A message on the topic of exploring the universe. Essay on the origin of the universe
You can use the “Space Exploration” report for children in preparation for the lesson.
"Space Exploration" report
Even in ancient times, people, observing the sky, used various measuring instruments that made it possible to determine the position of bodies in the sky.
But the invention of the telescope helped people explore space. With the help of telescopes, people have been able to discover many celestial bodies. These are various planets, stars, black holes, dwarfs, nebulae, quasars, comets and the like.
Today, in many countries around the world there are huge observatories where scientists conduct space research.
In the fifties of the last century, artificial Earth satellites were launched into space, and in 1961, a person visited space for the first time. It was the Soviet cosmonaut Yuri Gagarin. In 1969, American astronauts landed on the moon.
Telescopes launched into Earth orbit allow us to peer into the distant corners of the Universe.
Among the most famous telescopes, which made many discoveries and lifted the veil of deep space, was the Hubble telescope. The telescope was installed in orbit in 1990. Astronomers began to find the first planets outside our native solar system two years after its launch.
Nowadays, with the help of automatic spacecraft, scientists conduct space exploration; such devices fly to the planets of the solar system.
Spacecraft that are designed to carry out work in deep space are sent there irrevocably. Their flight often lasts for years, and during this period they transmit various information to Earth that they received during the flight.
The number of vehicles sent into deep space is very small. An example is the Voyager-1 and Voyager-2 spacecraft, which were launched in 1977. Both devices have energy and fuel to operate almost until 2020-2025. During this time, Voyager 1 will move away from the Sun by about 19 billion km, and Voyager 2 by almost 15 billion km. After -6-10 years, communication with the devices will almost certainly cease, they will become dead piles of metal.
PLAN
1. Origin of the Universe
2. Model of the expanding Universe
3. Evolution and structure of galaxies
4. Astronomy and cosmonautics
Origin of the Universe
At all times, people wanted to know where and how the world came from. When mythological ideas dominated the culture, the origin of the world was explained, as, say, in the Vedas, by the disintegration of the first man Purusha. The fact that this was a general mythological scheme is confirmed by Russian apocrypha, for example, the “Pigeon Book”. The victory of Christianity confirmed the idea of God creating the world out of nothing.
With the advent of science in its modern understanding, mythological and religious ones are replaced by scientific ideas about the origin of the Universe. Three related terms should be distinguished: being, universe and Universe. The first is philosophical and denotes everything that exists and exists. The second is used both in philosophy and in science, without having a specific philosophical load (in terms of contrasting being and consciousness), and denotes everything as such.
The meaning of the term Universe is narrower and has acquired a specifically scientific meaning. The Universe is the place of human habitation, accessible to empirical observation. The gradual narrowing of the scientific meaning of the term Universe is quite understandable, since natural science, unlike philosophy, deals only with what is empirically verifiable by modern scientific methods.
The Universe as a whole is studied by a science called cosmology, i.e. the science of space. This word is also not accidental. Although space now refers to everything outside the Earth's atmosphere, this was not the case in Ancient Greece. Space was then accepted as “order”, “harmony”, as opposed to “chaos” - “disorder”. Thus, cosmology, at its core, as befits science, reveals the orderliness of our world and is aimed at finding the laws of its functioning. The discovery of these laws is the goal of studying the Universe as a single ordered whole.
This study is based on several premises. Firstly, the universal laws of the functioning of the world formulated by physics are considered to be valid throughout the entire Universe. Secondly, the observations made by astronomers are also recognized as extending to the entire Universe. And thirdly, only those conclusions are recognized as true that do not contradict the possibility of the existence of the observer himself, i.e., a person (the so-called anthropic principle).
The conclusions of cosmology are called models of the origin and development of the Universe. Why models? The fact is that one of the basic principles of modern natural science is the idea of the possibility of conducting a controlled and reproducible experiment on the object being studied at any time. Only if it is possible to carry out an infinite number of experiments, in principle, and they all lead to the same result, on the basis of these experiments a conclusion is made about the existence of a law to which the functioning of a given object is subject. Only in this case the result is considered completely reliable from a scientific point of view.
This methodological rule remains inapplicable to the Universe. Science formulates universal laws, and the Universe is unique. This is a contradiction that requires considering all conclusions about the origin and development of the Universe not as laws, but only as models, i.e., possible explanations. Strictly speaking, all laws and scientific theories are models, since they can be replaced in the process of development of science by other concepts, but models of the Universe are, as it were, more models than many other scientific statements.
Expanding Universe Model
The most generally accepted model in cosmology is the model of a homogeneous isotropic non-stationary hot expanding Universe, built on the basis of the general theory of relativity and the relativistic theory of gravity, created by Albert Einstein in 1916. This model is based on two assumptions: 1) the properties of the Universe are the same at all its points (homogeneity) and directions (isotropy); 2) the best known description of the gravitational field is Einstein's equations. From this follows the so-called curvature of space and the connection between curvature and mass (energy) density. Cosmology based on these postulates is relativistic.
An important point of this model is its nonstationarity. This is determined by two postulates of the theory of relativity: 1) the principle of relativity, which states that in all inertial systems all laws are preserved regardless of the speed at which these systems move uniformly and rectilinearly relative to each other; 2) experimentally confirmed constancy of the speed of light.
From the acceptance of the theory of relativity it followed as a consequence (the first to notice this was the Petrograd physicist and mathematician Alexander Aleksandrovich Friedman in 1922) that curved space cannot be stationary: it must either expand or contract. This conclusion was not noticed until the discovery of the so-called “red shift” by American astronomer Edwin Hubble in 1929.
Red shift is a decrease in the frequencies of electromagnetic radiation: in the visible part of the spectrum, lines are shifted towards its red end. The previously discovered Doppler effect stated that when any source of oscillation moves away from us, the oscillation frequency we perceive decreases, and the wavelength increases accordingly. When emitted, “reddening” occurs, i.e., the lines of the spectrum shift towards longer red wavelengths.
So, for all distant light sources, the red shift was recorded, and the further away the source was, the greater the degree. The red shift turned out to be proportional to the distance to the source, which confirmed the hypothesis about their removal, i.e., about the expansion of the Metagalaxy - the visible part of the Universe.
The red shift reliably confirms the theoretical conclusion that the region of our Universe with linear dimensions of the order of several billion parsecs is nonstationary for at least several billion years. At the same time, the curvature of space cannot be measured, remaining a theoretical hypothesis.
An integral part of the expanding Universe model is the idea of the Big Bang, which occurred somewhere around 12 -18 billion years ago. “At first there was an explosion. Not the kind of explosion that we are familiar with on Earth, which starts from a certain center and then spreads, capturing more and more space, but an explosion that happened everywhere simultaneously, filling all space from the very beginning, with every particle of matter rushing away from every other particles" (Weinberg S. The first three minutes. A modern view of the origin of the Universe. - M., 1981. - P. 30).
The initial state of the Universe (the so-called singular point): infinite mass density, infinite curvature of space and explosive expansion that slows down over time at a high temperature at which only a mixture of elementary particles (including photons and neutrinos) could exist. The hotness of the initial state was confirmed by the discovery in 1965 of the cosmic microwave background radiation of photons and neutrinos formed at the early stage of the expansion of the Universe.
An interesting question arises: what did the Universe form from? What was that from which it arose. The Bible states that God created everything out of nothing. Knowing that classical science formulated the laws of conservation of matter and energy, religious philosophers argued about what the biblical “nothing” meant, and some, for the sake of science, believed that nothing meant the original material chaos ordered by God.
