The Sun is the center of our solar system. It is radiant and powerful, bringing warmth and life to the Earth. Since ancient times, people have regarded the Sun as a symbol of light and power, and have admired and worshipped it. As a result, there are many myths about the sun, the most famous of which is the story of Hou Yi, the man who shot the sun. Legend has it that in ancient times, there was a huge Fusang tree in a place called Tanggu in the East China Sea, on which there were ten suns, and one of them went out every day to shed warm sunshine on the earth. One day, the ten suns had a whim to come out and play together. The ten suns appeared in the sky at the same time, causing the earth to dry up, the herbs to scorch, and people to find it difficult to live. Emperor Yao ordered Hou Yi, who was good at archery, to shoot down nine of the suns. When the sun fell to the ground, it turned into a crow that was hit by an arrow. Only one sun was left in the sky, and life on earth returned to normal. This beautiful story reflects the close relationship between the sun and human beings.
The real sun could never have been ten, much less shot down with an arrow. The sun is simply too big. Therefore its enormous energy is unimaginable. Such energy only needs 40 seconds to make the ice covering the entire surface of the Earth 100 kilometers thick all melted. Such a large amount of energy billions of years of continuous loss in all directions, the Earth is only 2.2 billionths of one of them. The sun's ability to emit light has not seen any reduction, where does its energy come from? Like other stars, the Sun derives its energy from the thermonuclear reaction in which hydrogen nuclei fuse into helium nuclei. The Sun can be said to be a giant hydrogen bomb that is constantly exploding. The composition of the Sun is then clear: it is mainly composed of hydrogen and helium, of which hydrogen accounts for 78.4% and helium for 19.8%. But through spectral analysis, it was found that the sun has many other elements, such as carbon, nitrogen, oxygen and various metals, which are all found on Earth.
The Sun and the Earth contain about the same elements, but in very different physical states. The temperature of the Sun is very high, about 6,000 degrees Celsius on the surface and up to 15 million degrees Celsius in the interior, which makes it radiate a dazzling light forever. People want to take a closer look at its face ah, but the dazzling light hindered people's observation, until the high degree of scientific and technological development of today, people can basically see the true face of the sun. It turns out that the sun is divided into two parts: the inner core and the atmosphere. Its internal situation we do not quite understand, but already know that the atmosphere is divided into three layers. Usually see a round of red sun is the surface layer of the sun, called photosphere. Beyond the photosphere is a layer of dark red atmosphere called the chromosphere, which erupts in long tongues of fire. The outermost layer is called the corona and is very irregular in shape. The sun's energy comes from the inside and is transferred layer by layer to the surface, where it is emitted into cosmic space in the form of radiation. The huge flames that erupt from the chromosphere are called heliostats. The large corona is 225,000 kilometers high, 19 Earths lined up to be that high. The outermost layer of the corona is the outer atmosphere of the sun, which is usually hard to see, with a brightness equal to that of the moon, but a temperature of 1 to 2 million degrees Celsius. Coronal material all ionized, due to the thin density of the material, rapid movement of charged particles will be part of the sun to break free from the gravitational pull of the sun, like a wildebeest run in all directions, which formed the solar wind.
What is in the solar wind? With artificial satellites to capture the solar wind point of mass, found that its main component is the proton, that is, the hydrogen nucleus, accounting for 91.3%; followed by helium nucleus, accounting for 8.6%; and a small number of other elements of ions and some free electrons. The solar wind runs very fast, and the speed of the solar wind that reaches the Earth is still 450 kilometers per second, 500 times faster than a rifle bullet. Particle movement is intense, the temperature is high, so the temperature of the proton is about 40,000 degrees Celsius, the temperature of the electron is about 100,000 degrees Celsius. Will such a "hot" wind scorch the earth? No, it won't. Because the density of the solar wind is very low, about 8 particles per cubic centimeter, so the overall energy has little effect on the Earth.
The Sun has always been sacred in people's minds. But later, through telescope observation, people found that the sun also has clusters of dark spots, which are sunspots. In ancient times, people also saw sunspots in the dark weather, but could not figure out what they were, so they made up stories based on their imagination, saying that there were three-legged crows on the sun. How ridiculous this imagination seems today, but for a long time people used "golden crow" to call the sun. In the Tang Dynasty, Han Yu, a great writer, described the sun in a poem: "The golden crow first flew to the bottom of the sea, and the blue sky opened up with the radiance of the Zhu Hui." Now people already know "black" is the sun photosphere on the temperature than the surrounding 1,000 ~ 2,000 ℃ lower dark spot, has a strong magnetic, magnetic field strength can reach 3,000 ~ 4,000 gauss, while the earth's magnetic field strength is less than 1 gauss. Dark spots often appear in pairs, one at the magnetic north pole and the other at the magnetic south pole. Sometimes there are many small sunspots around the large one. Sunspots sometimes more, sometimes less, from more to less have a certain periodicity, the average cycle is 11 years. Although people no longer feel strange about the sun on the black, but the cause of the black, activity cycle and other issues still lack of essential knowledge.
In addition to the black, the sun has a variety of activities, such as light spots, spectral spots, flares, radio and other phenomena, these phenomena are collectively referred to as "solar activity". Solar activity has a great impact on the Earth, for example, when the flare will cause the Earth's short-wave radio communications weakened or even interrupted. When the big black group from the center of the day surface area, the Earth often occurs "magnetic storm", so that the Earth's magnetic needle swaying left and right, turbulence, compass lost pointing role. Interestingly, the beautiful auroras at the north and south poles of the Earth often occur at the same time as magnetic storms. Solar activity also has a significant impact on the Earth's climate, so that the air pressure increases or decreases, so that the rainfall increases or decreases. Meteorologists are very interested in solar activity because it has a great deal to do with weather forecasting.
In short, the sun is closely related to human life on Earth. Fundamentally, the vast majority of energy on Earth comes from the sun. We eat food, vegetables, fruits grow by sunlight; we burn coal, natural gas, oil is hundreds of millions of years ago in the sunshine growth of living organisms due to crustal changes buried in the ground and formed; herbivorous animals to eat plants for life; carnivorous animals and most of them to eat herbivores for life. It can be seen that the energy of animals and plants, including human beings, is ultimately taken from the sun. Now many scientists are trying to study how to more directly utilize solar energy, because solar energy is available everywhere, inexhaustible, inexpensive, and does not pollute the environment. Nowadays, there is a wide variety of solar energy equipment, including solar stoves, solar water heaters, solar freezers, solar water pumps, solar medical equipment, solar air-conditioning units and so on. Solar cells are especially worth mentioning. It is widely used in artificial satellites and other space vehicles, so that human beings have a guarantee of energy in space exploration. The sun brings warmth and hope to mankind, and mankind will always admire and glorify the sun.