The sun has a significant effect on the earth and without it, the formation of life on earth would not be possible. This star influences the weather, ocean currents, seasons, and climate of the earth. It enables the growth of plant life through photosynthesis and is a source of heat for life on Earth.

The Sun is an ordinary star and one of the 100 billion stars in the Milky Way galaxy, which is approximately 25,000 light-years away from the center of the galaxy. The sun is a relatively young star and is part of the generation of stars called population 1, which are mainly composed of elements heavier than helium. The oldest generation of stars is called population 2 and the oldest generation of stars is called population 3. Of course, no stars from the population 3-star generation have been definitively identified yet.

The sun was formed about 4.6 billion years ago. According to many scientists, the sun and other planets of the solar system were formed from a huge and rotating cloud of gas and dust called the solar nebula. As the nebula collapsed under its own gravity, its rotation speed increased and it became a disk. Much of the material of the disk was pulled towards the center and formed the Sun. The remnants of the nebula led to the formation of planets, asteroids, comets, and other objects in the solar system.

The Sun is in a period of its stellar life when it produces helium by burning hydrogen. The mass difference between hydrogen atoms and its child helium atom is released in the form of energy. This energy is the heat and light that sustains our planet. This stage of Khushid’s life is called the main field.

At first, main sequence stars such as the sun form a mass known as a protostar. Then they gradually collect mass from their surroundings and reach the mass required to start nuclear fusion; Like all main sequence stars, most of the Sun’s mass is hydrogen, with some helium and traces of heavier elements. The amount of heavier elements is called the metallicity of the star (according to the astronomical definition, metal is any element heavier than helium).

73% of the sun’s mass is hydrogen, 25% is helium, and the remaining 2% is made up of other metals. The progenitors of stars before the Sun probably had lower metallicity ratios and filled the galaxies with large amounts of metal after their deaths.

The more massive a star is, the faster it burns its hydrogen content. Some of the largest stars, such as those with 40 times the mass of the Sun, have lifetimes as short as a million years. While the lifespan of main sequence stars like the sun can reach 10 billion years.

The sun and its atmosphere are divided into several regions and multiple layers. The interior of the sun consists of the core, the radiative region, and the convective region. The sun’s atmosphere includes parts of the photosphere, chromosphere, transition zone, and solar corona. Beyond this region is the solar wind, or outflow of gas from the solar corona.

The core of the sun occupies only 2% of its volume; However, its density is 15 times that of lead and it has almost half the mass of the sun. Then we reach the radiative zone, which constitutes 32% of the Sun’s volume and 48% of its mass. The light of the nucleus is scattered in this region so that a photon needs about a million years to pass through it.

The photosphere is the lowest layer of the Sun’s atmosphere and emits the light we see. The photosphere is approximately 500 km thick, although most of its light comes from the lower third. The temperature of the photosphere varies between 6125 degrees Celsius in the lower part and 4125 degrees Celsius in the upper part.

Then we reach the transition zone, whose thickness is between several hundred and several thousand kilometers. This region is also heated by the solar corona above it and emits a large part of the light in the form of ultraviolet rays.

Finally, we reach the super-hot solar corona, which has structures such as rings and streams of ionized gas. The temperature of the solar corona varies between 500,000 and 6 million degrees Celsius, and even in the event of a solar flare, this temperature can reach tens of millions of degrees Celsius. Materials from the solar corona are released in the form of the solar wind.

The Sun’s magnetic field is defined by a combination of three complex mechanisms: a central electric current that runs through the Sun, layers of the Sun that rotate at different speeds, and the Sun’s ability to conduct electric current. Near the Sun’s equator, the magnetic field lines form small rings near the surface. The magnetic field lines that flow through the poles travel thousands of kilometers to reach the opposite pole.

The Sun’s magnetic field is almost twice as strong as the Earth’s magnetic field. However, it is highly concentrated in some small areas, so that its strength reaches 3000 times the normal level. These changes lead to the creation of features such as sunspots to spectacular eruptions known as flares and mass ejections from the solar corona.

The sun rotates around its axis just like the earth. This rotation is counterclockwise and it takes between 25 and 53 days to complete one rotation. The Sun also rotates clockwise around the center of the Milky Way. The Sun’s orbit is between 24,000 and 26,000 light years away from the center of the galaxy. It takes 225 million to 250 million years for the Sun to make a complete revolution to the center of the galaxy.

The sun is approximately 150 million kilometers away from the earth. This distance called an astronomical unit (AU), has become the standard scale for measuring the distance between stars and planets. An astronomical unit can be measured based on the speed of light or the time it takes for a photon of light to travel from the Sun to Earth.

It takes approximately eight minutes and nineteen seconds for sunlight to reach the Earth. The radius of the sun or its distance from the center is approximately 700 thousand kilometers. This distance is about 109 times the radius of the Earth. The Sun is not only larger in radius than the Earth, but its mass is 333,000 times that of the Earth. Also, 99.8% of the total mass of the solar system belongs to the sun.