Surprisingly, modern science admits (that is, it admits, but does not assert) that everything could have been created from nothing. “Nothing” in scientific terminology is called vacuum. Vacuum, which physics of the 19th century considered emptiness, according to modern scientific concepts, is a unique form of matter, capable of “giving birth” to material particles under certain conditions.
Modern quantum mechanics allows (this does not contradict the theory) that the vacuum can come into an “excited state”, as a result of which a field can be formed in it, and from it (which is confirmed by modern physical experiments) matter.
The birth of the Universe “out of nothing” means, from a modern scientific point of view, its spontaneous emergence from a vacuum, when a random fluctuation occurs in the absence of particles. If the number of photons is zero, then the field strength does not have a definite value (according to Heisenberg’s “uncertainty principle”): the field constantly experiences fluctuations, although the average (observed) value of the strength is zero.
Fluctuation represents the appearance of virtual particles that are continuously born and immediately destroyed, but also participate in interactions like real particles. Thanks to fluctuations, the vacuum acquires special properties that manifest themselves in the observed effects.
So, the Universe could have formed from “nothing,” that is, from an “excited vacuum.” Such a hypothesis, of course, is not a decisive confirmation of the existence of God. After all, all this could have happened in accordance with the laws of physics in a natural way without outside interference from any ideal entities. And in this case, scientific hypotheses do not confirm or refute religious dogmas, which lie on the other side of empirically confirmed and refuted natural science.
The amazing things in modern physics don’t end there. Responding to a journalist’s request to summarize the essence of the theory of relativity in one sentence, Einstein said: “It used to be believed that if all matter disappeared from the Universe, then space and time would be preserved; The theory of relativity states that along with matter, space and time would also disappear.” Transferring this conclusion to the model of the expanding Universe, we can conclude that before the formation of the Universe there was neither space nor time.
Note that the theory of relativity corresponds to two types of the expanding Universe model. In the first of them, the curvature of space-time is negative or in the limit equal to zero; in this option, all distances increase without limit over time. In the second version of the model, the curvature is positive, space is finite, and in this case, expansion is replaced over time by compression. In both versions, the theory of relativity is consistent with the current empirically confirmed expansion of the Universe.
The idle mind inevitably asks questions: what was there when there was nothing, and what is beyond expansion. The first question is obviously contradictory in itself, the second goes beyond the scope of specific science. An astronomer may say that as a scientist he has no right to answer such questions. But since they do arise, possible justifications for the answers are formulated, which are not so much scientific as natural philosophical.
Thus, a distinction is made between the terms “infinite” and “limitless.” An example of an infinity that is not limitless is the surface of the Earth: we can walk on it indefinitely, but nevertheless it is limited by the atmosphere above and the earth's crust below. The universe can also be infinite, but limited. On the other hand, there is a well-known point of view according to which there cannot be anything infinite in the material world, because it develops in the form of finite systems with feedback loops by which these systems are created in the process of transforming the environment.
But let us leave these considerations to the realm of natural philosophy, because in natural science, ultimately, the criterion of truth is not abstract considerations, but the empirical testing of hypotheses.
What happened after the Big Bang? A clot of plasma was formed - a state in which elementary particles are located - something between a solid and a liquid state, which began to expand more and more under the influence of the blast wave. 0.01 seconds after the start of the Big Bang, a mixture of light nuclei (2/3 hydrogen and 1/3 helium) appeared in the Universe. How were all the other chemical elements formed?
Evolution and structure of galaxies
The poet asked: “Listen! After all, if the stars light up, that means someone needs it?” We know that stars are needed to shine, and our Sun provides the energy necessary for our existence. Why are galaxies needed? It turns out that galaxies are also needed, and the Sun not only provides us with energy. Astronomical observations show that there is a continuous outflow of hydrogen from the nuclei of galaxies. Thus, the nuclei of galaxies are factories for the production of the main building material of the Universe - hydrogen.
Hydrogen, the atom of which consists of one proton in the nucleus and one electron in its orbit, is the simplest “building block” from which more complex atoms are formed in the depths of stars in the process of atomic reactions. Moreover, it turns out that it is no coincidence that stars have different sizes. The greater the mass of a star, the more complex atoms are synthesized in its depths.
Our Sun, like an ordinary star, produces only helium from hydrogen (which is produced by the cores of galaxies); very massive stars produce carbon - the main “building block” of living matter. That's what galaxies and stars are for. What is the Earth for? It produces all the necessary substances for the existence of human life. Why does man exist? Science can't answer this question, but it can make us think about it again.
If someone needs the “ignition” of the stars, then maybe someone needs a person too? Scientific data helps us formulate an idea of our purpose, the meaning of our lives. When answering these questions, turning to the evolution of the Universe means thinking cosmically. Natural science teaches us to think cosmically, while at the same time not breaking away from the reality of our existence.
The question of the formation and structure of galaxies is the next important question of the origin of the Universe. It is studied not only by cosmology as the science of the Universe - a single whole, but also by cosmogony (Greek “gonea” means birth) - a field of science that studies the origin and development of cosmic bodies and their systems (planetary, stellar, galactic cosmogony is distinguished) .
A galaxy is a giant cluster of stars and their systems that have their own center (core) and a different, not only spherical, but often spiral, elliptical, oblate or generally irregular shape. There are billions of galaxies, and each of them contains billions of stars.
Our galaxy is called the Milky Way and consists of 150 billion stars. It consists of a core and several spiral branches. Its dimensions are 100 thousand light years. Most of the stars in our galaxy are concentrated in a giant “disk” about 1,500 light-years thick. The Sun is located at a distance of about 30 thousand light years from the center of the galaxy.
The closest galaxy to ours (to which the light beam travels 2 million years) is the “Andromeda nebula”. It is named so because it was in the constellation Andromeda that the first extragalactic object was discovered in 1917. Its belonging to another galaxy was proven in 1923 by E. Hubble, who found stars in this object through spectral analysis. Later, stars were discovered in other nebulae.
And in 1963, quasars (quasi-stellar radio sources) were discovered - the most powerful sources of radio emission in the Universe with a luminosity hundreds of times greater than the luminosity of galaxies and sizes tens of times smaller than them. It was assumed that quasars represent the nuclei of new galaxies and, therefore, the process of galaxy formation continues to this day.
Astronomy and space exploration
Stars are studied by astronomy (from the Greek “astron” - star and “nomos” - law) - the science of the structure and development of cosmic bodies and their systems. This classical science is experiencing its second youth in the 20th century due to the rapid development of observation technology - its main method of research: reflecting telescopes, radiation receivers (antennas), etc. In the USSR, in 1974, a reflector with The mirror is 6 m in diameter, collecting light millions of times more than the human eye.
Astronomy studies radio waves, light, infrared, ultraviolet, x-rays and gamma rays. Astronomy is divided into celestial mechanics, radio astronomy, astrophysics and other disciplines.
Astrophysics, a part of astronomy that studies physical and chemical phenomena occurring in celestial bodies, their systems and in outer space, is currently acquiring particular importance. Unlike physics, which is based on experiment, astrophysics is based primarily on observations. But in many cases, the conditions in which matter is found in celestial bodies and systems differ from those available to modern laboratories (ultra-high and ultra-low densities, high temperatures, etc.). Thanks to this, astrophysical research leads to the discovery of new physical laws.
The intrinsic significance of astrophysics is determined by the fact that currently the main attention in relativistic cosmology is transferred to the physics of the Universe - the state of matter and physical processes occurring at different stages of the expansion of the Universe, including the earliest stages.
