What is the sun? brief description. Sun - astronomical information

The sun is the central body solar system, a hot plasma ball, a typical dwarf star of spectral class G2:

• mass M~2·10 30 kg
• radius R=696 t. km,
• average density 1.416 10 3 kg/m 3
• luminosity L=3.86·10 23 kW
• effective surface temperature (photosphere) about 6000 K

The rotation period (synodic) varies from 27 days at the equator to 32 days at the poles, the acceleration of gravity is 274 m/s 2 . Chemical composition determined from analysis of the solar spectrum: hydrogen - about 90%, helium - 10%, other elements - less than 0.1% (by number of atoms). The source of solar energy is the nuclear transformation of hydrogen into helium in the central region of the Sun, where the temperature is 15 million K. Energy from the interior is transferred by radiation, and then in the outer layer about 0.2 R thick - by convection.

To get to know internal structure Sun, let us now take an imaginary journey from the center of the star to its surface. But how will we determine the temperature and density of the solar globe at different depths? How can we find out what processes take place inside the Sun?

It turns out that most of the physical parameters of stars (our Sun is also a star!) are not measured, but are calculated theoretically using computers. The starting points for such calculations are only a few General characteristics stars, for example, its mass, radius, as well as the physical conditions prevailing on its surface: temperature, extent and density of the atmosphere, and the like. The chemical composition of a star (in particular, the Sun) is determined spectrally. And based on these data, a theoretical astrophysicist creates a mathematical model of the Sun. If such a model corresponds to the observational results, then it can be considered a fairly good approximation to reality. And we, relying on such a model, will try to imagine all the exotic depths of the great star.

The central part of the Sun is called its core. The matter inside the solar core is extremely compressed. Its radius is approximately 1/4 the radius of the Sun, and its volume is 1/45 (a little more than 2%) of the total volume of the Sun. Nevertheless, almost half of the solar mass is packed into the core of the star. This became possible due to the very high degree of ionization of solar matter. The conditions there are exactly the same as those needed for a thermonuclear reactor to operate. The core is a giant controlled power station where solar energy is generated.

Having moved from the center of the Sun to approximately 1/4 of its radius, we enter the so-called radiation energy transfer zone. This most extensive inner region of the Sun can be imagined as like the walls of a nuclear boiler, through which solar energy slowly leaks out. But the closer to the surface of the Sun, the lower the temperature and pressure. As a result, vortex mixing of the substance occurs and energy transfer occurs predominantly by the substance itself. This method of energy transfer is called convection, and the subsurface layer of the Sun where it occurs is called the convective zone. Solar researchers believe that its role in the physics of solar processes is exceptionally great. After all, it is here that various movements of solar matter and magnetic fields originate.

Finally we are at the visible surface of the Sun. Since our Sun is a star, a hot plasma ball, it, unlike the Earth, Moon, Mars and similar planets, cannot have a real surface, understood in the full sense of the word. And if we are talking about the surface of the Sun, then this concept is conditional.

The visible luminous surface of the Sun, located directly above the convective zone, is called the photosphere, which is translated from Greek as “sphere of light.”

The photosphere is a 300-kilometer layer. This is where solar radiation comes to us. And when we look at the Sun from Earth, the photosphere is precisely the layer that penetrates our vision. Radiation from deeper layers no longer reaches us, and it is impossible to see them.

The temperature in the photosphere increases with depth and is estimated on average at 5800 K.

The bulk of the optical (visible) radiation of the Sun comes from the photosphere. Here, the average gas density is less than 1/1000 the density of the air we breathe, and the temperature decreases to 4800 K as we approach the outer edge of the photosphere. Hydrogen under such conditions remains almost completely neutral.

Astrophysicists take the base of the photosphere as the surface of the great star. They consider the photosphere itself to be the lowest (inner) layer of the solar atmosphere. Above it are two more layers that form the outer layers of the solar atmosphere - the chromosphere and the corona. And although there are no sharp boundaries between these three layers, let’s get acquainted with their main distinguishing features.

The yellow-white light of the photosphere has a continuous spectrum, that is, it looks like a continuous rainbow stripe with a gradual transition of colors from red to violet. But in the lower layers of the rarefied chromosphere, in the region of the so-called temperature minimum, where the temperature drops to 4200 K, sunlight experiences absorption, due to which narrow absorption lines are formed in the solar spectrum. They are called Fraunhofer lines, named after the German optician Joseph Fraunhofer, who carefully measured the wavelengths of 754 lines in 1816.

To date, over 26 thousand dark lines of varying intensity have been recorded in the spectrum of the Sun, arising due to the absorption of light by “cold” atoms. And since each chemical element has its own characteristic set of absorption lines, this makes it possible to determine its presence in the outer layers of the solar atmosphere.

