Located in the center of its own solar system. Eight planets revolve around it, one of which is our home, the planet Earth. The sun is the star on which our life and existence directly depends, because without it, we would not even have been born. And if the Sun disappears (as our scientists still predict, this will happen in the distant future, in a few billion years), then humanity, and the entire planet as a whole, will have a very hard time. That is why it is currently the most important star for us. One of the most intriguing and interesting topics associated with space is the structure and evolution of the Sun. It is this question that we will consider in this article.

How was this star born?

The evolution of the Sun is a very important issue for our life. It appeared much earlier than Earth. Scientists suggest that now it is in the middle of its life cycle, that is, this star is already about four or five billion years old, which is very, very long. The origin and evolution of the Sun are closely intertwined, because the birth of a star plays an important role in its development.

Speaking very briefly, the Sun was formed from a large accumulation of gas clouds, dust and various substances. Substances kept accumulating and accumulating, as a result of which the center of this accumulation began to acquire its own mass and gravity. It then spread throughout the nebula. Things have come to the point that the middle of this whole mass, consisting of hydrogen, acquires density and begins to draw in gas clouds and dust particles flying around. Then there was a thermonuclear reaction, thanks to which our Sun lit up. So, gradually growing, this substance was transformed into what we now call a star.

At the moment, it is one of the main sources of life on Earth. If only its temperature increased by a few percent, then we would no longer exist. It was thanks to the Sun that our planet was born and had ideal conditions for further development.

Characteristics and composition of the Sun

The structure and evolution of the Sun are interconnected. It is by its structure and several other factors that scientists determine what will happen to it in the future and how it can affect humanity, animals and vegetable world our planet. Let's find out a little about this star.

Previously, it was believed that the Sun is an ordinary yellow dwarf, representing nothing. But later it turned out that it contains many chemical elements, and very massive. If you describe in detail what our star consists of, you can spend a whole article on it, so I can only mention it briefly.

Hydrogen and helium play the most significant part in the composition of the Sun. It also contains many other substances, for example, iron with oxygen, nickel and nitrogen, and many others, but they account for only 2% of the composition.

The surface covering of this star is called the corona. It is very thin, so that it is almost invisible (except when the Sun is getting dark). The crown has an uneven surface. In this regard, it is covered with holes. It is through these holes that the solar wind seeps at great speed. Under the thin shell is the chromosphere, which is stretched in thickness for 16 thousand kilometers. It is in this part of the star that various chemical and physical reactions. The famous solar wind is immediately formed - an influx of a whirlwind of energy, which is often the cause of various processes on Earth (aurora borealis and magnetic storms). And the most powerful storms of fire occur in the photosphere - a dense and non-translucent layer. The main task of the gases in this part is the consumption of energy and light from the lower layers. The temperature here reaches six thousand degrees. The place of gas energy exchange is in the convective zone. From here, gases rise into the photosphere, and then return back to obtain the necessary energy. And in the boiler (the lowest layer of the star) there are very important and complex processes associated with proton thermonuclear reactions. It is from here that the entire Sun receives its energy.

Sun evolution sequence

So we come to the most important issue of our article. The evolution of the sun is the changes that occur to the star in the course of its life: from birth to death. We have previously discussed why it is important for people to be aware of this process. Now we will analyze several stages of the evolution of the Sun in order.

In one billion years

The temperature of the sun is predicted to rise by one ten percent. In this regard, all life on our planet will die out. So it remains to be hoped that people will master other galaxies by this time. It is also possible that some life in the ocean may still have a chance to exist. There will come a period of the maximum temperature of a star in its entire life.

Three and a half billion years later

The brightness of the Sun will almost double. In this regard, there will be a complete evaporation and volatilization of water into space, after which any earthly life will not have a chance to exist. The earth will become like Venus. Further, in the process of evolution of the Sun, its energy source will gradually burn out, the cover will expand, and the core, on the contrary, will begin to decrease.

In six and a half billion years

At the central point of the sun, where the energy source is located, the hydrogen reserves will be completely depleted, and helium will begin its own contraction due to the fact that it cannot exist in such conditions. Particles of hydrogen continue to burn out only in the corona of the Sun. The star itself will begin to turn into a supergiant, increasing in volume and size. The brightness will gradually increase along with the temperature, resulting in even more expansion.

In eight billion years (the extreme stage of the development of the Sun)

The burning of hydrogen will start throughout the star. This is when her core heats up very, very strongly. The sun will completely leave its orbit in the process of expansion from all of the above processes and will have the right to be called a red giant. At this moment, the radius of the star will grow by more than 200 times, and its surface will cool. The Earth will not be swallowed up by the inflamed Sun and will depart from its orbit. Later it can be absorbed. But if this does not happen, then all the same, all the water on the planet will go into a gaseous state and evaporate, and the atmosphere will still be absorbed by the strongest solar wind.

