in natural science

Topic: Modern science of the origin of the Universe.

Completed student

Of the course

_______________________

Teacher:

_______________________

_______________________

PLAN A:

Introduction 3

Pre-scientific consideration of the origin of the universe. 5

Theories of the twentieth century about the origin of the universe. eight

Modern science about the origin of the universe. 12

Used literature: 18

Throughout his existence, Man studies the world around him. Being a thinking being, Man, both in the distant past and now, could not and cannot be limited to what is directly given to him at the level of his daily practical activity, and has always strived and will strive to go beyond its limits.

It is characteristic that man's cognition of the world around him began with cosmogonic reflections. It was then, at the dawn of mental activity, that the thought of "the beginning of all beginnings" arose. History does not know a single people who, sooner or later, in one form or another, did not ask this question and would not try to answer it. The answers, of course, were different, depending on the level of spiritual development of a given nation. The development of human thought, scientific and technological progress made it possible to advance in resolving the question of the origin of the Universe from mythological thinking to the construction of scientific theories.

The problem of the "beginning of the world" is one of those few ideological problems that run through the entire intellectual history of mankind. Having appeared once into the world, the idea of ​​the "beginning of the world" has always occupied the thoughts of scientists since then and from time to time in one form or another again and again pops up to the surface. So, seemingly forever buried in the Middle Ages, it unexpectedly appeared on the horizon of scientific thought in the second half of the twentieth century and began to be seriously discussed on the pages of special magazines and at meetings of problematic symposia.

Over the past century, the science of the Universe has reached the highest levels of the structural organization of matter - galaxies, their clusters and superclusters. Modern cosmology has actively taken up the problem of the origin (formation) of these cosmic formations.

How did our distant ancestors imagine the formation of the Universe? How does modern science explain the origin of the universe? This article is devoted to the consideration of these and other issues related to the emergence of the Universe.

Where did it all come from? How did everything cosmic become the way it appears before humanity? What were the initial conditions that laid the foundation for the observable universe?

The answer to these questions changed with the development of human thought. Among the ancient peoples, the origin of the Universe was endowed with a mythological form, the essence of which boils down to one thing - a certain deity created the entire world around Man. In accordance with the ancient Iranian mythopoetic cosmogony, the Universe is the result of the activity of two equivalent and interconnected creative principles - the God of Good - Ahuramazda and the God of Evil - Ahriman. According to one of her texts, the primordial cosmos was the primordial existence, the separation of which led to the formation of parts of the visible Universe. The mythological form of the origin of the Universe is inherent in all existing religions.

Many outstanding thinkers far from us historical eras tried to explain the origin, structure and existence of the universe. They deserve special respect for their attempts to comprehend the essence of the Universe, in the absence of modern technical means, using only their minds and the simplest devices. If you make a small excursion into the past, you will find that the idea of ​​an evolving Universe, adopted by modern scientific thought, was advanced by the ancient thinker Anaxagoras (500-428 BC). Also noteworthy are the cosmology of Aristotle (384-332 BC), and the works of the outstanding thinker of the East Ibn Sina (Avicenna) (980-1037), who tried to logically refute the divine creation of the world, and other names that have come down to our time.

Human thought does not stand still. Along with the change in the idea of ​​the structure of the Universe, the idea of ​​its origin also changed, although in the conditions of the existing strong ideological power of religion, this was associated with a certain danger. Maybe this explains the fact that the natural science of the modern European time avoided discussing the question of the origin of the Universe and focused on studying the structure of the Near Space. This scientific tradition for a long time determined the general direction and the very methodology of astronomical, and then astrophysical research. As a result, the foundations of scientific cosmogony were laid not by natural scientists, but by the philisophists.

Descartes was the first to take this path, who tried to theoretically reproduce "the origin of the luminaries, the Earth and the entire visible world, as it were, from some seeds" and to give a single mechanical explanation of the entire set of astronomical, physical and biological phenomena known to him. However, Descartes's ideas were far from the science of his day.

Therefore, it would be fairer to start the history of scientific cosmogony not with Descartes, but with Kant, who painted a picture of the "mechanical origin of the entire universe." It is Kant who owns the first scientific-cosmogonic hypothesis about the natural mechanism of the emergence of the material world. In the limitless space of the universe, recreated by the creative imagination of Kant, the existence of countless other solar systems and other milky ways is as natural as continuing education new worlds and the death of old ones. It is with Kant that the conscious and practical combination of the principle of universal connection and unity of the material world begins. The universe has ceased to be an aggregate of divine bodies, perfect and eternal. Now the world harmony of a completely different kind appeared before the amazed human mind - the natural harmony of systems of interacting and evolving astronomical bodies, interconnected as links of one chain of nature. However, it is necessary to note two characteristic features of the further development of scientific cosmogony. The first of them is that the post-Kantian cosmogony limited itself to the limits of the solar system and until the middle of the twentieth century it was only about the origin of the planets, while the stars and their systems remained beyond the horizon of theoretical analysis. The second feature is that the limited observational data, the uncertainty of the available astronomical information, the impossibility of experimental substantiation of cosmogonic hypotheses ultimately led to the transformation of scientific cosmogony into a system of abstract ideas, divorced not only from other branches of natural science, but also from related branches of astronomy.