The chemical composition of the Sun's atmosphere is similar to that of most stars formed within the last few billion years (called second-generation stars). Compared to old celestial bodies (stars of the first generation), they contain tens of times more heavy elements, that is, elements that are heavier than helium. Astrophysicists believe that heavy elements first appeared as a result of nuclear reactions that occurred during the explosions of stars, and perhaps even during the explosions of galaxies. During the formation of the Sun, the interstellar medium was already quite well enriched in heavy elements (the Sun itself does not yet produce elements heavier than helium). But our Earth and other planets condensed, apparently, from the same gas and dust cloud as the Sun. Therefore, it is possible that, studying chemical composition our daylight star, we are also studying the composition of the primary protoplanetary matter.

Since the temperature in the solar atmosphere varies with altitude, absorption lines at different levels are created by atoms of different chemical elements. This makes it possible to study the various atmospheric layers of the great star and determine their extent.

Above the photosphere there is a thinner layer of the Sun's atmosphere called chromosphere, which means "painted sphere". Its brightness is many times less than the brightness of the photosphere, so the chromosphere is visible only during short minutes of total solar eclipses, like a pink ring around the dark disk of the Moon. The reddish color of the chromosphere is caused by hydrogen radiation. This gas has the most intense spectral line - H - is in the red region of the spectrum, and there is especially a lot of hydrogen in the chromosphere.

From spectra obtained during solar eclipses, it is clear that the red line of hydrogen disappears at an altitude of approximately 12 thousand km above the photosphere, and the lines of ionized calcium cease to be visible at an altitude of 14 thousand km. This height is considered as the upper boundary of the chromosphere. As the temperature rises, the temperature increases, reaching 50,000 K in the upper layers of the chromosphere. With increasing temperature, the ionization of hydrogen and then helium increases.

The increase in temperature in the chromosphere is quite understandable. As is known, the density of the solar atmosphere quickly decreases with height, and a rarefied medium emits less energy than a dense one. Therefore, the energy coming from the Sun heats up the upper chromosphere and the corona lying above it.

Currently, heliophysicists using special instruments observe the chromosphere not only during solar eclipses, but also on any clear day. During a total solar eclipse, you can see the outermost layer of the solar atmosphere - the corona - a delicate pearly-silver glow extending around the eclipsed Sun. The total brightness of the corona is about one millionth the light of the Sun or half the light of the full Moon.

The solar corona is a highly rarefied plasma with a temperature close to 2 million K. The density of coronal matter is hundreds of billions of times less than the density of air near the Earth's surface. Under such conditions, atoms of chemical elements cannot be in a neutral state: their speed is so high that during mutual collisions they lose almost all their electrons and are repeatedly ionized. This is why the solar corona consists mainly of protons (hydrogen atomic nuclei), helium nuclei and free electrons.

The exceptionally high temperature of the corona causes its material to become a powerful source of ultraviolet and X-ray radiation. For observations in these ranges of the electromagnetic spectrum, as is known, special ultraviolet and X-ray telescopes installed on spacecraft and orbital scientific stations are used.

Using radio methods (the solar corona intensely emits decimeter and meter radio waves), coronal rays are “viewed” up to distances of 30 solar radii from the edge of the solar disk. With distance from the Sun, the density of the corona decreases very slowly, and its uppermost layer flows into outer space. This is how the solar wind is formed.

Only due to the volatilization of corpuscles, the mass of the Sun decreases every second by no less than 400 thousand tons.

The solar wind blows across the entire space of our planetary system. Its initial speed reaches more than 1000 km/s, but then it slowly decreases. The Earth's orbit has an average wind speed of about 400 km/s. It sweeps away in its path all the gases emitted by planets and comets, the smallest meteor dust particles and even particles of galactic cosmic rays low energies, carrying all this “garbage” to the outskirts of the planetary system. Figuratively speaking, we seem to be bathing in the crown of a great star...

– the only star in the solar system: description and characteristics with photos, Interesting Facts, composition and structure, location in the galaxy, development.

The sun is the center and source of life for our solar system. The star belongs to the class of yellow dwarfs and occupies 99.86% of the total mass of our system, and its gravity prevails over all celestial bodies. In ancient times, people immediately understood the importance of the Sun for earthly life, which is why mention of a bright star is found in the very first texts and rock paintings. It was the central deity ruling over all.

Let's study the most interesting facts about the Sun - the only star in the solar system.

A million Earths can fit inside

• If we fill our star, the Sun, 960,000 Earths will fit inside. But if they are compressed and deprived of free space, the number will increase to 1,300,000. The surface area of ​​the Sun is 11,990 times larger than that of the Earth.

Holds 99.86% of system weight

• Its mass is 330,000 times greater than that of Earth. Approximately ¾ is allocated to hydrogen, and the rest to helium.

