years.

After compression, the protogalactic cloud could no longer remain uniform and spherically symmetrical. Gravity in it prevails over pressure forces. The speed of compression of matter in the cloud was much higher than the speed of sound. With such a compression of the gas cloud, turbulent flows are inevitably generated. Small inhomogeneities grow in the composition of a large cloud. A process of gas fragmentation randomly distributed throughout the volume occurs. The result of this process is the formation of fragments the size of currently existing galaxies. The galaxies are fairly close in size, averaging around 30,000 light-years. Only irregular galaxies turn out to be somewhat smaller than usual ones.

Under conditions of cloud formation at high temperatures, the radiation freely leaves it, and it begins to cool. The rapid cooling of the fragment contributes to its further fragmentation, in which primary stars begin to form. Coming STAR FORMATION PHASE.

The resulting galaxies are not randomly distributed in the space of the Universe. The nature of their distribution is called the correlation of galaxies. Galaxies are first formed from a protogalactic cloud, and then gradually crowd together. The hierarchy of structure formation includes groups of galaxies inside poor clusters, which then enter into rich clusters. Probably, their initial spread was random. Then gravitational forces came into play, which led to the contraction of galaxies into large clusters.

It seems interesting to trace the structure of the part of the Universe that we see - the Metagalaxy. The metagalaxy consists of giant star systems like ours - galaxies. Only three such objects are visible in the sky with the naked eye, as faintly luminous blurry spots - these are the Large and Small Magellanic Clouds (in the southern hemisphere) and the Andromeda Nebula. Many millions of other galaxies can only be seen with powerful telescopes. Several hundred galaxies are well studied. For several thousand, the spectrum was obtained and the scattering determined; for several tens of thousands, estimates of the magnitude and angular distance, features of appearance are described. All galaxies are classified and placed in catalogs under the appropriate designations. So, for example, the Andromeda Nebula was named M31.

E. Hubble dealt with the problem of studying galaxies and their classification. By appearance and the nature of the distribution of brightness, he divided all galaxies into elliptical, spiral, lenticular and irregular.

Elliptical - have in space the shape of ellipsoids with varying degrees of compression. Some of them have an almost perfect spherical shape (Figure 1. E0-E4), and some are strongly flattened and look like a lens. These are lenticular galaxies (Fig. 1. E5 - E7). They do not have a core, their brightness gradually increases from the periphery to the center. There is no internal structure. Almost all of them have a predominance of red in the spectrum.

spiral galaxies(S0 - Sc - Svs) - the most common. A typical representative is our galaxy. Unlike elliptical ones, they have a central core and a structure in the form of spiral arms. The substance in them is present not only in the spiral branches, but also between them. The arms contain the brightest hot stars, young star clusters, and luminous gaseous nebulae. They all have a central stellar disk, a spheroidal component similar to a small lenticular galaxy, and a flat component or arms.

Irregular galaxies are asymmetrical, contain hot stars, young stellar formations, and large amounts of interstellar gas. These are the galaxies closest to us, the Magellanic Clouds. It is in galaxies of this type that interesting celestial phenomena are found - supernova explosions, etc.

All galaxies are dispersed in the Metagalaxy not by chance, but are located at the nodes of an irregular network, reminiscent of the honeycombs of a bee hive. There are practically no galaxies between these nodes.

Galaxies - this system of stars and their associated interstellar media - a rarefied gas with a small admixture of solid dust grains. The diameters of galaxies are 50-70 or more kiloparsecs. There are also dwarf systems, the sizes of which are an order of magnitude smaller. All galaxies have fairly intense radio emission.

In outer space, there are galaxies with anomalous properties.

Radio galaxies. They are among the massive elliptical galaxies and are distinguished by anomalously high radio emission - tens of thousands of times higher than that of normal ones. The radiation mechanism is associated with the ejection of large clouds of particles moving in a magnetic field. One of these galaxies is located in the constellation Centaurus. In total, about 500 such objects have been discovered.

