sun in space

SUN – Formation and Structure UPSC

Sun is the center and source of energy of the solar system. It is a medium age star. It is currently in a state of perfect balance. As a result of which life has become possible in its neighborhood. Its diameter is 13.84 lakh km. The temperature of its center is 15 million degree centigrade. 70 percent of its mass is hydrogen, 28% helium and 2% other heavy elements (such as lithium, uranium). As a result of nuclear fusion, it is providing us 40 lakh tonnes of energy per second in the form of insolation. The current age of the Sun is 4.7 billion years, which is about half of its total age (10 billion years). More than 60 elements found on Earth are also found in the solar spectrum.

Internal Structure of the Sun

There are three levels from the center of the Sun to the surface.

  1. Core
  2. Radiative Zone
  3. Convective zone


The diameter of the center of the Sun is 3.48 lakh km. Is . The temperature here is 15 million degree centigrade. At this temperature, the atom splits into electrons and nuclei, due to which plasma is formed. In such a situation, the nuclei of the atoms collide with each other at high speed and react with nuclear fusion. In extremely hot plasma, the nuclei of hydrogen atoms convert hydrogen into helium by interaction. As a result, a large amount of energy is released. It is known that plasma is the fourth state of matter. The other three states are – solid, liquid and gas –

Radiative Zone

The width of this belt is 3.82 lakh km. Which covers the center from all sides. The energy-carrying photons X and gamma rays generated in the center of the Sun pass through its dense gaseous belt.

Convective Zone

1.39 lakh km surrounding the radiation belt. The convective belt of thickness forms the third layer. This layer is made up of cells. Large cells are found below and small cells are found above. Solar energy comes out through these cells.

The circle above the surface of the Sun is also divided into 3 parts:

1.Photo sphere

The surface of the convective belt i.e. the surface of the Sun is called the photosphere. Its temperature is 6000°c. * Light is made up of many colors, some of which are absorbed by the photosphere itself. Wherever there is absorption of colors by the photosphere, black lines start appearing there. These lines are called Fraunhofer lines. * Sunspots are found only on this circle. * It is known that the photosphere is kept in both the surface and the near (a few hundred km) atmosphere of the Sun.


The chromosphere is the atmosphere of the Sun. It is 2000-3000 km as a cover above the light board. spread in thickness. It is made of hot gases, but the density of the gases decreases on going out of the photosphere and the temperature increases. That is, the density of gases in the chromosphere is less and the temperature is more than in the photosphere.
The rising flow of gases in the chromosphere is called the spicule, which reaches the corona. Sometimes light of intense intensity is generated in this circle, which is given the likeness of a solar flare. * X and gamma rays emerge from this flame and matter is thrown out at an average rate of 800 km/s. It is noteworthy that the color spectrum starts from the upper layer of the photosphere where the negative hydrogens are reduced.


It is the outermost cover of the Sun’s atmosphere, which is found above the chromosphere. Its expansion is several million km. is found till Towards the outside, it gradually weakens and converts into winds of ions and electrons. This wind that flows through the entire solar system is called ‘Solar Wind‘. * Red colored flames rise in this circle which go up to a great height. Sometimes these flames also enter the corona forming an arc. This phenomenon is called prominence. * Radio waves emerge from the corona. There is a hole in this circle above the polar parts of the Sun, which is called the corona hole.

Future of the SUN

Black Dwarf

When the central core of the Sun is completely converted into helium, the production of energy will stop, and the core will shrink. This event will take an additional 5 billion (billion) years to complete. During this time the size of the Sun will become huge and the planets Venus and Mercury will be swallowed by the Sun. The earth will be burnt to ashes. When the core’s fuel is completely exhausted, then the Sun will appear as a giant red body, which will be called a red giant. Protons and electrons will be freed from the gravitational pressure and electron gas will be formed. In this situation, the condition of the star will be called White Dwarf. When the white dwarf gradually cools down, then its own brightness will end, the above condition will be given the analogy of Black Dwarf. In this way the sun will disappear in the form of Black Dwarf.

Cosmic Year

Our Sun is located in the intermediate spinner of our galaxy ‘Mandakini’. Like Earth, it revolves around its Milky Way in 250 million i.e. 250 million years. This period is called the solar year.

Solar Rotation

The Sun rotates on its axis from west to east, which is called solar revolution. * Its orbital period varies with latitude. The equatorial region of the Sun completes one rotation in 24.47 days. * The Sun rotates at the fastest speed at the lower latitudes. * There is a difference in its rotation speed at each latitude. There is also a difference in the rotation speed of the Sun’s photosphere, convection belt and radiation belt. The Sun makes an angle of 7 degrees on its axis.

Sun Spots

Sun Spots are those regions of the photosphere where the temperature is 1500°C lower than that of the circumpolar region. These spots are produced between 5° to 40° north and south latitudes of the Sun. Their inner black part is called Umbra and the relatively less black part located all around is called Penumbra. Generally, they are produced in a community of 2 to 20. But their number can be up to 100 at a time. The lifetime of a sunspot varies from a few hours to a few months. They appear at a time interval of about 11.1 years. * It is also given the noun of solar cycle. The magnetic field at the time of a sunspot is about 100 to 4000 gasses. As soon as it ends, the magnetic field spreads towards the poles. According to the latest researches, the presence of sun-spot affects the climate condition on the earth to a great extent. It affects the North American jet stream air. The process of ‘Alaninos’ along the equator is also related to sunspots. Due to this, many other obstacles arise like upheaval in the earth’s ionosphere, magnetic storms, obstacles in radio communication.

Solar Winds

In addition to electromagnetic short wave radiation, charged particles of protons and electrons are ejected from the Sun; Solar winds flow due to the effect of these ions and electrons, as a result of which the solar corona expands. The speed of the solar wind near the Earth’s orbit is 400 km. per second and their density is generally 2 to 10 ions per cubic cm. it happens. Due to their effect, the ionized gas layer of the Earth’s atmosphere decreases and Aurora appears on the poles.

Loader image

Leave a Reply

Your email address will not be published. Required fields are marked *