Almost perfect sphere

• The difference between the equatorial and polar diameters of the Sun is only 10 km. This means that we have before us one of the celestial bodies closest to the sphere.

Temperatures in the center rise to 15 million °C

• In the core, heat is created due to the fusion process where hydrogen is transformed into helium. Hot objects usually expand, so our star might explode but is held together by powerful gravity. The surface temperature rises to 5600 °C.

One day the sun will engulf the earth

• When the Sun uses up its entire hydrogen supply (130 million years), it will switch to helium. This will cause it to increase in size and absorb the first three planets. This is the red giant stage.

One day it will reach earth size

• After the red giant, it will collapse and leave a compressed mass in an Earth-sized ball. This is the white dwarf stage.

A ray of sunshine reaches us in 8 minutes

• The Earth is 150 million km away from the Sun. The speed of light is 300,000 km/s, so the beam takes 8 minutes and 20 seconds to travel to us. But it is also important to understand that it took millions of years for the energy to move from the solar core to the surface.

The speed of the Sun is 220 km/s

• The Sun is 24,000-26,000 light years away from the galactic center. Therefore, it spends 225-250 million years on its orbital path.

The Earth-Sun distance changes throughout the year

• The Earth moves along an elliptical orbital path, so the distance is 147-152 million km (astronomical unit).

This is a middle aged star

• The Sun is 4.5 billion years old, which means it has already burned through about half of its hydrogen reserves. But the process will continue for another 5 billion years.

A powerful magnetic field is observed

• Solar flares occur during magnetic storms. We see this as the formation of sunspots, where magnetic lines twist and spin like terrestrial tornadoes.

The star generates the solar wind

• The solar wind is a stream of charged particles passing through the entire solar system at an acceleration of 450 km/s. Wind appears where the Sun's magnetic field extends.

Name of the Sun

• The word itself comes from Old English, meaning “south.” There are also Gothic and Germanic roots. Before 700 AD Sunday was called "sunny day". Translation also played a role. The original Greek heméra helíou became the Latin dies solis.

Characteristics of the Sun

The Sun is a G-type main sequence star with an absolute magnitude of 4.83, which is brighter than about 85% of the other stars in the galaxy, many of which are red dwarfs. With a diameter of 696,342 km and a mass of 1.988 x 10 30 kg, the Sun is 109 times larger than the Earth and 333,000 times more massive.

It's a star, so the density varies depending on the layer. The average reaches 1.408 g/cm3. But closer to the core it increases to 162.2 g/cm 3, which is 12.4 times higher than on Earth.

It appears yellow in the sky, but the true color is white. Visibility is created by the atmosphere. The temperature increases with proximity to the center. The core is heated to 15.7 million K, the corona - 5 million K, and the visible surface - 5778 K.

Average diameter	1.392 10 9 m
Equatorial	6.9551 10 8 m
Equator circumference	4.370 10 9 m
Polar compression	9 10 −6
Surface area	6.078 10 18 m²
Volume	1.41 10 27 m³
Weight	1.99 10 30 kg
Average density	1409 kg/m³
Acceleration free falls at the equator	274.0 m/s²
Second escape velocity (for surface)	617.7 km/s
Effective temperature surfaces	5778 K
Temperature crowns	~1,500,000 K
Temperature kernels	~13,500,000 K
Luminosity	3.85 10 26 W (~3.75·10 28 Lm)
Brightness	2.01 10 7 W/m²/sr

The sun is made of plasma, therefore it is endowed with high magnetism. There are north and south magnetic poles, and the lines form the activity seen at the surface layer. Dark spots mark cool spots and succumb to cyclicity.

Coronal mass ejections and flares occur when lines magnetic field are being reconfigured. The cycle takes 11 years, during which activity waxes and wanes. Largest quantity sunspots occur at maximum activity.

The apparent magnitude reaches -26.74, which is 13 billion times brighter than Sirius (-1.46). The Earth is 150 million km away from the Sun = 1 AU. It takes 8 minutes and 19 seconds for a light beam to cover this distance.

Composition and structure of the Sun

The star is filled with hydrogen (74.9%) and helium (23.8%). Among the heavier elements are oxygen (1%), carbon (0.3%), neon (0.2%) and iron (0.2%). The inner part is divided into layers: core, radiation and convective zones, photosphere and atmosphere. The core has the highest density (150 g/cm 3) and occupies 20-25% of the total volume.

The star spends a month turning its axis, but this is an approximate estimate, because this is a plasma ball. Analysis shows that the core rotates faster than the outer layers. While the equatorial line spends 25.4 days per revolution, the poles take 36 days.

In the core of a celestial body, solar energy is formed due to nuclear fusion, transforming hydrogen into helium. Almost 99% of thermal energy is created in it.