Outcome

As mentioned earlier, the evolution of the Sun will greatly affect our life and the existence of the planet as a whole. As it is not very difficult to guess, in any case it will be very bad for the Earth. After all, as a result of its evolution, the star will destroy the entire civilization, and possibly even swallow our planet.

It was easy to draw such conclusions, because people already knew that the Sun is a star. The evolution of the Sun and stars of the same size and type proceeds in a similar way. On the basis of this, these theories were built, and also confirmed by the facts. Death is an integral part of the life of any star. And if humanity wants to survive, then in the future we will have to put all our efforts into leaving our planet and avoiding its fate.

The evolution of our Sun to the stage of a red giant will lead to the fact that it will first burn the Earth due to the huge amount of energy released, and then, as a result of expansion, absorb its remains. According to the calculations of astronomers, about 5 billion years will pass until this moment.

The residence time of an ordinary star in the red giant stage is about 10 7 years. Having reached its maximum size at this stage, the star quickly shifts to the left in the luminosity-color diagram. During this period, the balance of most stars is disturbed, and they begin to pulsate, changing their luminosity. Further evolution proceeds depending on the mass of the star. If it is less than 1.4 solar masses (a "light" star), then, having used up nuclear fuel, it cools down and eventually fades away. In this case, it passes through the stage of instability, during which there is a periodic increase in luminosity. A sharp increase in luminosity is recorded as the birth new stars. Then the stage of the "new" star passes into the stage white dwarf, then, after further cooling, to the stage red dwarf, and finally in black dwarf.

The evolution of a star with a mass greater than 1.4 solar masses ends in a spectacular explosion, and this is considered the birth in excess of new star. After a supernova explosion, high pressures and temperatures arise, and conditions are created for the formation of neutrons. Since there is no electrostatic repulsion for neutrons, neutron matter collapses under the influence of gravity, forming a small superdense ball. The density in it is so high that neutron decay is forbidden. Such stellar bodies are called neutron stars.

In 1968, objects were discovered that are a source of variable radio emission with a pulsation frequency of about 1 Hz. They got the name pulsars. Gold proposed a model according to which a pulsar is a rotating neutron star. The lifetime of a pulsar is 10 8 years.

In the early 1960s, radio sources associated with blue-colored objects resembling stars were discovered. They were called quasi-stars, or quasars. The origin and structure of quasars is currently unclear. However, it has been established that they are characterized by a strong redshift, therefore it can be assumed that quasars are the most distant and fastest moving objects in the universe.

According to modern concepts, up to 90% of the matter in the Universe is in an unknown state, i.e. there is a mass "hidden" from the observer. American physicist Wheeler in 1969 proposed the term black hole for a space object with hidden mass. A black hole results from the compression of a space object if its mass exceeds the mass of the Sun by three times. The compression of such an object cannot be prevented by any forces, and the star turns into a black hole with a radius of about 3 km. At the boundary of a black hole, the second cosmic velocity required to move away from a given cosmic body is equal to the speed of light. This means that no natural phenomenon or interaction can go beyond the black hole. It has such a large gravitational field that even EM radiation cannot leave it.

The existence of a black hole can be described in terms of general relativity, which allows for any object with a mass to calculate the so-called. gravity radius , or the radius of the Schwrtzschild sphere, who was the first to solve Einstein's equation for a spherically symmetric mass distribution. So, the gravitational radius of the Sun is about 3 km, and for the Earth - about 1 cm.

The presence of a strong gravitational field in a black hole leads to the fact that time flows more and more slowly as it approaches the black hole. At a distance of a gravitational radius, time completely stops from the point of view of a distant observer, i.e. Black holes bend space and slow down time. In this sense, the GR considers the black hole as a "graveyard" of everything that it managed to capture.

In 1975, S. Hawking showed that the gravitational field near the surface of a black hole gives rise to pairs of particles from vacuum, one of which is captured by the black hole, and the other flies into the surrounding space, i.e. it turns out that a black hole can emit particles different types, i.e. The black hole is gradually dissipating in outer space. This is how matter cycles in the universe. The annihilation of particles and antiparticles leads to powerful? radiation, which can be used to detect black holes. It is assumed that at the center of the Galaxy there is a black hole with a mass of 10 6 solar masses.

The evolution of the solar system.