The next stage in the development of cosmology dates back to the twentieth century, when the Soviet scientist A.A. Fridman (1888-1925) mathematically proved the idea of ​​a self-developing universe. The work of A.A. Fridman radically changed the foundations of the previous scientific worldview. According to him, the cosmological initial conditions for the formation of the Universe were singular. Explaining the nature of the evolution of the Universe, expanding starting from a singular state, Friedman highlighted two cases:

a) the radius of curvature of the Universe is constantly increasing over time, starting from zero;

b) the radius of curvature changes periodically: the Universe is compressed into a point (into nothing, a singular state), then again from a point, brings its radius to a certain value, then again, decreasing the radius of its curvature, turns into a point, etc.

In a purely mathematical sense, the singular state appears as nothing - a geometric entity of zero size. On the physical plane, the singularity appears as a very peculiar state in which the density of matter and the curvature of space-time are infinite. All super-hot, super-curved and super-dense cosmic matter is literally pulled into a point and can, in the figurative expression of the American physicist J. Wheeler, "squeeze through the eye of a needle."

Passing on to the assessment of the modern view of the singular origin of the Universe, it is necessary to pay attention to the following important features of the problem under consideration as a whole.

First, the concept of an initial singularity has a fairly specific physical content, which, as science develops, is more and more detailed and refined. In this respect, it should be considered not as a conceptual fixation of the absolute beginning of "all things and events", but as the beginning of the evolution of that fragment of cosmic matter, which at the modern level of development of natural science has become an object of scientific knowledge.

Secondly, if, according to modern cosmological data, the evolution of the Universe began 15-20 billion years ago, this does not mean at all that the Universe had not existed before or was in a state of eternal stagnation.

Achievements of science expanded the possibilities in the knowledge of the world around Man. New attempts were made to explain how it all began. Georges Lemaitre was the first to raise the question of the origin of the observed large-scale structure of the Universe. He put forward the concept of the "Big Bang" of the so-called "primitive atom" and the subsequent transformation of its fragments into stars and galaxies. Of course, from the height of modern astrophysical knowledge, this concept represents only historical interest, but the very idea of ​​the initial explosive movement of cosmic matter and its subsequent evolutionary development has become an integral part of the modern scientific picture of the world.

A fundamentally new stage in the development of modern evolutionary cosmology is associated with the name of the American physicist G.A. Gamow (1904-1968), thanks to which the concept of a hot universe entered science. According to his proposed model of the "beginning" of the evolving Universe, the "primordial atom" of Lemaitre consisted of highly compressed neutrons, the density of which reached a monstrous value - one cubic centimeter of primary matter weighed a billion tons. As a result of the explosion of this "first atom", according to G.A. Gamov, a kind of cosmological cauldron with a temperature of the order of three billion degrees was formed, where natural synthesis took place. chemical elements... Fragments of the primary egg - individual neutrons then disintegrated into electrons and protons, which, in turn, combined with non-decayed neutrons, formed the nuclei of future atoms. All this happened in the first 30 minutes after the "Big Bang".

The hot model was a concrete astrophysical hypothesis that indicated the way to experimentally test its consequences. Gamow predicted the existence of the remnants of thermal radiation from the primary hot plasma at the present time, and his colleagues Alfer and Herman, back in 1948, quite accurately calculated the temperature of this residual radiation of the modern Universe. However, Gamow and his collaborators failed to give a satisfactory explanation of the natural formation and prevalence of heavy chemical elements in the Universe, which was the reason for the skepticism of his theory on the part of specialists. As it turned out, the proposed mechanism of nuclear fusion could not ensure the emergence of the currently observed amount of these elements.

Scientists began to look for other physical models of the "beginning". In 1961, Academician Ya B Zeldovich put forward an alternative cold model, according to which the initial plasma consisted of a mixture of cold (with temperatures below absolute zero) degenerate particles - protons, electrons and neutrinos. Three years later, astrophysicists I.D. Novikov and A.G. Doroshkevich produced comparative analysis two opposite models of cosmological initial conditions- hot and cold - and indicated the path of experimental verification and selection of one of them. It was proposed to try to detect the remnants of the primary radiation by studying the spectrum of radiation from stars and cosmic radio sources. The discovery of the remnants of the primary radiation would confirm the correctness of the hot model, and if they do not exist, then this will testify in favor of the cold model.

At almost the same time, a group of American researchers led by physicist Robert Dicke, not knowing about the published results of the work of Gamow, Alfer and Hermann, revived the hot model of the Universe based on other theoretical considerations. By means of astrophysical measurements, R. Dicke and his colleagues found confirmation of the existence of cosmic thermal radiation. This epoch-making discovery made it possible to obtain important, previously inaccessible information about the initial stages of the evolution of the astronomical universe. The recorded relic radiation is nothing more than a direct radio report about the unique universal events that took place shortly after the "Big Bang" - the most grandiose in its scale and consequences of a catastrophic process in the foreseeable history of the Universe.