Between the radiation and convective zones there is a transition layer - tacholine. There is a noticeable sharp change in the uniform rotation of the radiation zone and the differential rotation of the convection zone, which causes a serious shift. The convective zone is located 200,000 km below the surface, where the temperature and density are also lower.

The visible surface is called the photosphere. Above this ball, light can spread freely into space, releasing solar energy. The thickness covers hundreds of kilometers.

The upper part of the photosphere is inferior in heating to the lower part. The temperature rises to 5700 K, and the density is 0.2 g/cm3.

The atmosphere of the Sun is represented by three layers: the chromosphere, the transition part and the corona. The first extends over 2000 km. The transitional layer occupies 200 km and warms up to 20,000-100,000 K. The layer has no clear boundaries, but a halo with constant chaotic movement is noticeable. The corona warms up to 8-20 million K, which is influenced by the solar magnetic field.

The heliosphere is a magnetic sphere extending beyond the heliopause (50 AU from the star). It is also called the solar wind.

Evolution and future of the Sun

Scientists are convinced that the Sun appeared 4.57 billion years ago due to the collapse of part of a molecular cloud represented by hydrogen and helium. At the same time, it started rotation (due to angular momentum) and began to heat up with increasing pressure.

Most of the mass was concentrated in the center, and the rest turned into a disk that would later form the planets we know. Gravity and pressure led to increased heat and nuclear fusion. There was an explosion and the Sun appeared. In the figure you can trace the stages of evolution of stars.

The star is currently in the main sequence phase. Inside the core, more than 4 million tons of matter are transformed into energy. The temperature is constantly rising. Analysis shows that over the past 4.5 billion years, the Sun has become brighter by 30%, with an increase of 1% for every 100 million years.

It is believed that it will eventually begin to expand and become a red giant. Due to the increase in size, Mercury, Venus and possibly the Earth will die. It will remain in the giant phase for approximately 120 million years.

Then the process of decreasing size and temperature will begin. It will continue to burn the remaining helium in the core until the supply runs out. In 20 million years it will lose stability. The earth will be destroyed or heat up. After 500,000 years, only half the solar mass will remain, and the outer shell will create a nebula. As a result, we will get a white dwarf that will live for trillions of years and only then turn black.

Location of the Sun in the galaxy

The Sun is closer to the inner edge of the Orion Arm of the Milky Way. The distance from the galactic center is 7.5-8.5 thousand parsecs. Located inside a local bubble - a cavity in the interstellar medium with hot gas.

We are completely dependent on our star - the Sun. The earth rotates around its axis, the Sun slowly rises above the horizon and illuminates and warms the surface of the earth and everything on it all day long. Without the Sun, there would be no life.

What happened before the Sun? How was it formed?

Just five billion years ago, neither the Sun nor the nine planets surrounding it existed.

The atoms that make up our bodies flew through interstellar space in clouds of gas and dust. Scientists think that this gas cloud, consisting mainly of hydrogen, rotated on its axis. The more dust and gas the cloud collected, the more it contracted, that is, it decreased.

The force that caused the cloud to contract was the force of gravity. Inside the cloud, particles were attracted to particles, joining together. Gradually the cloud began to rotate synchronously with all its parts at the same time.

Example of the formation of the Sun

To clearly show how this happened, astronomer William Hartmann proposed a simple experiment. You need to shake your cup of coffee. The liquid in the cup moves randomly. If you drop a little milk into a cup, the coffee particles will begin to rotate in one direction. Something similar. This also happened in the cloud, in which little by little the random movement of particles was replaced by their ordered synchronous rotation, that is, the cloud began to rotate entirely in one direction.

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Scientists have added a dramatic twist to this story. They believe that when the cloud formed, a star exploded nearby. At the same time, powerful flows of matter scattered in different directions. Some of this material was mixed with the material of the gas and dust cloud of our Solar System. This caused the cloud to shrink even faster.

The more the cloud compressed, the faster it rotated, like a figure skater who, while spinning, presses her arms to her body (and also begins to spin faster). The faster the cloud rotated, the more its shape changed. In the center, the cloud became more convex as more matter accumulated there. The peripheral part of the cloud remained flat. Soon the cloud's shape resembled that of a pizza with a ball in the middle. This ball, yes, you guessed it right, was our child - the Sun. The accumulation of gas in the middle of the “pizza” was larger than the modern size of the entire solar system. Scientists call the newborn Sun a protostar.

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Rotation and pulsation of the Sun

How did the Sun turn from a gas ball into a star?

This happened very, very slowly, over thousands and thousands of years, while the protostar and the surrounding cloud continued to shrink under the influence of gravity. The atoms that made up the cloud collided, releasing heat. The temperature of the cloud increased, especially in the denser center, where the frequency of atomic collisions was higher. The gas in the protostar began to glow. In the depths of the forming Sun, the temperature gradually increased to millions of degrees.