One of the main methods of astrophysics is spectral analysis. If you pass a beam of white sunlight through a narrow slit and then through a glass triangular prism, it breaks down into its component colors, and a rainbow color stripe appears on the screen with a gradual transition from red to violet - a continuous spectrum. The red end of the spectrum is formed by the rays that are the least deflected when passing through a prism, the violet end is the most deflected. Each chemical element corresponds to well-defined spectral lines, which makes it possible to use this method for studying substances.
Unfortunately, short-wave radiation - ultraviolet, x-rays and gamma rays - do not pass through the Earth’s atmosphere, and here science comes to the aid of astronomers, which until recently was considered primarily technical - astronautics (from the Greek “nautike” - the art of navigation) , providing space exploration for the needs of mankind using aircraft.
Cosmonautics studies problems: theories of space flight - calculations of trajectories, etc.; scientific and technical - design of space rockets, engines, on-board control systems, launch facilities, automatic stations and manned spacecraft, scientific instruments, ground-based flight control systems, trajectory measurement services, telemetry, organization and supply of orbital stations, etc.; medical and biological - the creation of on-board life support systems, compensation for adverse phenomena in the human body associated with overload, weightlessness, radiation, etc.
The history of astronautics begins with theoretical calculations of man's exit into unearthly space, which were given by K. E. Tsiolkovsky in his work “Exploration of world spaces with jet instruments” (1903). Work in the field of rocket technology began in the USSR in 1921. The first launches of liquid fuel rockets were carried out in the United States in 1926.
The main milestones in the history of astronautics were the launch of the first artificial Earth satellite on October 4, 1957, the first human flight into space on April 12, 1961, the lunar expedition in 1969, the creation of manned orbital stations in low-Earth orbit, and the launch of a reusable spacecraft.
The work was carried out in parallel in the USSR and the USA, but in recent years there has been a unification of efforts in the field of space exploration. In 1995, the joint Mir-Shuttle project was carried out, in which American Shuttle ships were used to deliver astronauts to the Russian orbital station Mir.
The ability to study cosmic radiation at orbital stations, which is delayed by the Earth's atmosphere, contributes to significant progress in the field of astrophysics.
Bibliography
1. Einstein A., Infeld L. Evolution of physics. M., 1965.
2. Heisenberg V. Physics and Philosophy. Part and whole. M., 1989.
3. A brief moment of triumph. M., 1989.
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All-Russian State Tax Academy under the Ministry of Finance of the Russian Federation
ABSTRACT
According to the Concept of Modern Natural Science
on the topic of:Origin of the Universe
Completed by: student gr. BZ-101
Larina A. B.Checked by: teacher
________________________
Moscow 2006
Content:
Introduction | page 3 |
| Education of the Universe | page 5 |
| Structure of the Galaxy. Types of Galaxies | page 7 |
| Earth - planet of the solar system | page 9 |
| Structure of the Earth | page 13 |
| Conclusion. | page 17 |
| List of used literature | page 18 |
Introduction
Universe- this is the entire existing material world, limitless in time and space and infinitely diverse in the forms that matter takes in the process of its development. The part of the Universe covered by astronomical observations is called Metagalaxy, or our Universe. The dimensions of the metagalaxy are very large: the radius of the cosmological horizon is 15-20 billion light years.Cosmology- one of those branches of natural science that are always at the intersection of sciences. The structure and evolution of the Universe are studied by cosmology. Cosmology uses the achievements and methods of physics, mathematics, and philosophy. The subject of cosmology is the entire megaworld around us, the entire “big Universe,” and the task is to describe the most general properties, structure and evolution of the universe.
Modern astronomy has not only discovered the grandiose world of galaxies, but also discovered unique phenomena: the expansion of the Metagalaxy, the cosmic abundance of chemical elements, relict radiation, indicating that the Universe is continuously evolving.
The evolution of the structure of the Universe is associated with the emergence of clusters of galaxies, the separation and formation of stars and galaxies, and the formation of planets and their satellites. The Universe itself arose approximately 20 billion years ago from some dense and hot proto-matter. There is a point of view that from the very beginning protomatter began to expand at a gigantic speed. At the initial stage, this dense substance scattered in all directions and was a homogeneous seething mixture of unstable particles that constantly disintegrated upon collision. Cooling and interacting over millions of years, this entire mass of matter scattered in space was concentrated into large and small gas formations, which over the course of hundreds of millions of years, approaching and merging, turned into huge complexes. In these complexes, in turn, denser areas arose - stars and even entire galaxies subsequently formed there.
As a result of gravitational instability, dense “protostellar formations” with masses close to the mass of the Sun can form in different zones of the formed galaxies. The compression process that has begun will accelerate under the influence of its own gravitational field. This process accompanies the free fall of cloud particles towards its center - gravitational compression occurs. In the center of the cloud a compaction forms, consisting of molecular hydrogen and helium. An increase in density and temperature in the center leads to the disintegration of molecules into atoms, ionization of atoms and the formation of a dense protostar core.
There is a hypothesis about the cyclical state of the Universe. Having once emerged from a super-dense clump of matter, the Universe may have already in its first cycle given birth to billions of star systems and planets within itself. And then the Universe begins to strive towards the state from which the history of the cycle began. Eventually, the matter of the Universe returns to its original super-dense state, destroying all life that got in its way. And this is repeated every time, in every cycle for eternity.
By the beginning of the 30s of the twentieth century. It is believed that the main components of the Universe are galaxies, each of which consists on average of 100 billion stars. The Sun, together with the planetary system, is part of our Galaxy, the bulk of whose stars we observe in the form of the Milky Way. In addition to stars and planets, the Galaxy contains a significant amount of rarefied gases and cosmic dust.
Education of the Universe.
Is the Universe finite or infinite, what is its geometry - these and many other questions are related to the evolution of the Universe, in particular to the observed expansion. If the speed of the “expansion” of galaxies increases by 75 km/s for every million parsecs, then extrapolation to the past leads to an amazing result: approximately 10-20 billion years ago the entire Universe was concentrated in a very small area. Many scientists believe that at that time the density of the Universe was the same as that of an atomic nucleus: the Universe was one giant “ nuclear drop" For some reason, this “drop” became unstable and exploded. We are now observing the consequences of this explosion as systems of galaxies.
With this estimate of the time of formation of the Universe, it was assumed that the picture of the expansion of galaxies that we now observe occurred at the same speed and in an arbitrarily distant past. And it is precisely on this assumption that the hypothesis of the primary Universe is based - a giant “nuclear drop” that has come to a state of instability.
Currently, cosmologists suggest that the Universe did not expand “from point to point,” but seemed to pulsate between finite limits of density. This means that in the past the speed of expansion of galaxies was less than now, and even earlier the system of galaxies was compressed, i.e. The galaxies approached each other at a higher speed, the greater the distance that separated them. Modern cosmology has a number of arguments in favor of the picture of a “pulsating Universe”. Such arguments are purely mathematical; the most important of them is the need to take into account the actually existing heterogeneity of the Universe. We cannot now decide which of the two hypotheses is correct. It will take a lot of work to solve this one of the most important problems in cosmology.
Modern cosmology arose at the beginning of the twentieth century. after the creation of the relativistic theory of gravity. The first relativistic model, based on a new theory of gravity and claiming to describe the entire Universe, was built by A. Einstein in 1917. However, it described a static Universe and, as astrophysical observations showed, it turned out to be incorrect.