The influence of the sun on the earth is very impressive. The sun is responsible for the formation of life on our planet and without it, we would not exist. Plants and animals depend on the sun to grow. Plants obtain their food through a process called photosynthesis. In addition to water and carbon dioxide, the sun helps plants produce glucose. Glucose is a type of sugar that acts as food for plants.

In addition, another product of photosynthesis is oxygen, which plants release from themselves. On the other hand, we humans need oxygen for our lives. For this reason, plants are often called the lungs of the earth. Plants in the oceans, such as phytoplankton and seaweed, use sunlight for photosynthesis. In this way, the ocean produces half of the oxygen in the world. On the other hand, the oceans absorb a large part of the carbon dioxide on the earth.

The sun is the main driver of the Earth’s climate and ocean currents. The heat of the sun is unevenly distributed on the earth. Areas around the equator receive direct sunlight and are therefore warmer than areas near the poles. The heat from the equator moves towards the poles and creates currents. This movement transports nutrients into the oceans and helps regulate the climate.

On the other hand, for humans, the day and night cycle is the basis for daily activities. Humans are often active during the day. Sunrise signals indicate the beginning of the day and sunset signals rest time.

In addition to setting the body clock, the sun has direct benefits on our overall health. Sunlight is good for bones and helps improve our health. Our body produces vitamin D through exposure to direct sunlight. It also helps to produce serotonin, the feel-good hormone and boosts our sense of energy. However, moderation is important, as too much sun exposure can lead to sunburn.

Sunspots are dark and relatively cold spots on the sun’s surface that often have a circular appearance. These spots appear when dense parts of the Sun’s magnetic field lines make their way from the inner space to the Sun’s surface.

The number of sunspots depends on the solar magnetic activity. The change in the number of spots from a minimum to a maximum of 250 spots and then back to the minimum value is called the solar cycle. This cycle repeats almost every 11 years.

The Sun is almost halfway through its main sequence life and has been burning hydrogen for 4.5 billion years. Our star is in a constant battle because the external radiation pressure from the nuclear fusion process is always in balance with the external gravitational forces. When the sun’s core hydrogen runs out in about 5 billion years, no force will be able to counter the inward force of gravity.

Finally, the center of the sun undergoes gravitational collapse and turns into a compact core. In the next stage, helium fusion occurs and elements such as carbon, nitrogen, and oxygen are produced. In this way, the sun enters the red giant phase and spreads its outer layers into space. During this phase, the Sun will swallow the inner planets of the Solar System, such as Mercury, Venus, and possibly Earth. Finally, after millions of years, with the release of all the outer layers, the core of the Sun remains in the form of a white dwarf. The white dwarf loses its heat over time and theoretically turns into a cold object called a black dwarf.

Ancient cultures often altered natural stone structures or built stone monuments to mark the movements of the sun and moon, thus recognizing the seasons, creating calendars, and tracking the process of solar and lunar eclipses. According to the belief of many ancient people, the sun revolved around the earth, so Ptolemy, the ancient Greek researcher, made the central earth model in 150 BC. In 1543, Nicolaus Copernicus presented the sun-central model of the solar system, and in 1610, the discovery of Jupiter’s moons by Galileo Galilei confirmed the hypothesis that all celestial bodies do not revolve around the Earth.

In 1990, NASA and the European Space Agency launched the Ulysses probe to observe the polar regions of the Sun. In 2004, NASA’s Genesis spacecraft returned samples of the solar wind to Earth for research. In 2007, the STEREO dual probe released the first 3D images of the Sun. NASA lost contact with STEREO-B in 2014. SETERO-A continued to operate.

The Solar and Heliospheric Observatory (SOHO) is one of the most important solar probes designed to study the solar wind and the outer layers and internal structure of the Sun. Among the important achievements of this probe, we can mention the following: photographing the structure of subsurface sunspots, measuring the acceleration of solar winds, discovering corona waves and solar tornadoes, discovering more than 1000 comets, creating a revolution in the human ability to predict space weather.

The Solar Dynamics Observatory (SDO), launched in 2010, has released unprecedented detail of sunspot outflows, as well as close-up images of the Sun’s surface activity and precise measurements of solar flares across a wide range of ultraviolet wavelengths.

The most recent spacecraft added to the Sun Observing fleet are the Parker Solar Probe and the Solar Orbiter spacecraft from NASA and the European Space Agency, which were launched in 2018 and 2020, respectively. Both probes are moving in unprecedentedly close orbits around the Sun, providing complementary measurements of the star’s environment.