At such unimaginably high temperatures and equally high blood pressure something new began to happen with the atoms squeezed and pressed against each other. Hydrogen atoms began to combine with each other, forming helium atoms. Each time hydrogen was converted into helium, a small amount of energy was released - heat and light. Since this process occurred throughout the core of the Sun, this energy flooded the entire Solar System with light. The sun turned on like an electric lamp gigantic size. From that moment on, the Sun became a living star, the same as we see in the night sky.

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Solar Nuclear Fusion

The sun produces energy through a process called nuclear fusion. Nuclear fusion is a controlled explosion at the center of the Sun, where temperatures range from 15 million to 22 million degrees Celsius. Every second in the depths of the Sun, 4 million tons of hydrogen are converted into helium. The power of the light flux that is emitted is equal to the power of 4 trillion light bulbs.

Interesting fact: When the Sun was young, it was 20 times larger and 100 times brighter than it is now.

What will happen to the Sun next?

It is worth recalling that the reserves of hydrogen on the Sun are limited. Over time, the composition of our star changes. If at the beginning of its history the Sun consisted of 75 percent hydrogen and 25 percent helium, now the hydrogen content has dropped to 35 percent. As you guessed, there comes a moment when hydrogen in the bowels of a star disappears. Like all fuels, hydrogen eventually runs out. The Sun has nowhere to get new hydrogen. The star's core now consists of helium. The core is surrounded by a thin hydrogen shell. The shell's hydrogen continues to transform into helium, but the star has already entered the order of decline.

Our Sun is truly a unique star, if only because its glow made it possible to create conditions suitable for life on our planet Earth, which, either by an amazing coincidence or by God’s ingenious plan, is at an ideal distance from the Sun. Since ancient times, the Sun has been under the close attention of man, and if in ancient times priests, shamans, and druids revered our luminary as a deity (all pagan cults had solar gods), now the Sun is actively studied by scientists: astronomers, physicists, astrophysicists. What is the structure of the Sun, what are its characteristics, its age and location in our galaxy, read on about all this.

Location of the Sun in the galaxy

Despite its enormous size relative to our planet (and other planets), on a galactic scale, the Sun is far from the largest star, but very small, there are stars much larger than the Sun. Therefore, astronomers classify our star as a yellow dwarf.

As for the location of the Sun in the galaxy (as well as our entire solar system), it is located in the Milky Way galaxy, closer to the edge of the Orion Arm. The distance from the center of the galaxy is 7.5-8.5 thousand parsecs. Speaking in simple language, it’s not that we are on the outskirts of the galaxy, but we are also relatively far from the center - a kind of “sleeping galactic area”, not on the outskirts, but not in the center either.

This is what the location of the Sun looks like on a galactic map.

Characteristics of the Sun

According to the astronomical classification of celestial objects, the Sun is a G-class star, brighter than 85% of other stars in the galaxy, many of which are red dwarfs. The diameter of the Sun is 696342 km, mass - 1.988 x 1030 kg. If we compare the Sun with the Earth, it is 109 times larger than our planet and 333,000 times more massive.

Comparative sizes of the Sun and planets.

Although the Sun appears yellow to us, its real color is white. Visibility yellow color created by the atmosphere of the star.

The temperature of the Sun is 5778 degrees Kelvin in the upper layers, but as it approaches the core it increases even more and the core of the Sun is incredibly hot - 15.7 million degrees Kelvin

The Sun also has strong magnetism; on its surface there are north and south magnetic poles, and magnetic lines that are reconfigured every 11 years. At the time of such restructuring, intense solar emissions occur. Also, the magnetic field of the Sun affects the magnetic field of the Earth.

Structure and composition of the Sun

Our Sun is mainly composed of two elements: (74.9%) and helium (23.8%). In addition to them, there are present in small quantities: (1%), carbon (0.3%), neon (0.2%) and iron (0.2%). Inside, the Sun is divided into layers:

• core,
• radiation and convection zones,
• photosphere,
• atmosphere.

The Sun's core has the highest density and occupies approximately 25% of the total solar volume.

The structure of the Sun is schematic.

It is in the solar core through nuclear fusion that transforms hydrogen into helium that thermal energy. In fact, the core is a kind of solar motor, thanks to it, our luminary releases heat and warms us all.

Why does the sun shine

It is precisely the glow of the Sun that occurs due to the tireless work of the solar core, or more precisely, the thermonuclear reaction that constantly occurs in it. The burning of the Sun occurs due to the conversion of hydrogen into helium; this is the eternal thermonuclear reaction that constantly feeds our luminary.