Thus, as a result of recent astronomical observations, it was possible to unambiguously resolve the fundamental question of the nature of the physical conditions that prevailed at the early stages of cosmic evolution: the hot model of the "beginning" turned out to be the most adequate. The foregoing, however, does not mean that all theoretical statements and conclusions of Gamow's cosmological concept have been confirmed. Of the two initial hypotheses of the theory - about the neutron composition of the "cosmic egg" and the hot state of the young Universe - only the last one has stood the test of time, indicating the quantitative predominance of radiation over matter at the origins of the currently observed cosmological expansion.

At the current stage of the development of physical cosmology, the task of creating the thermal history of the Universe, in particular the scenario of the formation of a large-scale structure of the Universe, has come to the fore.

The last theoretical research of physicists was carried out in the direction of the following fundamental idea: the basis of all known types of physical interactions is one universal interaction; electro-magnetic, weak, strong and gravitational interactions are different facets of a single interaction, splitting as the energy level of the corresponding physical processes decreases. In other words, at very high temperatures (exceeding certain critical values) different types physical interactions begin to unite, and at the limit, all four types of interaction are reduced to a single single proto-interaction, called the "Great Synthesis".

According to quantum theory, what remains after removing particles of matter (for example, from a closed vessel using a vacuum pump) is not at all empty in the literal sense of the word, as classical physics believed. Although the vacuum does not contain ordinary particles, it is saturated with "half-alive", the so-called virtual bodies. To turn them into real particles of matter, it is enough to excite a vacuum, for example, to act on it with an electromagnetic field created by charged particles introduced into it.

But what was the cause of the "Big Bang"? Judging by the astronomical data, the physical value of the cosmological constant appearing in Einstein's equations of gravitation is very small, possibly close to zero. But even being so insignificant, it can have very large cosmological consequences. The development of quantum field theory has led to even more interesting conclusions. It turned out that the cosmological constant is a function of energy, in particular, it depends on temperature. At ultra-high temperatures that prevailed in the earliest phases of the development of cosmic matter, the cosmological constant could be very large, and most importantly, positive in sign. In other words, in the distant past, the vacuum could be in an extremely unusual physical state, characterized by the presence of powerful repulsive forces. It was these forces that served as the physical cause of the "Big Bang" and the subsequent rapid expansion of the Universe.

Consideration of the causes and consequences of the cosmological "Big Bang" would not be complete without one more physical concept. It is about the so-called phase transition (transformation), i.e. qualitative transformation of a substance, accompanied by an abrupt change from one state to another. Soviet physicists D.A. Kirzhnits and A.D. Linde were the first to notice that in the initial phase of the formation of the Universe, when cosmic matter was in a super-hot, but already cooling state, similar physical processes (phase transitions) could occur.

Further study of the cosmological consequences of phase transitions with broken symmetry led to new theoretical discoveries and generalizations. Among them is the discovery of a previously unknown epoch in the self-development of the Universe. It turned out that during the cosmological phase transition it could reach a state of extremely rapid expansion, in which its dimensions increased many times, and the density of the substance remained practically unchanged. The initial state that gave rise to the swelling Universe is considered to be the gravitational vacuum. The abrupt changes accompanying the process of cosmological expansion of space are characterized by fantastic numbers. So it is assumed that the entire observable Universe arose from a single vacuum bubble less than 10 to minus 33 degrees of cm! The vacuum bubble from which our Universe was formed had a mass equal to only one hundred thousandth of a gram.

At present, there is still no comprehensively tested and universally recognized theory of the origin of the large-scale structure of the Universe, although scientists have made significant progress in understanding the natural ways of its formation and evolution. Since 1981, the development of a physical theory of an inflating (inflationary) Universe began. To date, physicists have proposed several versions of this theory. It is assumed that the evolution of the Universe, which began with a grandiose general space cataclysm called the "Big Bang", was subsequently accompanied by a repeated change in the expansion regime.

According to scientists' assumptions, 10 to minus forty-third power of seconds after the "Big Bang", the density of superhot cosmic matter was very high (10 to 94 degrees of gram / cm cubic). The density of the vacuum was also high, although in order of magnitude it was much less than the density of ordinary matter, and therefore the gravitational effect of the primordial physical "emptiness" was invisible. However, during the expansion of the Universe, the density and temperature of matter fell, while the density of the vacuum remained unchanged. This circumstance led to a sharp change in the physical situation already 10 to minus 35 degrees of a second after the "Big Bang". The density of the vacuum is first compared, and then, after several super-instants of cosmic time, it becomes larger. Then the gravitational effect of vacuum makes itself felt - its repulsive forces again prevail over the gravitational forces of ordinary matter, after which the Universe begins to expand at an extremely fast rate (swells) and reaches enormous sizes in an infinitely small fraction of a second. However, this process is limited in time and space. The Universe, like any expanding gas, first quickly cools down and already in the region of 10 to minus 33 degrees of a second after the "Big Bang" is strongly supercooled. As a result of this universal "cooling" the Universe from one phase passes into another. We are talking about a phase transition of the first kind - an abrupt change in the internal structure of cosmic matter and all associated physical properties and characteristics. At the final stage of this cosmic phase transition, the entire energy reserve of the vacuum is converted into thermal energy of ordinary matter, and as a result, the universal plasma is again heated to its initial temperature, and, accordingly, the regime of its expansion changes.