In 1922-1924. Soviet mathematician A.A. Friedman proposed general equations to describe the entire Universe as it changes over time. Stellar systems cannot be located, on average, at constant distances from each other. They must either move away or come closer. This result is an inevitable consequence of the presence of gravitational forces, which dominate on a cosmic scale. Friedman's conclusion meant that the Universe must either expand or contract. This resulted in a revision of general ideas about the Universe. In 1929, the American astronomer E. Hubble (1889-1953), using astrophysical observations, discovered expansion of the universe, confirming the correctness of Friedman's conclusions.
Friedmann's models serve as the basis for all subsequent development of cosmology. They describe the mechanical picture of the movement of the huge masses of the Universe and its global structure. If previous cosmological constructions were designed to describe the now observable structure of the Universe with the average motion of the worlds in it unchanged, then Friedman’s models were essentially evolutionary, connecting the current state of the Universe with its previous history. From this theory it follows that in the distant past the Universe was completely different from what we observe today. Then there were neither individual celestial bodies nor their systems; all matter was almost homogeneous, very dense, and rapidly expanding. Only much later did galaxies and their clusters emerge from such matter.
Since the late 40s of our century, the physics of processes at different stages of cosmological expansion has attracted increasing attention in cosmology. In the G.A. put forward at this time. Gamow's theories hot universe nuclear reactions were considered that occurred at the very beginning of the expansion of the Universe in very dense matter. It was assumed that the temperature of the substance was high and fell with the expansion of the Universe. The theory predicted that the material from which the first stars and galaxies were formed should consist mainly of hydrogen (75%) and helium (25%), with an insignificant admixture of other chemical elements. Another conclusion of the theory is that in today’s Universe there should be weak electromagnetic radiation left over from the era of high density and temperature of matter. Such radiation during the expansion of the Universe was called cosmic microwave background radiation.
At the same time, fundamentally new observational capabilities appeared in cosmology: radio astronomy arose, and the capabilities of optical astronomy expanded. Now the Universe, down to distances of several parsecs, is being studied using different methods.
At the present stage in the development of cosmology, the problem of the beginning of cosmological expansion, when the densities of matter and particle energy were enormous, is being intensively studied. The guiding ideas are new discoveries in the physics of the interaction of elementary particles at very high energies. In this case, the global evolution of the Universe is considered. Today, the evolution of the Universe is comprehensively substantiated by numerous astrophysical observations, which are based on the theoretical basis of all physics.
Structure of the Galaxy. Types of Galaxies.
The stars surrounding the Sun and the Sun itself form a small part of a giant cluster of stars and nebulae, which is called Galaxy. The galaxy has a rather complex structure. A significant part of the stars in the Galaxy is located in a giant disk with a diameter of approximately 100 thousand and a thickness of about 1500 light years. This disk contains more than a hundred billion stars of various types. Our Sun is one of these stars, located on the periphery of the Galaxy near its equatorial plane.
Stars and nebulae within the Galaxy move in a rather complex way: they participate in the rotation of the Galaxy around an axis perpendicular to its equatorial plane. Different parts of the Galaxy have different rotation periods.
The stars are located at great distances from each other and are practically isolated from each other. They practically do not collide, although the movement of each of them is determined by the gravitational field created by all the stars of the Galaxy.
Astronomers have spent the last few decades studying other star systems similar to ours. This is very important research in astronomy. During this time, extragalactic astronomy has made amazing strides.
The number of stars in the Galaxy is about a trillion. The most numerous of them are dwarfs with masses approximately 10 times less than the mass of the Sun. The Galaxy includes double and multiple stars, as well as groups of stars bound by gravitational forces and moving in space as a single whole - star clusters. There are open star clusters, such as the Pleiades in the constellation Taurus. Such clusters do not have a regular shape; Currently, more than a thousand are known.
Globular star clusters are observed. If open clusters contain hundreds or thousands of stars, then globular clusters contain hundreds of thousands. Gravitational forces hold stars in such clusters for billions of years.
In various constellations, nebulous spots are found, which consist mainly of gas and dust - these are nebulae. They can be irregular, patchy in shape - diffuse, and regular in shape, resembling planets in appearance - planetary.
There are also bright diffuse nebulae, such as the Crab Nebula, named for its unusual network of openwork gas filaments. This is a source of not only optical radiation, but also radio radiation, x-rays and gamma rays. At the center of the Crab Nebula there is a source of pulsed electromagnetic radiation - pulsar, in which, along with pulsations of radio emission, optical pulsations of brightness and pulsations of X-ray emission were first discovered. A pulsar, which has a powerful alternating magnetic field, accelerates electrons and causes the nebula to glow in different parts of the electromagnetic wave spectrum.
Space in the Galaxy is filled everywhere with rarefied interstellar gas and interstellar dust. There are also various fields in interstellar space - gravitational and magnetic. Cosmic rays, which are streams of electrically charged particles that, when moving in magnetic fields, accelerate to speeds close to the speed of light and acquire enormous energy, penetrate interstellar space.
The galaxy can be thought of as a disk with a core at the center and huge spiral arms containing mostly the hottest and brightest stars and massive clouds of gas. The disk with spiral branches forms the basis of the flat subsystem of the Galaxy. And objects that concentrate towards the Galactic core and only partially penetrate into the disk belong to the spherical subsystem. The Galaxy itself rotates around its central region. Only a small fraction of stars are concentrated in the center of the Galaxy. The Sun is located at such a distance from the center of the Galaxy where the linear speed of stars is maximum. The Sun and the stars closest to it move around the center of the Galaxy at a speed of 250 km/s, completing a full revolution in approximately 290 million years.
Based on their appearance, galaxies are conventionally divided into three types: elliptical, spiral and irregular.
Spatial form elliptical galaxies– ellipsoids with different degrees of compression. Among them there are giant and dwarf ones. Almost a quarter of all studied galaxies are elliptical. These are the simplest galaxies in structure - the distribution of stars in them decreases evenly from the center, there is almost no dust and gas. They contain the brightest stars - red giants.
Spiral galaxies- the most numerous species. This includes our Galaxy and the Andromeda Nebula, which is approximately 2.5 million light years away from us.Irregular galaxies do not have central nuclei; no patterns have yet been discovered in their structure. These are the Large and Small Magellanic Clouds, which are satellites of our Galaxy. They are located from us at a distance of one and a half times the diameter of the Galaxy. The Magellanic Clouds are significantly smaller than our Galaxy in mass and size.
There are also interacting galaxies. They are usually located at short distances from each other, connected by “bridges” of luminous matter, and sometimes seem to penetrate one another.
Some galaxies have exceptionally powerful radio emissions, exceeding visible radiation. This radio galaxies.
In 1963, the discovery of star-like sources of radio emission began - quasars. Now there are more than a thousand of them open.
Earth is a planet in the solar system.
solar system is a group of celestial bodies, very different in size and physical structure. This group includes: the Sun, nine large planets, dozens of satellites of planets, thousands of small planets (asteroids), hundreds of comets, countless meteorite bodies moving both in swarms and in the form of individual particles. All these bodies are united into one system due to the gravitational force of the central body - the Sun.
The solar system is a very complex natural formation that combines the diversity of its constituent elements with the highest stability of the system as a whole.
According to the figurative statement of K. E. Tsiolkovsky, the Earth is the cradle of humanity.
In a certain sense, the Earth is distinguished by nature itself: in the solar system, only on this planet do developed forms of life exist, only on this planet the local ordering of matter has reached an unusually high level, continuing the general line of development of matter. It is on Earth that the most complex stage of self-organization has been passed, marking a deep qualitative leap to higher forms of order.