Sunspots

Yes, there are spots on the Sun too. Sunspots are darker areas on the solar surface, and they are darker because their temperature is lower than the temperature of the surrounding photosphere of the Sun. Sunspots themselves are formed under the influence of magnetic lines and their reconfiguration.

sunny wind

The solar wind is a continuous stream of plasma coming from the solar atmosphere and filling the entire solar system. The solar wind is formed because, due to the high temperature in the solar corona, the pressure of the overlying layers cannot balance with the pressure in the corona itself. Therefore, there is a periodic release of solar plasma into the surrounding space. There is a whole separate article about the phenomenon on our website.

A solar eclipse is a rare astronomical phenomenon in which the Moon is the Sun, in whole or in part.

Schematically, a solar eclipse looks like this.

Evolution of the Sun and its future

Scientists believe that our star is 4.57 billion years old. At that distant time, it was formed from part of a molecular cloud represented by helium and hydrogen.

How was the Sun born? According to one hypothesis, the helium-hydrogen molecular cloud began to rotate due to angular momentum and at the same time began to heat up intensely as the internal pressure increased. At the same time, most of the mass concentrated in the center and turned into the Sun itself. Strong pressure led to an increase in heat and nuclear fusion, thanks to which both the Sun and other stars work.

This is what the evolution of a star, including the Sun, looks like. According to this scheme in this moment Our Sun is in a small star phase, and the current solar age is in the middle of this phase. In about 4 billion years, the Sun will turn into a red giant, expand even more and destroy Venus, and possibly our Earth. If the Earth as a planet does survive, then life on it by that time will no longer be possible. Since in 2 billion years the glow of the Sun will increase so much that all the earth’s oceans will simply boil away, the Earth will be incinerated and turn into a complete desert, the temperature on the earth’s surface will be 70 C and if life is possible, it will only be deep underground. Therefore, we still have about a billion or so years to find a new refuge for humanity in the very distant future.

But let's return to the Sun, having turned into a red giant, it will remain in this state for about 120 million years, then the process of decreasing its size and temperature will begin. And when the remaining helium in its core is burned in a constant furnace of thermonuclear reactions, the Sun will lose its stability and explode, turning into a planetary nebula. The Earth at this stage, as well as the neighboring one, will most likely be destroyed by a solar explosion.

In another 500 million years, a white dwarf will form from the solar nebula, which will exist for trillions more years.

• You could fit a million Earths or planets the size of ours inside the Sun.
• The shape of the Sun forms an almost perfect sphere.
• 8 minutes and 20 seconds - this is the time it takes for a sunbeam to reach us from its source, despite the fact that the Earth is 150 million km away from the Sun.
• The word "Sun" itself comes from the Old English word for "south" - "South".
• And we have bad news for you, in the future the Sun will incinerate the Earth, and then completely destroy it. This will happen, however, no earlier than in 2 billion years.

Sun, video

And finally, an interesting scientific documentary from the Discovery Channel - “What the Sun Hides.”

P.S. The sun can also affect human health. To protect yourself from the possible negative effects of sunlight, it is important to use high-quality sun cream, which can be purchased in the online store http://dska.com.ua/

People understood long ago that without the Sun life on Earth would not exist, because he was exalted, he was worshiped, and when celebrating the day of the Sun, they often made human sacrifices. They watched it and, creating observatories, solved such simple at first glance questions about why the Sun shines during the day, what is the inherent nature of the luminary, when the Sun sets, where it rises, what objects are around the Sun, and planned their activities on based on the data obtained.

Scientists had no idea that on the only star in the solar system there are seasons very similar to the “rainy season” and the “dry season.” The activity of the Sun alternately increases in the northern and southern hemispheres, lasts eleven months, and decreases for the same amount of time. Along with the eleven-year cycle of its activity, the life of earthlings directly depends, since at this time powerful magnetic fields are emitted from the bowels of the star, causing solar disturbances that are dangerous for the planet.

Some may be surprised to learn that the Sun is not a planet. The sun is a huge, luminous ball of gases, inside of which thermonuclear reactions constantly occur, releasing energy that gives light and heat. It is interesting that such a star does not exist in the solar system, and therefore it attracts all objects more small sizes, caught in the zone of its gravity, as a result of which they begin to rotate around the Sun along a trajectory.

Naturally, in space the Solar System is not located on its own, but is part of the Milky Way, a galaxy that is a huge star system. The Sun is separated from the center of the Milky Way by 26 thousand light years, so the movement of the Sun around it is one revolution every 200 million years. But the star rotates around its axis in a month - and even then, these data are approximate: it is a plasma ball, the components of which rotate at different speeds, and therefore it is difficult to say exactly how much time it takes for a full rotation. So, for example, in the equator region this happens in 25 days, at the poles - 11 days more.

