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The sun is an ordinary star, its age is about 5 billion years. In the center of the sun, the temperature reaches 14 billion degrees. In the solar core, hydrogen is converted into helium, with a huge amount of energy released. On the surface, the sun has spots, bright flashes occur and explosions of colossal force can be seen.

The solar atmosphere has a thickness of 500 km. and is called a photosphere. The surface of the Sun is bubble. These bubbles are called Solar granularity, and you can see it only through a special solar telescope.
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Due to convection in the solar atmosphere, the thermal energy from the lower layers is transferred to the photosphere, giving it a foamy structure. The sun does not rotate like a solid heavenly body like the Earth. Unlike the Earth, different parts of the Sun rotate at different speeds. The equator is the fastest turning, making one turn in 25 days.

At a distance from the equator, the rotation speed decreases, and in the polar regions the turn takes 35 days. The sun will still exist for 5 billion years, gradually warming up and increasing in size. When all the hydrogen in the central core is consumed, the Sun will be 3 times more than now.

eventually the sun will cool down, turning into a white dwarf. At the poles of the Sun, the acceleration of gravity is 274 m / s2. Chemical composition: hydrogen (90%), helium (10%), other elements less than 0.1%. The sun is removed from the center of our galaxy by 33,000 light years. It moves around the center of the galaxy at a speed of 250km / s, making a full defense for 200000000 years.

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The sun is a spherically symmetric body, which is in equilibrium. Everywhere at the same distances from the center of this sphere the physical conditions are the same, but they change noticeably as we approach the center. Density and pressure rapidly increase in depth, where the gas is more compressed by the pressure of the overlying layers. Consequently, the temperature also increases as we approach the center. Depending on the change in physical conditions, the sun can be divided into several concentric layers, gradually changing into each other.

In the center of the sun, the temperature is 15 million degrees, and the pressure exceeds hundreds of billions of atmospheres. The gas is compressed here to a density of about 1.5 × 105 kg / m3. Almost all of the energy of the Sun is generated in the core - the central region with a radius of about 1/3 of the sun.

Through the layers surrounding the central part, this energy is transferred to the outside. First, energy is transferred by radiation. However, each photon spends millions of years in order to pass through the radiation zone: light is repeatedly absorbed by the substance and is emitted again. It is believed that the radiation zone extends about 1/3 of the radius of the Sun.

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Over the last third of the radius, there is a convection zone. The cause of mixing (convection) in the outer layers of the Sun is the same as in a boiling kettle: the amount of energy coming from the heater is much greater than that given by the thermal conductivity. Therefore, the substance is forced to come into motion and begins to transfer heat itself.

All the layers of the sun considered above are virtually unobservable. Their existence is known either from theoretical calculations or from indirect data.

Over the convective zone are directly observed layers of the Sun, called its atmosphere. They are better studied, because their properties can be judged from observations.

The solar atmosphere also consists of several different layers. The deepest and thinnest of them is the photosphere, directly observed in the visible continuous spectrum. The thickness of the photosphere is only about 300 km. The deeper the layers of the photosphere, the hotter they are. In the outer cooler layers of the photosphere, against the background of the continuous spectrum, Fraunhofer absorption lines are formed.

During the greatest tranquility of the terrestrial atmosphere, a characteristic granular structure of the photosphere can be observed in the telescope. The alternation of small bright spots - granules - about 1000 km in size, surrounded by dark spaces, creates the impression of a honeycomb structure - granulation. The occurrence of granulation is associated with the convection occurring under the photosphere. The individual granules are several hundred degrees hotter than the surrounding gas, and within a few minutes their distribution over the disk of the Sun changes. Spectral measurements indicate the movement of gas in granules similar to convective: in the granules, the gas rises, and between them it drops.

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Expanding into the upper layers of the solar atmosphere, the waves that arise in the convective zone and in the photosphere transmit to them a part of the mechanical energy of the convective motions and produce the heating of gases of the subsequent layers of the atmosphere, the chromosphere and the corona. As a result, the upper layers of the photosphere with a temperature of about 4500K turn out to be the "coldest" ones on the Sun. Both deep down and upward from them, the temperature of the gases rapidly increases.

Located above the photosphere, a layer called the chromosphere, during total solar eclipses in those minutes when the Moon completely covers the photosphere, is visible as a pink ring surrounding the dark disk. At the edge of the chromosphere, there are protruding flames of flame, chromospheric spicules, which are elongated columns of compacted gas. At the same time, one can observe the spectrum of the chromosphere, the so-called flash spectrum. It consists of bright emission lines of hydrogen, helium, ionized calcium and other elements that suddenly flash during the full phase of the eclipse.Selecting the radiation of the Sun in these lines, you can get their image in them. The chromosphere differs from the photosphere by a much more irregular and heterogeneous structure. Noticeably two types of heterogeneity - bright and dark. In size, they exceed the photospheric granules. On the whole, the distribution of inhomogeneities forms the so-called chromospheric mesh, which is especially noticeable in the ionized calcium line. Like granulation, it is a consequence of the movements of gases in the subphotospheric convective zone, only occurring on a larger scale. The temperature in the chromosphere grows rapidly, reaching tens of thousands of degrees in its upper layers.