No less interesting, and in a global perspective is more important, is another result of the latest theoretical research - the fundamental possibility of avoiding the initial singularity in its physical sense... We are talking about a completely new physical view of the problem of the origin of the Universe.

It turned out that contrary to some recent theoretical predictions (that the initial singularity cannot be avoided even with quantum generalization general theory relativity), there are certain microphysical factors that can prevent the unlimited compression of matter under the action of gravitational forces.

Back in the late thirties, it was theoretically discovered that stars with a mass exceeding the mass of the Sun by more than three times, at the last stage of their evolution, irrepressibly shrink to a singulatory state. The latter, in contrast to the singularity of the cosmological type, called the Friedmann one, is called the Schwarzschild one (after the German astronomer who first considered the astrophysical consequences of Einstein's theory of gravitation). But from a purely physical point of view, both types of singularity are identical. Formally, they differ in that the first singularity is the initial state of the evolution of matter, while the second is the final one.

According to recent theoretical concepts, the gravitational collapse should end with the compression of matter literally "to a point" - to a state of infinite density. According to the latest physical concepts, the collapse can be stopped somewhere in the region of the Planck density, i.e. at the turn of 10 to 94 degrees gram / cm cubic. This means that the Universe resumes its expansion not from scratch, but having a geometrically defined (minimum) volume and a physically acceptable, regular state.

Academician M.A. Markov put forward an interesting version of a pulsating Universe. In the logical framework of this cosmological model, old theoretical difficulties, if not finally solved, are at least illuminated from a new perspective angle of view. The model is based on a hypothesis according to which, with a sharp decrease in distance, the constants of all physical interactions tend to zero. This assumption is a consequence of another assumption, according to which the constant of gravitational interaction depends on the degree of density of the substance.

According to Markov's theory, whenever the Universe passes from the Friedmann stage (final compression) to the De Sitter stage (initial expansion), its physical and geometric characteristics turn out to be the same. Markov believes that this condition is quite enough to overcome the classic difficulty on the path of physical realization of the eternally oscillating Universe.

1) In the circle of eternal return? Three hypotheses .-- M.: Knowledge, 1989.- 48 p. - (New in life, science, technology. Ser. "Question mark"; No. 4).

2) How does a time machine work? - M.: Knowledge, 1991 .-- 48p. - (Subscription popular science series "Question mark"; No. 5).

3) Concise Philosophical Dictionary, ed. M. Rosenthal and P. Yudin. Ed. 4, add. and rev. ... M - state. ed. polit. lit. , 1954.

4) Who, When, Why? - state ed. children lit. , Ministry of Education of the RSFSR, Moscow - 1961.

5) The origin of the solar system. Ed. G. Reeves. Per. from English and French. ed. G.A. Leikin and V.S. Safronov. M, "WORLD", 1976.

6) Ukrainian Soviet Encyclopedic Dictionary. In 3 volumes / Editorial board: answer. ed. A.V. Kudritsky - K .: Head. ed. USE, - 1988.

7) Man and the Universe: The View of Science and Religion .-- M .: Sov. Russia 1986.

8) What are the "archaeologists of space" looking for? - M.: Knowledge, 1989. - 48 p., With illustrations - (New in life, science, technology. Ser. "Question mark"; No. 12)

9) What is it? Who it? : In 3 volumes. T. 1. - 3rd ed., Revised. Ch 80 and additional - M.: "Pedagogy-press", 1992. - 384 p. : ill.

10) Conversations about the Universe .-- M.: Politizdat, 1984 .-- 111p. - (Conversations about the world and man).

Science of celestial bodies

First letter "a"

Second letter "c"

Third letter "t"

The last beech letter "I"

The answer to the question "Science of celestial bodies", 10 letters:
astronomy

Alternative crossword questions for astronomy

What was the patronage of the muse of Urania?

Science of the universe

Caroline Herschel assisted brother William since 1782 and became one of the first women in this science

One of the seven liberal sciences

Definition of astronomy in dictionaries

Dictionary Russian language. S.I.Ozhegov, N.Yu.Shvedova. The meaning of the word in the dictionary Explanatory dictionary of the Russian language. S.I.Ozhegov, N.Yu.Shvedova.
-and, w. The science of cosmic bodies, their systems and the Universe as a whole. adj. astronomical, th, th. Astronomical unit (distance from the Earth to the Sun). Astronomical number (trans.: Extremely large).

