There are many small and large stars in outer space. And if we talk about the inhabitants of the Earth, then the most important star for them is the Sun. It consists of 70% hydrogen and 28% helium, less than 2% of metals.
If not for the Sun, perhaps there would be no life on Earth. Our ancestors knew how much their way of life and life depended on the heavenly luminary, worshiped and deified it. The Greeks called the sun Helios, and the Romans called it Salt.
The sun has a huge impact on our lives. This is a huge incentive to study how changes occur inside this "fireball" and how these changes can affect us now and in the future. Numerous scientific studies give us the opportunity to look into the distant past of the planet. The sun is about 5 billion years old. After 4 billion years, it will shine much brighter than now. In addition to increasing luminosity and size over many billions of years, the sun is changing for shorter periods of time.
Such a period of change is known as the solar cycle, at the moments of which the minima and maxima of solar activity are observed . Thanks to observations over several decades, it was found that the increase in light activity and the size of the Sun, which began in the distant past, exists now. Over the past few cycles, light activity has increased by about 0.1%. These changes, whether they are quick or gradual, definitely have a huge impact on earthlings. However, the mechanisms of this influence have not yet been fully studied.
The temperature of the Sun in the center of the star is very high, about 14 billion degrees. In the core of the planet thermonuclear reactions occur, i.e. fission reactions of hydrogen nuclei under pressure, as a result of which one helium core and a huge amount of energy are released. With a deepening inward, the temperature of the Sun should increase rapidly. It can only be determined theoretically.
The temperature of the Sun in degrees is:
- crown temperature - 1500000 degrees;
- core temperature - 13500000 degrees;
- the temperature of the Sun in Celsius on the surface is 5726 degrees.
A huge number of scientists from different countries are conducting research on the structure of the Sun, trying to recreate the process of thermonuclear fusion in terrestrial laboratories. This is done in order to find out how plasma behaves in real conditions, in order to repeat these conditions on Earth. The sun, in fact, is a huge natural laboratory.
The atmosphere of the Sun about 500 km thick is called the photosphere. Thanks to convection processes in the planet’s atmosphere, heat fluxes from the lower layers move to the photosphere. The sun rotates, but not like the Earth, Mars ... The sun is basically an unstable body.
Similar effects of the Sun's rotation are observed in gas planets. Unlike the Earth, layers on the Sun have different rotation speeds. The equator rotates the fastest; one revolution is completed in about 25 days. When moving away from the equator, the rotation speed decreases, and somewhere at the poles of the sun the rotation takes about 36 days. The power of the Sun is about 386 billion megawatts. Every fraction of a second, about 700 million tons of hydrogen become 695 million tons of helium and 5 million tons of energy in the form of gamma rays. Due to the fact that the temperature of the Sun is so high, the transition of hydrogen to helium is successfully underway.
The sun also emits a stream of low density charged particles (mainly protons and electrons). This stream is called the solar wind, which spreads throughout the solar system at a speed of about 450 km / s. Streams continuously flow from the Sun into space, respectively, and towards the Earth. The solar wind carries a mortal threat to all life on our planet. It can have dramatic consequences for the Earth: from power line surges, radio interference to beautiful auroras. If there was no magnetic field on our planet, then life would cease in a matter of seconds. The magnetic field creates an impenetrable barrier to the fast charged particles of the solar wind. In the areas of the North Pole, the magnetic field is directed inside the Earth, due to which the accelerated particles of the solar wind penetrate much closer to the surface of our planet. Therefore, at the north pole we observe the polar aurora borealis. The solar wind can also cause danger when interacting with the Earth’s magnetosphere. This phenomenon is called magnetic storms. Magnetic storms have a strong effect on people's health. Especially these reactions are noticeable in the elderly.
The solar wind is not everything that the Sun can harm us. A great danger is solar flares, often occurring on the surface of the body. Flashes emit a huge amount of ultraviolet and x-ray radiation, which is directed towards the Earth. These emissions are completely capable of absorbing the earth's atmosphere, but they carry a great danger to all objects in space. Radiation can be harmful to artificial satellites, stations and other space technology. Also, radiation adversely affects the health of astronauts working in outer space.
Since its inception, the Sun has already used about half of the hydrogen in the core, and will continue to radiate for another 5 billion years, gradually increasing in size. After this period of time, the remaining hydrogen in the core of the star will be completely exhausted. By this time, the Sun will reach its maximum size and increase in diameter by about 3 times (compared with the current value). It will resemble a red giant luminous ball. Part of the planets close to the Sun will burn out in its atmosphere. These will include the Earth. By that time, humanity will have to find a new planet for living. After which the temperature of the Sun will begin to fall and, cooling, it will turn over time into a "white dwarf". However, this is all a matter of a very distant future ...