The differences between terrestrial planets and giant planets are obvious. But even among the closest neighbors of the Earth, no two planets are identical: they all differ in size, physical and chemical parameters, structure of the interior and surfaces, atmospheres and other characteristics. The main differences are determined by the initial conditions for the formation of planets - chemical composition, density of matter in those parts of the protoplanetary cloud where these planets were formed, distance from the Sun, resonant interactions with other planetary bodies and the Sun.
Direct studies of other nearby planets have just begun. Nevertheless, the available information already allows for a comparative study of the outer shells of the Earth and other planets of the Solar System. On this basis, a new scientific direction arose, called comparative planetology.
Earth is the largest planet in its group. But even such dimensions and mass turn out to be the minimum at which the planet is able to maintain its gas atmosphere. The Earth is rapidly losing hydrogen and some other light gases, which is confirmed by observations of the so-called Earth's plume. Venus is almost equal in size and mass to Earth, but it is closer to the Sun and receives more heat from it. Therefore, it has long ago lost all free hydrogen. The other two planets in this group either have no atmosphere (Mercury) or have remained in a very rarefied state (Mars).
The planets closest to the Sun - Mercury and Venus - rotate very slowly around their axis, with a period of tens to hundreds of Earth days. The slow rotation of these planets is due to their resonant interactions with the Sun and with each other. The Earth and Mars rotate with almost identical periods of about 24 hours. The Earth and Venus also form a resonant structure. In this group of planets, only Venus has a reverse rotation (opposite to the direction of rotation of the Sun around its axis); it is, as it were, turned “upside down” in its orbit. Finally, only the Earth in its group has a strong magnetic field of its own, which is more than two orders of magnitude greater than the magnetic fields of other planets.
None of the terrestrial planets has a developed system of satellites, which is typical for the planets of the Jupiter group. The Earth's planet-like satellite, the Moon, is close in size to the planet Mercury. The two satellites of Mars - Phobos and Deimos - have an irregular shape, resembling small asteroids. Until now, there is no clear idea about both the origin of the Moon and the origin of the satellites of Mars.
Three of the four terrestrial planets have a noticeable atmosphere. The atmosphere of each planet bears the imprint of the peculiarities of its development. The Earth's atmosphere is fundamentally different from the atmospheres of other planets: it has a low content of carbon dioxide, a high content of molecular oxygen and a relatively high content of water vapor. Two reasons create the isolation of the Earth’s atmosphere: the water of the oceans and seas absorbs carbon dioxide well, and the biosphere saturates the atmosphere with molecular oxygen formed during the process of plant photosynthesis. Calculations show that if we release all the carbon dioxide absorbed and bound in the oceans, simultaneously removing from the atmosphere all the oxygen accumulated as a result of the life of plants, then the composition of the earth’s atmosphere in its main features would become similar to the composition of the atmospheres of Venus and Mars.
The relatively small size of Mars did not allow it to retain a dense atmosphere. It is possible that earlier, when processes of active release of gases from the bowels of the planet took place, the atmosphere of Mars was much denser than it is now. Conditions near its surface were milder, without such sharp changes in day and night temperatures. There is very little water vapor in the Martian atmosphere, and therefore there is no cloudiness. But the movements of the rarefied atmosphere sometimes reach such strength that powerful dust storms arise on a planetary scale, raising masses of sand to a height of many kilometers. Then the surface of the planet is hidden for a long time behind an impenetrable curtain.
In the Earth's atmosphere, saturated water vapor creates a cloud layer covering a significant part of the planet. The Earth's clouds are the most important element in the hydrosphere-atmosphere-land system.
The surface reliefs of the Earth and the two planets closest to it are significantly different, which is explained, first of all, by differences in volcanic and geological processes on each of them. It is believed that tectonic activity can serve as a measure of the level of vitality of the planet as a whole. The reduction, and even more so the cessation of such activities is considered as a sign of the dying of the planet, the completion of the cycle of its evolutionary development. After all, the essence of such development is the active exchange of matter and energy between the interior and surface of the planet, during which the atmosphere, hydrosphere and the dominant types of surface topography are formed and maintained. With the cessation of tectonic activity, the planet turns into a dead celestial body, on which degradation processes predominate.
Tectonic processes are still actively occurring on Earth today; its geological history is far from complete. Paleontologists claim that in the early youth of the Earth, its tectonic activity was even higher. The modern topography of the planet has developed and continues to change under the influence of the combined action of tectonic, hydrosphere, atmospheric and biological processes on its surface. On other planets this combination of factors does not exist.
The relief of the earth's surface as a whole is characterized by a global asymmetry of two hemispheres (northern and southern): one of them is a gigantic space filled with water. These are oceans, occupying more than 70% of the entire surface. In the other hemisphere, the crustal uplifts that form the continents are concentrated. Oceanic and continental varieties of crust differ both in age and in chemical and geological composition. The topography of the ocean floor is different from the continental topography.
Systematic studies of the sea and ocean floor have become possible only recently. They have already led to a new understanding of the global nature of tectonic processes occurring on Earth. The average depth of the world's oceans is close to 4 km, individual depressions reach three times this depth, and individual cones rise significantly above the surface of the water. The main attraction of the oceanic relief is the global system of median ridges, stretching for tens of thousands of kilometers. Along their central parts there are faults, the so-called rift zones, through which fresh masses of matter emerge from the mantle to the surface. They push apart the oceanic crust, shaping it through a process of continuous renewal. The age of the oceanic crust does not exceed 150 million years. Another characteristic feature of the process is the existence of subduction zones, where the oceanic crust plunges under one of the island arcs (for example, under the Kuril, Mariana, etc.) or under the edge of the continent. Subduction zones are characterized by increased seismic and volcanic activity.
The relief of the continental part of the planet is more diverse: plains, hills, plateaus, mountain ranges and huge mountain systems. Some areas of land lie below ocean level (for example, the Dead Sea area), some mountain peaks are raised 8-9 km above its level. According to modern views, the continental crust, together with the underlying layers of the mantle, forms a system of lithospheric continental plates. Unlike the lithosphere of the oceans, continental plates have a very ancient origin, their age is estimated at 2.5-3.8 billion years. The thickness of the central part of some continental plates reaches 250 km.
At the boundaries of lithospheric plates, called geosynclines, either compression or extension of the crust occurs, which depends on the direction of local horizontal displacement of the plates.
Preliminary results of a comparative comparison of Earth, Venus and Mars can be formulated as follows:
· neither Venus nor Mars have even the simplest forms of life. The question remains open about the possible existence of some forms of life on Mars in the distant past.
· Only on Earth there is a powerful hydrosphere, formed simultaneously with the planet. While Mars supposedly had a form of hydrosphere in the past, Venus most likely never did.
· in the modern era, only the Earth remains a “living” planet, the geological development of which continues and manifests itself, in particular, in active tectonic activity. Mars and Venus went through periods of intense seismic and volcanic activity in the past, but this ceased on Mars several hundred million years ago, and on Venus more than a billion years ago. Both of these planets are most likely completing or have already completed the cycle of their evolutionary development.
· Numerous signs indicate that processes in the bowels of the earth have proceeded and continue to proceed differently than those of Venus and Mars. This is indicated by factors such as the existence of a continental crust with granite rocks, clearly defined lithospheric plates with their movements under the influence of deep processes, and the existence of a relatively powerful magnetic field near the Earth.
Advances in science and technology have made direct study of the planets of the solar system accessible, opening up fundamentally new opportunities for comparative knowledge of our own planet. Thus, a new page has been opened in understanding the world around us, but so far only the first lines have been written on it. The question still remains unresolved: what distinguished the Earth from the family of planets of the same type so that it could become an abode of life? The search for an answer to this question can only take place along the path of movement from the particular to the general, from the planet Earth with the life existing on it to the awareness of the cosmic nature of life - this most important link in the self-organization of matter in the process of the development of matter.