Quite a lot is known about the solar system from astronomical observations, astrophysical research, from information collected by spacecraft, as well as from the study of cosmic radiation and meteorites falling on the Earth.

The solar system includes the central body (the Sun), a group of planets closest to it (Mercury, Venus, Earth, Mars), an asteroid belt of tens of thousands of more distant small planets (asteroids), a group of outer planets (Jupiter, Saturn, Uranus, Neptune ), Pluto, which was recently recognized not as a planet, but as an asteroid, about 90 satellites of the planets, an indefinite number of comets and the interstellar medium in the form of plasma, cosmic dust, EM radiation and elementary particle flows. In addition, about 70 extrasolar planets have been discovered, which belong to other systems that differ significantly from each other.

Our Sun- a typical G-2 dwarf star is a luminous ball of gas that does not have a clear boundary, its density decreases gradually, but thanks to the photosphere, the illusion is created that the Sun has a surface. Chemical composition: 90% hydrogen, 10% helium, other elements - less than 0.1% (by number of atoms). The source of solar energy is thermonuclear reactions. The energy of their bowels is carried by radiation, and in the thin outer layer- convection. The existence of the so-called convective motion is connected with the convective motion. sun spots.

Regular observations of spots on the Sun have been conducted since 1610 - the invention of the telescope. 11-year cycles of solar activity are known. The periods of high and low solar activity coincide with changes in the earth's climate. During the entire period covered by the research, the Sun has never been as active as it has been over the past 60 years.

Most of the light flux of the Sun is emitted by the photosphere in the form of EM radiation in the visible and infrared range. Above the photosphere is the corona of the Sun - the most unstable shell of the Sun. Hot plasma flowing from the corona forms the solar wind - a stream of ions (90% - protons, 4% - alpha particles) and electrons. The speed of the solar wind is 800-900 km/s. The solar wind and magnetic field fill the entire solar system. The Earth and other planets are actually in the corona of the Sun.

There are well-developed mathematical theories describing the motion of the bodies of the solar system (space mechanics). At present, the most studied are cosmic radiation and meteorites falling on the Earth, the Earth itself and its satellite, the Moon. The total mass of the planets is approximately 1/743 of the mass of the Sun. The orbits of the planets lie approximately in the same plane. All planets except Venus rotate from west to east, Venus rotates in the opposite direction. The planets differ markedly in composition: the giant outer planets contain more hydrogen, helium, water, methane, while the inner planets contain more heavy elements. As a rule, as you move away from the Sun, the content of the components decreases in the following order: Fe, Ni ? O, Si, Mg? H 2 O, CH 4 . The composition of meteorites reflects the composition of other bodies in the solar system. About 100 different minerals have been found in meteorites, 80 of which are found on Earth. Stony meteorites predominate.

First scientific concepts The emergence and evolution of the Earth arose about 250 years ago. The first hypothesis is associated with a catastrophic, simultaneous ejection of matter from the Sun with the formation of planets, associated with a critical approach of the Sun and a large comet (J.L. Buffon, 17th century). The second concept involves the long-term formation of the solar system due to the process of condensation of a rarefied space medium under the influence of gravitational forces (the hypothesis of I. Kant and M. Laplace, 18th century). Modern cosmogonic theory adheres to the second version.

The presence of heavy elements in the composition of the bodies of the Solar System, in addition to hydrogen and helium, indicates that the protoplanetary medium arose, at least in part, as a result of a supernova explosion. The primary nebula, participating in the general rotation with the Galaxy, has a certain rotational moment, which prevents it from being compressed to a high density in a single center. Calculations have shown that under certain conditions of rotation, fragments of the primary nebula can shrink to form single stable stars like the Sun. During the evolution of each such star, a gas and dust disk is formed around it. In about 10 6 years, the center of the disk turns into a relatively slowly rotating Sun with a mass of ?2 10 30 kg, and the rapidly rotating outer part of the disk later turns into a system of planets, their satellites, and asteroids with a total mass of ?0.1 of the Sun's mass. The proximity of the composition of the bodies of the solar system, the movement of these bodies in similar orbits indicates the commonality of the formation of the entire solar system.

Asteroids and comets are the remains of a swarm of pre-planetary bodies. The largest asteroids (> 100 km) were formed even before the formation of the planets, while small and medium ones were formed during the collision and destruction of large ones. The origin of comets is associated with the influence of nearby stars on the most distant small bodies of the planetary system, which further displaced these bodies and stretched their orbits.