On its closest approach to the Sun, the Parker probe entered the Sun’s outer atmosphere, or corona, and withstood its extremely hot temperatures. At its closest, this spacecraft is located at a distance of 6.5 million kilometers from the surface of the sun. The measurements help scientists learn more about the Sun’s energetic currents, the structure of the solar wind, and how energetic particles are accelerated and transported.

Although the Solar Orbiter will not fly as close to the Sun as the Parker Probe, it is equipped with advanced cameras and telescopes that take pictures of the star’s surface as close as possible. It was technically impossible for the Parker probe to carry such a camera to directly photograph the Sun. The Parker probe has also flown through a Coronal Mass Eruption (CME) in its most recent attempt.

Solar Orbiter is closest to the Sun at an altitude of 43 million kilometers from this star, which is 25% closer to the Sun than Mercury. This orbiter has recorded a collection of the closest images to the Sun and unprecedented features such as miniature flares.

Up to this section, we have provided almost all the necessary information about the sun. However, there are some facts about this amazing star that you have rarely heard.

• The sun constitutes 99.86% of the total mass of the solar system. The sun has a mass of 330,000 times the mass of the Earth. Three-quarters of the sun is hydrogen and the rest is helium. Therefore, the sun is the heaviest object in the solar system.
• More than a million Earths fit in the Sun. If you were to fill a hollow sun with spherical Earths, it would fit nearly 960,000 Earths inside. However, if you want to make sure that no space is wasted, 1,300,000 crushed Earths fit inside the Sun. The surface area of ​​the sun is 11,990 times the area of ​​the Earth.
• One day, the sun will destroy life on Earth. The sun will eventually run out of hydrogen fuel after five billion years. Finally, this star expands and enters the red giant phase. As a result, the Sun will swallow the planets Mercury and Venus and possibly the Earth.
• The energy produced by the Sun’s core is called nuclear fusion. Most of the sun’s energy is produced when four hydrogen nuclei combine to form a helium nucleus.
• The sun is almost a perfect sphere. Considering the sheer dimensions of the sun, there is only a ten kilometer difference between its polar and equatorial diameters; And this feature makes the Sun the closest object to a perfect sphere in nature.
• The sun is moving at a speed of 220 km/s. The Sun is between 24,000 and 26,000 light-years away from the center of the galaxy. It takes approximately 225 to 250 million years for the Sun to make a complete orbit around the center of the Milky Way.
• The sun will eventually become the same size as the Earth. When the Sun ends its red giant phase, it undergoes internal collapse. The large mass of the Sun is conserved, yet this large mass is condensed into an Earth-sized volume. When this happens, the Sun enters the white dwarf phase.
• It takes eight minutes for sunlight to reach the earth. The average distance between the sun and the Earth is approximately 150 million kilometers. Light travels at a speed of 300,000 kilometers per second, by dividing these numbers we get 500 seconds or eight minutes and twenty seconds. Energy from the Sun reaches the Earth in just a few minutes, but it takes millions of years to reach the surface of the Sun’s core.
• The sun is in the middle of its life. With a lifetime of 4.5 billion years, the Sun has burned almost half of its hydrogen storage and has enough storage for the next 5 billion years. Currently, the Sun is a yellow dwarf star.
• The distance between the Earth and the Sun changes. The reason for this problem is the movement of the Earth in an elliptical orbit around the sun. For this reason, the distance between the Earth and the Sun varies between 147 and 152 million kilometers.
• The sun revolves around the Earth. If you look at the sun from the north, the sun rotates in a counter-clockwise direction, i.e. from east to west. This process is similar to all the planets of the solar system except for Venus and Uranus.
• The rotation of the sun at the equator is faster than the rotation of its poles. This phenomenon is called differential rotation.
• The sun produces the solar wind. These winds are plasma eruptions or very hot charged particles that originate from a layer of the sun called the solar corona. These particles can move at a speed of 450 km/s in the solar system.
• The sun belongs to the group of yellow dwarf stars. The sun is a type of main sequence star with a surface temperature between 5000 and 5700 degrees Celsius, which is included in the group of yellow dwarf stars.
• The auroras are the result of the collision of the solar wind with the Earth’s atmosphere. When the sun’s charged particles collide with the earth’s atmosphere, beautiful aurora borealis in different colors are created, and as the name aurora borealis suggests, they are mostly seen in the polar regions and near the poles.

The sun is the star responsible for the emergence and continuation of life on Earth, which constitutes nearly 99.8% of the total mass of the solar system. This yellow dwarf star, which is in the main sequence stage of its life, was formed about 4.6 billion years ago from a huge cloud of gas and dust. Gradually, the planets formed around the sun.

The sun has a great influence on the earth’s climate and weather, and since thousands of years ago, humans have used the sun to regulate their daily activities. In about 5 billion years, the life of the Sun will end and by entering the red giant phase, the rocky planets will swallow the inner part of the solar system. So far, researchers have sent many probes to the Sun, which have resulted in amazing data on the structure of the Sun.