Of all the stars known today, our Sun is in fourth place in terms of brightness (when a star exhibits solar activity, it shines brighter than when it subsides). By itself, this huge gaseous ball is white, but due to the fact that our atmosphere absorbs short-spectrum waves and the Sun’s ray at the Earth’s surface is scattered, the light of the Sun becomes yellowish, and White color can only be seen on a clear, sunny day against a blue sky.

Being the only star in the Solar System, the Sun is also the only source of its light (not counting very distant stars). Despite the fact that the Sun and Moon are the largest and brightest objects in the sky of our planet, the difference between them is huge. While the Sun itself emits light, the Earth's satellite, being a completely dark object, simply reflects it (we can say that we also see the Sun at night when the Moon illuminated by it is in the sky).

The Sun was shining - a young star, its age, according to scientists, is more than four and a half billion years. Therefore, it refers to a third generation star, which was formed from the remains of previously existing stars. It is rightfully considered the largest object in the solar system, since its weight is 743 times greater than the mass of all the planets revolving around the Sun (our planet is 333 thousand times lighter than the Sun and 109 times smaller than it).

Atmosphere of the Sun

Since the temperature indicators of the upper layers of the Sun exceed 6 thousand degrees Celsius, it is not a solid body: with such high temperature any stone or metal is transformed into gas. Scientists came to such conclusions recently, since previously astronomers had suggested that the light and heat emitted by a star are the result of combustion.

The more astronomers observed the Sun, the clearer it became: its surface has been heated to the limit for several billion years, and nothing can burn for that long. According to one of the modern hypotheses, the same processes occur inside the Sun as in an atomic bomb - matter is converted into energy, and as a result of thermonuclear reactions, hydrogen (its share in the composition of the star is about 73.5%) is transformed into helium (almost 25%) .

Rumors that the Sun on Earth will sooner or later go out are not without foundation: the amount of hydrogen in the core is not unlimited. As it burns, the outer layer of the star will expand, while the core, on the contrary, will shrink, as a result of which the life of the Sun will end and it will transform into a nebula. This process will not begin soon. According to scientists, this will happen no earlier than in five to six billion years.

As for the internal structure, since a star is a gaseous ball, the only thing it has in common with a planet is the presence of a core.

Core

It is here that all thermonuclear reactions occur, generating heat and energy, which, bypassing all subsequent layers of the Sun, leave it in the form of sunlight and kinetic energy. The solar core extends from the center of the Sun to a distance of 173,000 km (approximately 0.2 solar radii). Interestingly, in the core the star rotates around its axis much faster than in the upper layers.

Radiative transfer zone

Photons leaving the nucleus in the radiative transfer zone collide with plasma particles (ionized gas formed from neutral atoms and charged particles, ions and electrons) and exchange energy with them. There are so many collisions that it sometimes takes about a million years for a photon to pass through this layer, and this despite the fact that the plasma density and its temperature at the outer boundary decrease.

Tachocline

Between the radiative transfer zone and the convective zone there is a very thin layer where the formation of a magnetic field occurs - the electromagnetic field lines are stretched by plasma flows, increasing its intensity. There is every reason to believe that here the plasma significantly changes its structure.

Convective zone

Near the solar surface, the temperature and density of matter becomes insufficient for the solar energy to be transferred only through re-radiation. Therefore, here the plasma begins to rotate, forming vortices, transferring energy to the surface, while the closer to the outer edge of the zone, the more it cools, and the gas density decreases. At the same time, the particles of the photosphere located above it, cooled on the surface, go into the convective zone.

Photosphere

The photosphere is the brightest part of the Sun that can be seen from Earth in the form of the solar surface (it is called so conventionally, since a body consisting of gas does not have a surface, so it is classified as part of the atmosphere).

Compared to the radius of the star (700 thousand km), the photosphere is a very thin layer with a thickness of 100 to 400 km.

It is here during manifestation solar activity light, kinetic and thermal energy is released. Since the temperature of the plasma in the photosphere is lower than in other places, and there is strong magnetic radiation, sunspots form in it, giving rise to the well-known phenomenon of solar flares.

Although solar flares do not last long, an extremely large amount of energy is released during this period. And it manifests itself in the form of charged particles, ultraviolet, optical, x-ray or gamma radiation, as well as plasma flows (on our planet they cause magnetic storms negatively affecting people's health).

The gas in this part of the star is relatively thin and rotates very unevenly: its rotation in the equator region is 24 days, at the poles - thirty. In the upper layers of the photosphere, minimum temperatures are recorded, due to which out of 10 thousand hydrogen atoms only one has a charged ion (despite this, even in this region the plasma is quite ionized).

Chromosphere

The chromosphere is the upper shell of the Sun, 2 thousand km thick. In this layer, the temperature rises sharply, and hydrogen and other substances begin to actively ionize. The density of this part of the Sun is usually low, and therefore is difficult to distinguish from the Earth, and it can only be seen in the event of a solar eclipse, when the Moon covers the brighter layer of the photosphere (the chromosphere glows red at this time).