The system of satellites of the planets was formed in approximately the same way as the planetary system as a whole. The exception is satellites rotating in the opposite direction. There are very few such satellites, only Jupiter, Saturn and Neptune have them. Their origin is associated with the capture by the planets of small celestial bodies flying nearby. This capture process allowed the Sun and planets to fairly well clear the Solar System of small bodies and cosmic dust. Thus, the Earth every day captures approximately 260,000 tons of meteorite material.

Using the example of the formation of the Solar System, one can see how a many-particle completely chaotic system gradually turned into a deterministic system of cosmic macro-bodies, the motion of which is very accurately described classical mechanics. The sun, planets and their satellites, asteroids and comets form a single self-organizing system in which, under certain conditions, realized on at least one planet, intelligent life arose.

Sunny wind- a stream of ionized particles (mainly helium-hydrogen plasma) flowing out of solar corona at a speed of 300-1200 km / s into the surrounding outer space.

Lots of natural phenomena associated with the solar wind, including magnetic storms and auroras.

In relation to other stars, the term stellar wind is used, so that in relation to the solar wind one can say "stellar wind of the Sun."

Introduction

sun star eclipse

The sun plays an exceptional role in the life of the Earth. The entire organic world of our planet owes its existence to the Sun. The sun is not only a source of light and heat, but also the original source of many other types of energy (energy of oil, coal, water, wind).

Since ancient times, the sun has been an object of worship among different peoples. He was considered the most powerful deity. The cult of the invincible Sun was one of the most widespread (Helios - the Greek god of the Sun, Apollo - the god of the Sun among the Romans, Mitra - among the Persians, Yarilo - among the Slavs, etc.). Temples were erected in honor of the Sun, hymns were composed, and sacrifices were made. Gone is the religious worship of the daylight. Now scientists are investigating the nature of the Sun, finding out its influence on the Earth, and working on the problem of using the almost inexhaustible solar energy.

The sun is our star. By studying the Sun, we learn about many phenomena and processes that occur on other stars and are inaccessible to direct observation due to the huge distances that separate us from the stars.

Evolution of the Sun and Solar System

The age of the Sun is approximately 4.5 billion years. Since its birth, it has used up half of the hydrogen contained in the core. It will continue to radiate "peacefully" for the next 5 billion years or so (although its luminosity will roughly double over that time). But in the end, it will run out of hydrogen fuel, which will lead to drastic changes, which is common for stars, but alas, will lead to the complete destruction of the Earth (and the creation of a planetary nebula).

Sun evolution:

A. On the Sun, nuclear reactions begin to take place in the core. This is called the birth of a star, before the start of nuclear reactions, the object is called a protostar, and the temperature in the core is still too low for nuclear combustion to begin.

B. By this time, about half of the hydrogen in the core will have been converted to helium. This is the situation in which the Sun is now (approximately 4.5 billion years have passed since the birth of the Sun).

C. The hydrogen in the core is almost completely recycled, and the combustion of hydrogen begins in a layered source around the core. This causes the Sun to swell. Its radius becomes about 40% larger, and its luminosity doubles.

D. In one and a half billion years, the surface of the Sun will be 3.3 times larger than it is now, and the temperature will drop to 4300 degrees Kelvin. When viewed from the Earth, the Sun will look like a large orange ball. However, the main problem is that the temperature of the Earth will rise by 100 degrees and all the seas will evaporate, so there will be no observers of this grandiose picture. In the next 250 million years, the radius of the Sun will increase by a factor of 100, and its luminosity will increase by more than 500 times. It will take up almost half the sky on a planet that was once Earth.

E. The temperature of the core will rise so high that the reaction of converting helium into carbon will begin to proceed. Perhaps this process will be explosive and one third of the solar shell will be dispersed in space.

What happens after that is currently unknown. The sun will become brighter, and all the outer layers will be blown into space by a very strong solar wind. This phenomenon is called the formation of a planetary nebula; examples of such objects are often observed in space (there is always a star inside a planetary nebula that gave birth to it).

After that, practically only the core of the former Sun, the so-called white dwarf, which has a mass half that of the modern Sun, but with an abnormally high density of matter: 2 tons per cubic centimeter. This white dwarf will slowly cool down, turn into a black dwarf, and this will be the end of the Sun.

1 option

1. The mass of the Sun is ... from the mass of the entire solar system.

a) 99.9%; b) 39.866%; c) 32.31%; d) 27.46%.

2. The average diameter of the Sun is ... diameters of the Earth.

a) 313; b) 109; c) 198; d) 998.

3. The period of rotation of the Sun at the equator is ...

4. The amount of energy passing through a 1m 2 area perpendicular to the sun's rays in 1 s is called ...

5. The sun consists of ... hydrogen.

6. Stefan-Boltzmann law - ....

a) b) ; c) d).