Structure of the Earth.
Numerous sciences about the Earth and its components have developed virtually independently of each other in the recent past. Now there is a conscious need to consider the planet as a single system, as an integral natural body, which has its own internal laws of development. The rapid introduction of such an idea into people's consciousness was facilitated by the outstanding event of our time - man's entry into near space. This made it possible to look at the Earth from the outside for the first time, to see it all at once, to clearly see the planetary scale of most atmospheric and surface phenomena, and the close interconnection of all external earthly spheres - land, water, air and the biosphere. The picture turned out to be impressive.
The totality of ideas emerging on the basis of a solid material base, in the form of accumulated facts, requires considering our planet not only as a single natural body, but also as a self-organizing system, the development of which is initiated by the confrontation of two fundamental natural tendencies - the desire to destroy orderliness and the desire to create more and more ordered systems.
Most of the special sciences about the Earth are the sciences about its surface, including the atmosphere. The Kola superdeep well is currently the deepest on Earth – 12-15 km. From depths of approximately 200 km, subsurface matter is carried out in different ways and becomes accessible to researchers. Information about deeper layers is obtained by indirect methods - based on recording the nature of the passage of seismic waves of different types through the bowels of the earth. Another group of methods is based on assumptions about the structure and composition of the protoplanetary cloud and on hypothetical assumptions about the process of formation of planets in it. Based on this, the matter of meteorites is considered as relict remains of the past, reflecting the composition and structure of the matter of the protoplanetary cloud in the zone of formation of the terrestrial planets. On this basis, conclusions are drawn about the coincidence of the substance of meteorites of a certain type with the substance of certain layers of the earth's depths. The matter of meteorites falls from space to Earth from time to time, and it is available for direct study. However, conclusions about the composition of the Earth's interior based on data on the chemical and mineralogical composition of meteorites falling on the Earth are not considered reliable.
Probing of the Earth's interior with seismic waves made it possible to establish their shell structure and differentiated chemical composition. There are three main concentrically located areas: core, mantle and crust. The core and mantle, in turn, are divided into additional shells that differ in physical and chemical properties. The core occupies the central region of the earth's geoid and is divided into two parts. The inner core is in the solid state, it is surrounded by the outer core, which is in the liquid phase. There is no clear boundary between the inner and outer cores; they are separated by a transition zone. The chemical composition of the core is judged by the density of the substance in it and on the basis of the assumption that the composition of the core is identical to the composition of iron meteorites. Therefore, the inner core is considered to consist of iron (80%) and nickel (20%). The corresponding alloy at the pressure of the earth's interior has a melting point of the order of 4,500 0 C. According to the same ideas, the outer core contains iron (52%) and eutectic (liquid mixture of solids) formed by iron and sulfur (48%). A small admixture of nickel cannot be ruled out. The melting point of such a mixture is estimated to be approximately 3200 0 C. In order for the inner core to remain solid and the outer core liquid, the temperature in the center of the earth should not exceed 4 500 0 C, but also not be lower than 3200 0 C. There are other estimates of the temperature in the center of the Earth, somewhat divergent from those given and of a speculative nature.
The liquid state of the outer core is associated with ideas about the nature of the earth's magnetism. The Earth's magnetic field is variable; the position of the magnetic poles changes from year to year. Paleomagnetic studies of the nature of the planet’s magnetic field in the distant past, based on measurements of the remanent magnetization of earth rocks, have shown that, for example, over the past 80 million years there has been not only a change in field strength, but also multiple systematic magnetization reversal, as a result of which the northern and The south magnetic poles switched places. During periods of polarity change, moments of complete disappearance of the magnetic field occurred. Consequently, terrestrial magnetism cannot be created by a permanent magnet due to the stationary magnetization of the core or some part of it. It is believed that the magnetic field is created by a process called the self-excited dynamo effect. The role of the rotor (moving element) of the dynamo can be played by the mass of the liquid core, moving as the Earth rotates around its axis, and the excitation system is formed by currents that create closed loops inside the sphere of the core.
The density and chemical composition of the mantle, according to seismic waves, differ sharply from the corresponding characteristics of the core. The mantle is formed by various silicates (compounds based on silicon). It is assumed that the composition of the lower mantle is similar to the composition of stony meteorites and chondrites.
The upper mantle is directly connected to the outermost layer - the crust. It is considered a kitchen where many of the rocks that make up the bark and their semi-finished products are prepared. The upper mantle is believed to consist of olivine (60%), pyroxene (30%) and feldspar (10%). In certain zones of this layer, partial melting of minerals occurs, and alkali basalts are formed - the basis of the oceanic crust. Through rift faults of the mid-ocean ridges, basalts come from the mantle to the Earth's surface. But this is not the only interaction between the crust and mantle. The brittle crust, which has a high degree of rigidity, together with part of the underlying mantle, forms a special layer about 100 km thick, called the lithosphere. This layer rests on the upper mantle, whose density is noticeably higher. The upper mantle has a feature that determines the nature of its interaction with the lithosphere: in relation to short-term loads it behaves as a rigid material, and in relation to long-term loads - as a plastic one. The lithosphere creates a constant load on the upper mantle and under its pressure the underlying layer, called the asthenosphere, exhibits plastic properties, the lithosphere “floats” in it. This effect is called isostasy.
The asthenosphere, in turn, rests on the deeper layers of the mantle, the density and viscosity of which increase with depth. The reason for this is the compression of rocks, causing a structural restructuring of some chemical compounds. The silicates that make up this modification of silicon have a very compact structure; they predominate in the lower mantle. In general, the lithosphere, asthenosphere and the rest of the mantle can be considered as a three-layer system, each part of which is mobile relative to the other components. The light lithosphere, based on a not too viscous and plastic asthenosphere, is particularly mobile.
The Earth's crust, which forms the upper part of the lithosphere, is mainly composed of eight chemical elements: oxygen, silicon, aluminum, iron, calcium, magnesium, sodium and potassium. Half of the total mass of the bark is oxygen, which is contained in it in bound states, mainly in the form of metal oxides. The geological features of the crust are determined by the combined effects of the atmosphere, hydrosphere and biosphere on it - these three outermost shells of the planet. The composition of the crust and outer shells is constantly updated, as illustrated by such data. Thanks to weathering and demolition, the substance of the continental surface is completely renewed in 80-100 million years. The loss of continental matter is compensated by secular uplifts of their crust. The vital activity of bacteria, plants and animals is accompanied by a complete change of carbon dioxide contained in the atmosphere in 6-7 years, oxygen - in 4000 years. The entire mass of water in the hydrosphere (1.4 * 10 18 tons) is completely renewed in 10 million years. An even more fundamental circulation of matter on the surface of the planet occurs in processes that connect all the internal shells into a single system.
There are stationary vertical flows called mantle jets, they rise from the lower mantle to the upper mantle and deliver hotter material there. Phenomena of the same nature include intraplate “hot fields”, which, in particular, are associated with the largest anomalies in the shape of the Earth’s geoid. In such places, elevations of the ocean surface by 50-70 m from the strict geoid line are observed. So the way of life in the interior of the earth is extremely complex. Deviations from mobilist positions do not undermine the idea of tectonic plates and their horizontal movements. But it is possible that in the near future a more general theory of the planet will appear, taking into account horizontal plate movements and open vertical transfers of hot matter in the mantle.