Quasars. In 1963, powerful sources of radio emission were discovered, which were called quasi-stellar, or quasars. The power of their release of energy is hundreds and thousands of times greater than that of ordinary galaxies. About 1500 such objects are known. A number of features of quasars connect them with the nuclei of galaxies - compactness, variability of radiation, non-thermal nature of the spectrum. Feature spectra - in them the redshift reaches its maximum size. These are probably the most distant objects from us, flying at a speed close to C.

The quasar belt is located at a distance of 600 megaparsecs from the Milky Way. Further and closer, they are practically absent. Probably, their formation was timed to a certain period in the development of the Universe. These are the nuclei of galaxies that are at some stage of their evolution.

The current state of the universe is still very poorly understood. However, there probably already exists an answer to the question: What is the current shape of the universe?

Long-term observations have shown that the Universe has a number of physical properties that drastically reduce the number of possible contenders for its shape. And one of the main such properties of the topology of the Universe is its curvature. According to the current concept, about 300,000 years after the Big Bang, the temperature of the universe dropped to a level sufficient to combine electrons and protons into the first atoms. When this happened, radiation that was initially scattered by charged particles suddenly became able to pass unhindered through the expanding universe . This radiation, now known as the cosmic microwave background, or cosmic microwave background, is surprisingly homogeneous and reveals only very slight deviations (fluctuations) in intensity from the mean value. Such homogeneity can only exist in the Universe, the curvature of which is constant everywhere..

The constancy of curvature means that the space of the Universe has one of three possible geometries: flat Euclidean spherical with positive curvature or hyperbolic with negative.

The German mathematician Carl Friedrich Gauss, back in the first half of the 19th century, set out to answer the question: are the trajectories of light rays passing over the spherical space of the Earth curved? It turned out that on a small (by astronomical standards) scales, the Universe appears as Euclidean. Recent studies conducted with high-altitude balloons raised over Antarctica also support this conclusion. When measuring the angular power spectrum of the CMB, a peak was registered, which, as the researchers believe, can only be explained by the existence of cold black matter - relatively large, slowly moving objects - precisely in the Euclidean Universe. That is, scientists say quite confidently that the space of our Universe should be satisfactorily described by Euclid's geometry, as three-dimensional space very small curvature

Until recently, theorists considered all possible options for the further evolution of the Universe: infinite expansion, contraction, and a stationary state.

The conclusion that our universe will expand forever at an ever-increasing rate has been recognized as the most important scientific discovery in astronomy in the last 3 years.

Two groups of astronomers, carefully examining the light that comes to us from the most distant stars, came to the conclusion that the matter in the universe is flying apart faster and faster. Moreover, this expansion will continue forever. American astronomers from the universities of Washington, Seattle and the Berkeley National Laboratory in California took part in the work. Later, their result was confirmed by other groups. For the first time in the entire past century, a clear statement was made about the scenario for the development of the Universe on an experimental basis. The result obtained revives the very popular idea at the beginning of the century (actively refuted by Albert Einstein) that there is a repulsive force between masses of matter, working against gravitational force attraction. The presence of such a force could help explain the open expansion of the universe.

What will happen to such a universe in the future? As space expands, matter becomes more and more rarefied, galaxies and their clusters move away from each other, and the temperature of the background radiation approaches absolute zero. Over time, all stars will complete their life cycle and become either white dwarfs or neutron stars or into black holes. The era of luminous matter will end and the universe will go out. will come heat death of the universe predicted by Clausius and Helmholtz back in the middle of the 19th century.

According to the theory developed by the English astrophysicist S. Hawking, black holes will absorb the remaining matter of the universe. They themselves will slowly evaporate, releasing a stream of elementary particles into space. In 10 66 years they will begin to explode, throwing out a stream of particles, antiparticles and radiation into space. Particles annihilate with antiparticles, and the radiation is evenly scattered in space. It will be a completely disordered state with a maximum level of entropy.