Encyclopedic Dictionary, 1998 The meaning of the word in the dictionary Encyclopedic Dictionary, 1998
ASTRONOMY (from astro ... and Greek nomos - law) is the science of the structure and development of cosmic bodies, the systems they form and the Universe as a whole. Astronomy includes spherical astronomy, practical astronomy, astrophysics, celestial mechanics, stellar astronomy, ...

Explanatory dictionary of the Russian language. D.N. Ushakov The meaning of the word in the dictionary Explanatory dictionary of the Russian language. D.N. Ushakov
astronomy, pl. no, well. (from the Greek astron - star and nomos - law). The science of celestial bodies.

New explanatory and derivational dictionary of the Russian language, T. F. Efremova. Meaning of the word in the dictionary New explanatory and derivational dictionary of the Russian language, T.F. Efremova.
f. A complex scientific discipline that studies the structure and development of cosmic bodies, their systems and the Universe as a whole. An academic subject containing the theoretical foundations of this scientific discipline. colloquial A textbook outlining the content of the subject.

Great Soviet Encyclopedia Definition of the word in the dictionary Great Soviet Encyclopedia
"Astronomy", an abstract journal of the All-Union Institute of Scientific and Technical Information of the Academy of Sciences of the USSR. Published in Moscow since 1963 (in 1953-1962 the abstract journal Astronomy and Geodesy was published); 12 issues per year. Publishes abstracts, abstracts or bibliographic ...

Examples of the use of the word astronomy in literature.

The ancient pilotage of the Sea of ​​Azov coexisted with textbooks astronomy and navigation.

Just as these concrete problems, solved by algebraic methods, cannot be considered part of the abstract science of algebra, so, in my opinion, concrete problems astronomy cannot in any way be included in that department of abstract-concrete science that develops the theory of action and reaction of free bodies that attract each other.

So it was with the discovery that the refraction and scattering of light do not follow the same law of change: this discovery had an effect on both astronomy and physiology, giving us achromatic telescopes and microscopes.

Soon Biruni begins to seriously deal with issues astronomy having achieved important results already at the age of 21.

Matthew Vlastar is completely correct from the point of view astronomy explains this over time violation.

The starry sky has long excited the human imagination. Our distant ancestors tried to understand what kind of strange flickering dots hang over their heads. How many of them, where did they come from, do they affect earthly events? Since ancient times, man has tried to comprehend how the universe in which he lives is arranged.

About how ancient people imagined the Universe, today we can learn only from fairy tales and legends that have come down to us. It took centuries and millennia for the emergence and strengthening of the science of the Universe, which studies its properties and stages of development - cosmology. Astronomy, mathematics and physics are the cornerstones of this discipline.

Today we understand the structure of the Universe much better, but each knowledge gained only gives rise to new questions. The study of atomic particles in a collider, observation of life in the wild, the landing of an interplanetary probe on an asteroid can also be called the study of the Universe, because these objects are part of it. Man is also a part of our beautiful stellar universe. By studying the solar system or distant galaxies, we learn more about ourselves.

Cosmology and objects of its study

The very concept of the universe has no clear definition in astronomy. In different historical periods and among different peoples, it had a number of synonyms, such as "space", "world", "universe", "universe" or "celestial sphere". Often, speaking about the processes taking place in the depths of the Universe, the term "macrocosm" is used, the opposite of which is the "microcosm" of the world of atoms and elementary particles.

On the difficult path of cognition, cosmology often intersects with philosophy and even theology, and this is not surprising. The science of the structure of the Universe is trying to explain when and how the universe arose, to unravel the mystery of the origin of matter, to understand the place of the Earth and humanity in the infinity of space.

Have modern cosmology two biggest problems... First, the object of its study - the Universe - is unique, which makes it impossible to use statistical schemes and methods. In short, we do not know about the existence of other Universes, their properties, structure, therefore we cannot compare. Secondly, the duration of astronomical processes does not make it possible to carry out direct observations.

Cosmology proceeds from the postulate that the properties and structure of the Universe are the same for any observer, except for rare cosmic phenomena. This means that matter in the Universe is distributed uniformly, and it has the same properties in all directions. It follows from this that the physical laws operating in a part of the Universe can be extrapolated to the entire Metagalaxy.

Theoretical cosmology develops new models that are then confirmed or refuted by observations. For example, the theory of the origin of the universe as a result of an explosion has been proven.

Age, size and composition

The scale of the universe is amazing: it is much larger than we could have imagined twenty or thirty years ago. Scientists have already discovered about five hundred billion galaxies, and the number is constantly increasing. Each of them rotates around its own axis and moves away from the others at a tremendous speed due to the expansion of the Universe.

Quasar 3C 345 - one of the brightest objects in the Universe - is located at a distance of five billion light years from us. Human mind cannot even imagine such distances. A spaceship traveling at light speed will take a thousand years to orbit our Milky Way. It would take him 2.5 thousand years to get to the Andromeda galaxy. But this is the closest neighbor.

Speaking about the size of the Universe, we mean its visible part, also called the Metagalaxy. The more observations we get, the further the boundaries of the Universe expand. Moreover, this happens simultaneously in all directions, which proves its spherical shape.