The uppermost shells of the Earth - the hydrosphere and atmosphere - are noticeably different from the other shells that form the solid body of the planet. By mass, this is a very small part of the globe, no more than 0.025% of its total mass. But the significance of these shells in the life of the planet is enormous. The hydrosphere and atmosphere arose at an early stage of the formation of the planet, and perhaps simultaneously with its formation. There is no doubt that the ocean and atmosphere existed 3.8 billion years ago.
The formation of the Earth followed a single process that caused the chemical differentiation of the interior and the emergence of the precursors of the modern hydrosphere and atmosphere. First, the Earth's proto-core formed from grains of heavy non-volatile substances, then it very quickly attached the substance that later became the mantle. And when the Earth reached approximately the size of Mars, the period of its bombardment by planetesimals began. The impacts were accompanied by strong local heating and melting of terrestrial rocks and planetesimals. At the same time, gases and water vapor contained in the rocks were released. And since the average surface temperature of the planet remained low, water vapor condensed, forming a growing hydrosphere. In these collisions, the Earth lost hydrogen and helium, but retained heavier gases. The content of isotopes of noble gases in the modern atmosphere allows us to judge the source that generated them. This isotopic composition is consistent with the hypothesis about the impact origin of gases and water, but contradicts the hypothesis about the process of gradual degassing of the earth's interior as the source of the formation of the hydrosphere and atmosphere. The ocean and atmosphere certainly existed not only throughout the history of the Earth as a formed planet, but also during the main accretion phase, when the proto-Earth was the size of Mars.
The idea of impact degassing, considered as the main mechanism for the formation of the hydrosphere and atmosphere, is gaining increasing recognition. Laboratory experiments confirmed the ability of impact processes to release noticeable amounts of gases, including molecular oxygen, from earth rocks. This means that some amount of oxygen was present in the Earth’s atmosphere even before the biosphere arose on it. Ideas about the abiogenic origin of some of the atmospheric oxygen were also put forward by other scientists.
Conclusion.
Both outer shells - the hydrosphere and the atmosphere - closely interact with each other and with the rest of the Earth's shells, especially with the lithosphere. They are directly influenced by the Sun and Space. Each of these shells is an open system that has a certain autonomy and its own internal laws of development. Everyone who studies the oceans of air or water is convinced that the objects of study exhibit an amazing subtlety of organization and the ability to self-regulate. But at the same time, none of the earth’s systems falls out of the general ensemble, and their joint existence demonstrates not just the sum of its parts, but a new quality.
Among the community of the Earth's shells, the biosphere occupies a special place. It covers the upper layer of the lithosphere, almost the entire hydrosphere and lower layers of the atmosphere. The term “biosphere” was introduced into science in 1875 by the Austrian geologist E. Suess (1831-1914). The biosphere was understood as the totality of living matter inhabiting the surface of the planet along with its habitat. A new meaning was given to this concept by V.I. Vernadsky, who considered the biosphere as a systemic formation, as the geological shell of the Earth. The significance of this system goes beyond the purely earthly world; it represents a link on a cosmic scale.
List of used literature:
1. Karpenkov S.Kh. Concepts of modern natural science: Textbook for universities. – M.: Culture and Sports, UNITY, 1997.
SECTION II
COSMOLOGICAL MODEL OF THE UNIVERSE (MEGAWORLD)
Chapter 1
UNIVERSE
The Universe is the entire existing material world, limitless in time and space, infinitely diverse in the forms that matter takes in the process of its development. Cosmology is the science of the Universe as a whole, its structure, origin and evolution. The Universe is a complex collection of celestial bodies; complex physical processes constantly occur in it. This makes the study of the Universe of great interest to modern natural science. In space it is possible to study states and changes of matter that are unattainable on Earth. Cosmology is based on physics, mathematics and philosophy. The part of the Universe covered by astronomical observations is called the Metagalaxy. The radius of the cosmic horizon is 15–20 billion light years.
Matter in the Universe is represented by condensed cosmic bodies (stars) and diffuse matter. Diffuse matter exists in the form of isolated atoms and molecules, as well as denser formations - giant clouds of dust and gas (gas-dust nebulae).
The entire space of the Universe is a physical vacuum that contains the entire material world and determines its existence based on the interaction of fields: weak, strong, gravitational and electromagnetic. They are the ones who control the movement and evolution of the material world, and are the sources of energy, movement, birth and death of objects in the material world.
Space is permeated by the movement and existence of various physical fields that determine the essence of the existence of matter. There is nothing in the Universe but space and time, our ancestors exclaimed. There is nothing in the Universe except physical vacuum, fields and matter united by motion, says modern physics.
Exploring the Universe
studies the stars astronomy(from the Greek “astron” - star and “nomos” - law) – the science of the structure and development of cosmic bodies and their systems. The main method of astronomical research is observation. As a result of observations, scientists receive over 90% of information about cosmic processes, phenomena and objects. Huge distances determine the only possible way to study the Universe, which consists in recording radiation. It should be taken into account that the signal recorded at a given moment on Earth is a characteristic of a process that took place in the radiation source several years or tens and even hundreds of years ago.
Currently, scientists have learned to detect the following types of radiation:
- light– radiation in the optical range, perceived by the human eye, wavelength about 10 -7 m;
- infrared radiation with a wavelength from 10 -6 m to 1 cm;
- microwave radiation(from 1 cm to 1 m);
- radio waves(from 1 m or more);
- ultraviolet radiation;
- X-ray radiation;
- gamma radiation;
- cosmic rays.
Depending on the nature of the radiation being studied, astronomy began to be divided into optical and radio astronomy, infrared, ultraviolet, x-ray and gamma astronomy. Astronomy is divided on celestial mechanics, radio astronomy, astrophysics and other disciplines.
First feature astronomical observations is that observations are passive and sometimes require very long periods. We cannot actively influence celestial bodies and conduct experiments with them. Only astronautics has provided some opportunities in this regard. Second feature astronomical research consists in the fact that we observe the position of celestial bodies and their movements from the Earth, which itself is in complex motion. The view of the sky for an earthly observer depends on where on Earth he is located and at what time he observes. For example, when we have a winter day, in South America it is a summer night, and vice versa.
Third feature astronomical observations is that during observations in many cases we make angular measurements and from them we draw conclusions about the linear distances and sizes of bodies. All the luminaries are so far from us that it is impossible to decide which of them either by eye or by telescope closer, which is further. They all seem equally distant. We say that two stars in the sky are close to each other if the directions in which we see them are close to each other.
Units of measurement in astronomy
Since nothing in nature can move faster than the speed of light, we can say that the size of the Universe does not exceed 2 C∙T, where C is the speed of light and T is the age of the Universe. Consequently, we can estimate the upper limit of the size of the Universe as 2 ∙ 3 ∙ 10 8 ∙ 15 ∙ 10 9 ∙ 365 ∙ 24 ∙ 60 ∙ 60 = 5.2 ∙ 10 26 m. This figure is so large that it is difficult to comprehend. For astronomical measurements, the meter is not a very suitable measure of length.
In astronomy, it is more convenient to measure distances in light years. A light year is the distance that light travels in an astronomical year, we can calculate this distance in meters: 1 light year = 3·10 8 ∙ 365 ∙24 ∙60 ∙60 = 9.46 ∙10 15 m.
Another unit convenient for astronomy is a quantity called parsec. Due to the movement of the Earth around the Sun, a star observed from Earth is visible from different angles at different times. The visible change in the position of a celestial body due to the movement of the observer is called parallax. There are parallax caused by the rotation of the Earth (diurnal parallax), the revolution of the Earth around the Sun (annual parallax) and the movement of the Solar system in the Galaxy (secular parallax). Parsec - (short for parallax and second) - an astronomical unit of measurement of stellar distances, equal to 3.26 light years. The farthest object discovered to date is a quasar at a distance of 8 billion light years from us. If we consider that the radius of the Universe is no more than 15 billion light years, then there is not much left to see the border itself.