7. With an increase in the number of spots on the Sun, the brilliance of a star ...

a) is increasing b) decreases; c) does not change; d) fluctuates periodically.

8. The flow of ionizing particles flowing from the solar corona into the surrounding space is called ...

9. Heavenly body, revolving around a star, having a spherical shape, under the influence of its own gravity, and removing small bodies from an orbit close to its own, is called ...

a) a planet b) an asteroid; c) a comet; d) meteorite.

10. The angle at which one could see the semi-major axis of the earth's orbit from a star is called ...

a) angular distance; b) stellar parallax;

c) annual parallax; d) perpendicular parallax.

11. The total energy radiated by a star per unit time is called ...

12. The dominant color in the spectrum of a star depends on ... the star.

a) masses; b) buildings; c) age; d) temperature.

13. In the center of the star is ...

a) convection zone; b) radiant energy transfer zone;

c) zone thermonuclear reactions; d) atmosphere.

14. Stars in ellipses, rotating around a common center of mass, are called ...

15. Stars that change their luminosity as a result of physical processes occurring in a star are called ...

16. A star that increases its brightness thousands and millions of times in a few hours, and then dims, is called ...

a) new; b) supernova; c) Cepheid; d) pulsating.

17. The minimum cloud size in which spontaneous compression can begin is determined by ...

a) Newton b) Hubble; c) Win; d) Jeans.

18. When all the nuclear fuel inside the star burns out, the process begins ...

a) gradual expansion; b) gravitational compression;

c) the formation of a protostar; d) star pulsations.

19. If the mass of a star

20. Our Galaxy is called…

Sun. Stars. The structure and evolution of the universe

Option 2

1. The mass of the Sun is ... masses of the Earth.

a) 392109; b) 332982; c) 139209; d) 99866.

2. Average diameter of the Sun…

a) 99.866 10 9 m; b) 1.392 109 m; c) 3.131 109 m; d) 2.745 10 9 m.

3. The period of rotation of the Sun at the pole is ...

a) 52.05 days; b) 43.3 days; c) 25.05 days; d) 34.3 days.

4. Energy radiated by the Sun in 1 s. from the entire surface, is called ...

a) the solar constant; b) the luminosity of the Sun;

c) solar energy; d) thermonuclear reaction.

5. The sun consists of ... of helium.

a) 27%; b) 2%; c) 72%; d) 71%.

6. Wine's Law - ....

a) b) ; c) d).

7. The age of the Sun is (approximately):

a) 5 billion years; b) 15 billion years; c) 100 billion years; d) 25 billion years.

8. Dense condensations of relatively cold matter that rise and are held above the surface of the Sun are called ...

a) flash; b) solar wind; c) prominence; d) a torch.

9. A spatially isolated, gravitationally bound, opaque object for radiation, in which thermonuclear reactions occur, is called ...

a) a planet b) an asteroid; c) a comet; d) a star.

10. The distance to a star can be determined by the formula ...

a) b); c) d)

11. The magnitude that a star would have if it were at a distance of 10 pc from us is called ...

a) apparent stellar magnitude; b) absolute magnitude;

c) luminosity; c) stellar constant.

12. The sun belongs to the spectral class ..

a) B; b) F; c) G; d) M.

13. The transfer of energy to the surface of stars passes through ..

a) convection zone; b) radiant energy transfer zone;

c) zone of thermonuclear reactions; d) atmosphere.

14. Stars, the brightness of which changes, are called ...

a) double; b) variables; c) stationary; d) non-stationary.

15. Pulsating stars of high luminosity are called ...

a) Cepheids; b) physically variable;

c) eclipsing variables; d) spectral variables.

16. Stars that suddenly explode and reach a maximum absolute magnitude from -11 m to -21 m are called ...

a) new; b) supernovae; c) Cepheids; d) pulsating.

17. Giant molecular clouds with masses greater than 105 solar masses are called ...

a) pulsars; b) nebulae; c) galaxies; d) regions of star formation.

18. In a stationary state, the star on the Hertzsprung-Russell diagram is on ...

a) the main sequence; b) into a sequence of supergiants;

c) into a sequence of subdwarfs;

d) into a sequence of white dwarfs.

19. If the mass of a star is 1.4 solar masses, when the nuclear fuel burns out, the star turns into ...

a) a white dwarf b) red giant; in) neutron star; d) a black hole.

20. The nearest galaxy to us is called ...

a) Sombrero; b) the Andromeda nebula;

in) Milky Way; d) Horse head.

Answers to test № 2

1 option

Option 2