Our world appeared about 13.8 billion years ago as a result of the Big Bang - an event that gave birth to stars, planets, galaxies and other objects. This figure is the real age of the universe.

Based on the speed of light, it can be assumed that its dimensions are also 13.8 billion light years. However, in reality they are larger, because from the moment of birth, the Universe has been continuously expanding. Part of it moves with superluminal speed, which is why a significant number of objects in the Universe will remain invisible forever. This limit is called the Hubble sphere or horizon.

The diameter of the Metagalaxy is 93 billion light years. We do not know what is outside the known universe. Perhaps there are more distant objects that are inaccessible today for astronomical observations. A significant part of scientists believe in the infinity of the universe.

The age of the universe has been checked many times using various techniques and scientific instruments. It was last confirmed with the Planck orbiting telescope. The available data are fully consistent with modern models of the expansion of the Universe.

What is the universe made of? Hydrogen is the most widespread element in the Universe (75%), in second place is helium (23%), the remaining elements account for an insignificant 2% of the total amount of matter. The average density is 10-29 g / cm3, a significant part of which falls on the so-called dark energy and matter. Ominous names do not speak of their inferiority, just dark matter, unlike ordinary matter, does not interact with electromagnetic radiation. Accordingly, we cannot observe it and draw our conclusions only on the basis of indirect evidence.

Based on the above density, the mass of the Universe is approximately 6 * 1051 kg. It should be understood that this figure does not include dark mass.

The structure of the universe: from atoms to galactic clusters

Space is not just a huge void in which stars, planets and galaxies are evenly scattered. The structure of the universe is quite complex and has several levels of organization, which we can classify according to the scale of objects:

1. Astronomical bodies in the universe are usually grouped into systems. Stars often form pairs or are part of clusters that contain tens or even hundreds of stars. In this respect, our Sun is rather atypical, since it has no "twin";
2. The next stage of organization is the galaxies. They can be spiral, elliptical, lenticular, irregular. Scientists do not yet fully understand why galaxies have different shapes. At this level, we discover such wonders of the universe as black holes, dark matter, interstellar gas, binary stars. In addition to stars, they include dust, gas, electromagnetic radiation... Several hundred billion galaxies have been discovered in the known Universe. They often collide with each other. It's not like a car accident: the stars just shuffle and change their orbits. Such processes take millions of years and lead to the formation of new star clusters;
3. Several galaxies form the Local Group. Ours, in addition to the Milky Way, includes the Triangle Nebula, the Andromeda Nebula and 31 other systems. Clusters of galaxies are the largest known stable structures in the Universe, they are held together by gravitational force and some other factor. Scientists have calculated that gravity alone is clearly not enough to maintain the stability of these objects. There is no scientific basis for this phenomenon yet;
4. The next level of the structure of the Universe is superclusters of galaxies, each of which contains tens or even hundreds of galaxies and clusters. However, gravity no longer holds them, so they follow the expanding universe;
5. The last level of organization of the universe are cells or bubbles, the walls of which form superclusters of galaxies. Between them are void areas called voids. These structures of the Universe have scales of about 100 Mpc. At this tier, the processes of the expansion of the Universe are most noticeable; relic radiation is also associated with it - an echo of the Big Bang.

How the universe came into being

How did the universe come about? What happened up to this point? How did it become that endless space as we know it today? Was it an accident or a natural process?

After decades of debate and fierce debate, physicists and astronomers have practically come to a consensus that the universe emerged from an explosion of colossal power. He not only gave birth to all matter in the Universe, but also determined the physical laws according to which the cosmos known to us exists. This is called the Big Bang theory.

According to this hypothesis, once all matter in some incomprehensible way was collected in one small point with infinite temperature and density. It is called the singularity. 13.8 billion years ago, the point exploded, forming stars, galaxies, their clusters and other astronomical bodies of the Universe.

Why and how this happened is unclear. Scientists have to bracket many questions related to the nature of the singularity and its origin: a complete physical theory of this stage in the history of the Universe does not yet exist. It should be noted that there are other theories of the origin of the Universe, but they have much fewer adherents.

The term "Big Bang" came into circulation in the late 40s after the publication of the work of the British astronomer Hoyle. Today, this model has been thoroughly worked out - physicists can confidently describe the processes that took place a fraction of a second after this event. You can also add that this theory made it possible to determine the exact age of the Universe and describe the main stages of its evolution.

The main evidence of the Big Bang theory is the presence of relic radiation. It was opened in 1965. This phenomenon arose as a result of the recombination of hydrogen atoms. The relic radiation can be called the main source of information about how the Universe was arranged billions of years ago. It fills space isotropically and uniformly.

Another argument in favor of the objectivity of this model is the very fact of the expansion of the Universe. In fact, extrapolating this process into the past, scientists have come to a similar concept.