Crown

The corona is the last outer, very hot shell of the Sun, which is visible from our planet during a total solar eclipse: it resembles a radiant halo. At other times it is impossible to see it due to its very low density and brightness.

It consists of prominences, fountains of hot gas up to 40 thousand km high, and energetic eruptions that go into space at great speed, forming the solar wind, consisting of a stream of charged particles. Interestingly, it is the solar wind that is associated with many natural phenomena of our planet, for example, the northern lights. It should be noted that the solar wind itself is extremely dangerous, and if our planet was not protected by the atmosphere, it would destroy all living things.

Earth year

Our planet moves around the Sun at a speed of about 30 km/s and the period of its complete revolution is equal to one year (the length of the orbit is more than 930 million km). At the point where the solar disk is closest to the Earth, our planet is separated from the star by 147 million km, and at the most distant point - 152 million km.

The “movement of the Sun” visible from the Earth changes throughout the whole year, and its trajectory resembles a figure eight, stretched along the Earth’s axis from north to south with a slope of forty-seven degrees.

This happens due to the fact that the angle of deviation of the Earth’s axis from the perpendicular to the orbital plane is about 23.5 degrees, and since our planet revolves around the Sun, the Sun’s rays change their angle every day and hourly (not counting the equator, where day is equal to night). falls at the same point.

In the summer in the northern hemisphere, our planet is tilted towards the Sun, and therefore the rays of the Sun illuminate earth's surface as intensely as possible. But in winter, since the path of the solar disk across the sky is very low, the sun's ray falls on our planet at a steeper angle, and therefore the earth warms up weakly.

The average temperature is established when autumn or spring arrives and the Sun is located at the same distance in relation to the poles. At this time, nights and days are approximately the same length - and on Earth climatic conditions, representing a transitional stage between winter and summer.

Such changes begin to take place in winter, after the winter solstice, when the trajectory of the Sun across the sky changes and it begins to rise.

Therefore, when spring comes, the Sun approaches the vernal equinox, the length of day and night becomes the same. In the summer, June 21, the day of the summer solstice, the solar disk reaches its highest point above the horizon.

Earth day

If you look at the sky from the point of view of an earthling in search of an answer to the question of why the Sun shines during the day and where it rises, then you can soon be convinced that the Sun rises in the east, and its setting can be seen in the west.

This happens due to the fact that our planet not only moves around the Sun, but also rotates around its axis, making a full revolution in 24 hours. If you look at the Earth from space, you can see that it, like most of the planets of the Sun, turns counterclockwise, from west to east. Standing on Earth and observing where the Sun appears in the morning, everything is seen in a mirror image, and therefore the Sun rises in the east.

At the same time, an interesting picture is observed: a person, observing where the Sun is, standing on one point, moves together with the Earth in an easterly direction. At the same time, parts of the planet that are located on the western side, one after another, gradually begin to be illuminated by the light of the Sun. So. for example, the sunrise on the east coast of the United States can be seen three hours earlier before the sun rises on the west coast.

The Sun in the Life of the Earth

The Sun and Earth are so connected with each other that the role of the largest star in the sky can hardly be overestimated. First of all, our planet formed around the Sun and life appeared. Also, the energy of the Sun warms the Earth, the Sun's ray illuminates it, forming a climate, cooling it at night, and after the Sun rises, warms it again. What can I say, even the air with its help acquired the properties necessary for life (if not a ray of the Sun, it would have been a liquid ocean of nitrogen surrounding blocks of ice and frozen land).

The Sun and Moon, being the largest objects in the sky, actively interacting with each other, not only illuminate the Earth, but also directly influence the movement of our planet - a striking example of this action is the ebb and flow of the tides. They are influenced by the Moon, the Sun plays a secondary role in this process, but they cannot do without its influence either.

Sun and Moon, Earth and Sun, air and water flows, the biomass that surrounds us, are accessible, constantly renewable energy raw materials that can be easily used (it lies on the surface, it does not need to be extracted from the bowels of the planet, it does not generate radioactive and toxic waste).

To draw public attention to the possibility of using renewable energy sources, since the mid-90s. last century, it was decided to celebrate International Sun Day. Thus, every year, on May 3, on the day of the Sun, seminars, exhibitions, and conferences are held throughout Europe aimed at showing people how to use the ray of the luminary for good, how to determine the time when sunset or dawn of the Sun occurs.

For example, on the day of the Sun you can attend special multimedia programs, see huge areas of magnetic disturbances and various manifestations of solar activity through a telescope. On the day of the Sun, you can look at various physical experiments and demonstrations that clearly demonstrate how powerful a source of energy our Sun is. Often on the Day of the Sun, visitors have the opportunity to create a sundial and test it in action.