In the solar system the basic unit of measurement is astronomical unit. This is the average distance from the Earth to the Sun, taken to be 150 million km.
Modern science has significantly expanded the possibilities of knowing the Universe; technical equipment has also increased significantly, which allows for a comprehensive study of outer space.
Study of meteorites. Meteorites are excellent material for studying the Universe, since their composition can be used to judge its substance. Research on meteorites has shown that they are composed of the same elements as the Earth. This fact serves as a clear confirmation of the unity of matter in the Universe.
The study of meteorites expands the boundaries of our knowledge about the internal structure of the Earth, since they are fragments of different parts of cosmic bodies. Meteorites carry very valuable information about the history of the origin of the planets of the solar system. According to nuclear chronology, their age, approximately 4.5-4.6 billion years, almost coincides with the age of the Earth.
Exploring outer space using telescopes and radio telescopes. Powerful telescopes make it possible to photograph space
celestial bodies and individual areas of the sky, in combination with various instruments, make it possible to determine the luminosity, temperature, relief of cosmic bodies, etc. Using telescopes, they study the spectra of luminaries, their changes, and based on the nature of the spectrum, they draw conclusions about the movement of cosmic bodies, their chemical composition substances, the type of reactions occurring on them. The use of radio telescopes has significantly expanded the possibilities of understanding the Universe.
Exploring outer space using artificial satellites, space stations and ships. This type of space exploration began on October 4, 1957, when the Soviet Union launched an artificial Earth satellite into low-Earth orbit for the first time in the world. On April 12, 1961, citizen of the Soviet Union Yu. Gagarin was the first to make a space flight around the Earth on the Vostok manned spacecraft. A few years later, Soviet cosmonaut A. Leonov first went into outer space.
In the Soviet Union, for the first time in world practice, the Luna-16 automatic spacecraft successfully flew to another celestial body and returned it to Earth. For a long time, the automatic apparatus “Lunokhod-1” operated on the Moon, which made it possible to establish the general type of rocks composing the surface of the lunar sea and to study the nature of the distribution of small craters and stones. As a result of the successful operation of the Luna-20 automatic station, the problem of taking soil from the hard-to-reach continental region of the Moon was solved.
With the help of Soviet automatic stations, valuable information was obtained about the atmosphere of Venus. For the first time, a soft landing of a spacecraft on the surface of Mars was carried out, and the Mars-2 and Mars-3 stations became artificial satellites of Mars. During their orbital flight, they transmitted a large amount of information about the physical features of the planet and the surrounding outer space.
Particularly valuable information was provided by lunar soil delivered to Earth by Soviet automatic stations and American cosmonauts. The surface material of the Moon bears the imprints of both the primary processes that led to the formation of the parent rocks and subsequent influences, many of which are absent on the Earth's surface. However, due to its characteristics, the Moon in many respects turned out to be “mothballed” for a long geological time, so we can expect that processes similar to those that occurred in the early stages of the formation of the Earth will be reflected on the Moon.
A new page in the study of Space and Earth was the unprecedented research of Soviet cosmonauts at space stations of the Salyut type. Photographing various regions of our country using multifocal cameras made it possible
make adjustments to tectonic zoning, identify promising areas for searching for minerals, study with the help of photographs the nature of grain ripening, the preservation of forest plantations, etc. Our cosmonauts conducted research on growing crystals characterized by unique properties; conducted experiments on soldering materials that are not amenable to this process under terrestrial conditions; conducted observations of the life activity of organisms in conditions of weightlessness; carried out astronomical observations using special devices, etc. Docking of transport ships with Salyut-6, refueling of its engines and timely correction of the orbit made it possible to create a prototype of a space station in orbit for the study of Space.
Hypothesis of the formation of planets in the solar system
For a long time, the problem of the formation of the Earth and the Solar system as a whole has attracted the attention of outstanding scientists. I. Kant, P. Laplace, D. Ginet, Soviet scientists - academicians O. Yu. Schmidt, V. G. Fesenkov, A. P. Vinogradov and others were involved in solving it. The hypotheses they proposed reflected the level of knowledge achieved by that time , however, a final solution to this problem has not yet been obtained. In the light of modern scientific achievements, the hypothesis of the formation of the Solar system comes down to the following.
Within our Galaxy, near its equatorial plane, there was an inhomogeneous gas-dust disk consisting of slowly rotating gas-dust clouds. The clouds consisted mainly of hydrogen atoms, due to an increase in the density of which their formation could occur. The density of hydrogen atoms in such a cloud reaches 1000 atoms/cm 3 , which is 10,000 times higher than their density in the normal interstellar space of the Galaxy. Along with hydrogen, the cloud could include carbon, nitrogen, oxygen, and micron-sized dust particles. Inside the clouds there is a chaotic, turbulent movement of matter.
As the size and density increase, the cloud begins to shrink under the influence of gravity. Gravitational compression of almost the entire mass of the initially cold cloud (-220 ° C) leads to its compaction to the state of the Proto-Sun. In the center of the latter, thermonuclear reactions become possible, accompanied by the release in the form of an explosion of a huge amount of energy and matter. According to academician A.P. Vinogradov, from the substance ejected about 5.5 billion years ago by explosions around the Protosun, a hot plasma cloud (protoplanetary cloud) was formed. At the first stage of planet formation, the protoplanetary cloud cooled, gases were lost into outer space, and part of its matter condensed into solid particles. The most refractory chemical elements condensed first: 10
tungsten, titanium, molybdenum, platinum, etc., as well as their oxides. Thus, the hot gaseous substance again turned into a cold gas-dust cloud. The protoplanetary cloud lost energy over time as a result of the collision of “dust grains.” Its flattening occurred, the movement of matter in it was ordered, and became close to circular. Gradually, around the young Sun, as a result of the condensation of dusty matter, a wide annular disk formed, which broke up into separate cold groups of matter - swarms of solid gas particles. They interacted with each other, mixed, collided, fused, and were exposed to cosmic irradiation. The formation of separate phases of matter occurred, mainly silicates, iron-nickel metal alloy, sulfides, etc. As a result of the agglomeration of these phases, stone and other meteorites arose. The same process of contraction of the cold matter of the protoplanetary cloud led to the formation of the protoplanets of the Solar System about 5 billion years ago. Having formed as a geological body, the Proto-Earth had not yet become a planet. It was a cold accumulation of cosmic matter, but it was from this time that its pre-geological evolution began.
Under the influence of such factors as impacts of meteorite bodies, gravitational compaction and the release of heat by radioactive elements, the upper parts of the Proto-Earth began to warm up. Iron was melted first, then silicates. This led to the emergence of a belt of liquid iron here. Due to the differentiation of the substance, the lighter silicate material should have floated to the top, and the heavy metal should have concentrated in the center of the planet. Viscous, predominantly silicate masses formed the primary mantle of the Earth, and metallic masses formed its core. This is how, apparently, planet Earth was formed about 4.6 billion years ago.
The inner planets, located closer to the Sun, were formed by the condensation of a high-temperature fraction rich in iron. The further away from the Sun the planets have less metallic material. Thus, Mercury consists of 2/3 of metallic iron, and Mars - 1/4. In the asteroid ring, predominantly chondritic asteroids were formed, in which the content of the low-temperature fraction increased. And, finally, the main component of the outer planets are gases, almost entirely consisting from undivided solar matter.