There are also weaknesses in the Big Bang theory. If the universe was formed instantly from one small point, then there should have been a non-uniform distribution of matter, which we do not observe. Also, this model cannot explain where the antimatter went, the amount of which at the “moment of creation” should not have been inferior to ordinary baryonic matter. However, now the number of antiparticles in the Universe is scanty. But the most significant drawback of this theory is its inability to explain the Big Bang phenomenon, it is simply perceived as a fait accompli. We don't know what the universe looked like before the singularity.

There are other hypotheses of the origin and further evolution of the universe. The stationary Universe model has been popular for many years. A number of scientists were of the opinion that as a result of quantum fluctuations, it arose from a vacuum. Among them was the famous Stephen Hawking. Lee Smolin put forward the theory that ours, like other universes, formed inside black holes.

Attempts have been made to improve the existing Big Bang theory. For example, there is a hypothesis about the cyclicity of the Universe, according to which, birth from a singularity is nothing more than its transition from one state to another. True, this approach contradicts the second law of thermodynamics.

The evolution of the universe or what happened after the Big Bang

The Big Bang theory allowed scientists to create an accurate model of the evolution of the Universe. And today we know quite well what processes took place in the young Universe. The only exception is the earliest stage of creation, which continues to be the subject of intense discussion and controversy. Of course, to achieve a similar result, one theoretical basis was not enough, it took years of research into the universe and thousands of experiments on accelerators.

Science today identifies the following stages after the Big Bang:

1. The earliest of the known periods is called the Planck era, it takes a segment from 0 to 10-43 seconds. At this time, all the matter and energy of the universe was collected at one point, and the four basic interactions were one;
2. Age of Great Unification (from 10-43 to 10-36 seconds). It is characterized by the appearance of quarks and the separation of the main types of interactions. The main event of this period is the release of gravitational force. In this era, the laws of the universe began to form. Today we have the opportunity for a detailed description of the physical processes of this era;
3. The third stage of creation is called the Age of Inflation (from 10-36 to 10-32). At this time, the rapid movement of the Universe began at a speed significantly exceeding the speed of light. It is becoming larger than the present-day visible universe. Cooling starts. In this period, the fundamental forces of the universe are finally divided;
4. In the period from 10−32 to 10−12 seconds, "exotic" particles such as the Higgs boson appear, space is filled with quark-gluon plasma. The interval from 10-12 to 10-6 seconds is called the epoch of quarks, from 10-6 to 1 second - hadrons, in 1 second after the Big Bang the era of leptons begins;
5. Nucleosynthesis phase. It lasted until about the third minute from the beginning of the events. During this period, atoms of helium, deuterium, hydrogen arise from particles in the Universe. Cooling continues, space becomes transparent to photons;
6. Three minutes after the Big Bang, the era of Primary recombination begins. During this period, relic radiation appeared, which astronomers are still studying;
7. The period 380 thousand - 550 million years is called the Dark Ages. The universe at this time is filled with hydrogen, helium, and various types of radiation. There were no sources of light in the universe;
8. 550 million years after Creation, stars, galaxies and other wonders of the universe appear. The first stars explode, freeing matter to form planetary systems. This period is called the Era of Reionization;
9. At the age of 800 million years, the first stellar systems with planets begin to form in the Universe. The Age of Substance is coming. During this period, our home planet is also being formed.

It is believed that interest for cosmology is the period from 0.01 seconds after the act of creation to the present day. During this time period, the primary elements were formed, from which stars, galaxies, solar system... For cosmologists, the era of recombination is considered a particularly important period, when relic radiation arose, with the help of which the study of the known Universe continues.

History of cosmology: the earliest period

Man has been thinking about the structure of the world around him since time immemorial. The earliest ideas about the structure and laws of the Universe can be found in fairy tales and legends. different nations the world.

It is believed that regular astronomical observations were first practiced in Mesopotamia. Several advanced civilizations consistently lived on this territory: Sumerians, Assyrians, Persians. We can learn about how they imagined the universe from the many cuneiform tablets found on the site of ancient cities. The first records concerning the movement of celestial bodies date back to the VI millennium BC.

Of the astronomical phenomena, the Sumerians were most interested in cycles - the changes of the seasons and the phases of the moon. The future harvest and the health of domestic animals, therefore, the survival of the human population depended on them. From this, a conclusion was drawn about the influence of celestial bodies on the processes taking place on Earth. Therefore, studying the Universe, you can predict your future - this is how astrology was born.

The Sumerians invented a pole to determine the height of the Sun, created a solar and lunar calendar, described the main constellations, and discovered some of the laws of celestial mechanics.

Much attention was paid to the movement of space objects in religious practices Ancient egypt... The inhabitants of the Nile Valley used a geocentric model of the universe in which the sun revolved around the earth. Many ancient Egyptian texts containing astronomical information have come down to us.

The science of the sky reached significant heights in ancient China. Here, back in the III millennium BC. e. the post of court astronomer appeared, and in the XII century BC. e. the first observatories were opened. About solar eclipses, flyby of comets, meteor showers and other interesting cosmic events of antiquity, we mainly know from the Chinese chronicles and chronicles, which were scrupulously kept for centuries.

The Hellenes held astronomy in high esteem. They studied this issue numerous philosophical schools, each of which, as a rule, had its own system of the universe. The Greeks were the first to put forward the assumption about the spherical shape of the Earth and the rotation of the planet around its own axis. Astronomer Hipparchus introduced the concepts of apogee and perigee, orbital eccentricity, developed models of the motion of the Sun and Moon, and calculated the periods of revolution of the planets. A great contribution to the development of astronomy was made by Ptolemy, who can be called the creator of the geocentric model of the solar system.

The Maya civilization reached great heights in the study of the laws of the Universe. This is confirmed by the results of archaeological excavations. The priests knew how to predict solar eclipses, they created a perfect calendar, built numerous observatories. Mayan astronomers observed nearby planets and were able to pinpoint their orbital periods.

Middle Ages and Modern Times

After the collapse of the Roman Empire and the spread of Christianity, Europe plunged into the Dark Ages for almost a millennium - development natural sciences, including astronomy, practically stopped. Europeans drew information about the structure and laws of the Universe from biblical texts, a few astronomers firmly adhered to Ptolemy's geocentric system, astrology enjoyed unprecedented popularity. The real study of the universe by scientists began only in the Renaissance.

At the end of the 15th century, Cardinal Nikolai Kuzansky put forward a bold idea of ​​the universality of the universe and the infinity of the depths of the universe. Already by the 16th century, it became clear that Ptolemy's views were erroneous, and without the adoption of a new paradigm further development science is unthinkable. The Polish mathematician and astronomer Nicolaus Copernicus decided to break the old model and proposed a heliocentric model of the solar system.

From a modern point of view, his concept was imperfect. In Copernicus, the movement of the planets was provided by the rotation of the celestial spheres to which they were attached. The orbits themselves were circular, and on the border of the world was a sphere with fixed stars. However, by placing the Sun at the center of the system, the Polish scientist undoubtedly made a real revolution. The history of astronomy can be divided into two large parts: the oldest period and the study of the universe from Copernicus to the present day.

In 1608, the Italian scientist Galileo invented the world's first telescope, which gave a huge boost to the development of observational astronomy. Now scientists could contemplate the depths of the universe. It turned out that the Milky Way consists of billions of stars, the Sun has spots, the Moon has mountains, and satellites revolve around Jupiter. The advent of the telescope caused a real boom in optical observations of the wonders of the universe.

In the middle of the 16th century, the Danish scientist Tycho Brahe was the first to begin regular astronomical observations. He proved the cosmic origin of comets, thereby refuting Copernicus's idea of ​​the celestial spheres. At the beginning of the 17th century, Johannes Kepler solved the mysteries of planetary motion by formulating his famous laws. At the same time, the Andromeda and Orion nebulae, the rings of Saturn were discovered, and the first map of the lunar surface was compiled.

In 1687, Isaac Newton formulated the law of universal gravitation, which explains the interaction of all components of the universe. He made it possible to see the hidden meaning of Kepler's laws, which, in fact, were deduced empirically. The principles discovered by Newton allowed scientists to look at the space of the Universe in a new way.

The 18th century was a period of rapid development of astronomy, significantly expanding the boundaries of the known universe. In 1785, Kant put forward the brilliant idea that the Milky Way is a huge star cluster pulled together by gravity.

At this time, new celestial bodies appeared on the "map of the Universe", telescopes were improved.

In 1785, the English astronomer Herschel, based on the laws of electromagnetism and Newtonian mechanics, tried to create a model of the Universe and determine its shape. However, he failed.

In the 19th century, the instruments of scientists became more accurate, photographic astronomy appeared. Spectral analysis, which appeared in the middle of the century, led to a real revolution in observational astronomy - now the chemical composition of objects has become a topic for research. The asteroid belt was discovered, the speed of light was measured.

The era of breakthroughs or modern times

The twentieth century was the era of real breakthroughs in astronomy and cosmology. At the beginning of the century, Einstein showed the world his theory of relativity, which made a real revolution in our understanding of the universe and allowed us to look at the properties of the universe in a new way. In 1929, Edwin Hubble discovered that our universe was expanding. In 1931, Georges Lemaitre put forward the idea of ​​its formation from one tiny point. In fact, this was the beginning of the Big Bang theory. In 1965, relic radiation was discovered, which confirmed this hypothesis.

In 1957, the first artificial satellite was sent into orbit, after which space age... Now astronomers could not only observe celestial bodies in telescopes, but also to study them up close with the help of interplanetary stations and descent probes. We were even able to land on the lunar surface.

The 90s can be called “the period of dark matter”. Her discovery explained the acceleration of the expansion of the universe. At this time, new telescopes were put into operation, allowing us to expand the boundaries of the known Universe.

In 2016, gravitational waves were discovered, which will likely mark the beginning of a new branch of astronomy.

Over the past centuries, we have significantly expanded the boundaries of our knowledge of the Universe. However, in fact, people only opened the door and looked into a huge and wonderful world, full of secrets and amazing wonders.

If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.