Who has information about the sun?

The sun is a hot gas planet, and it glows and heats itself. Its surface temperature is about 6000 degrees Celsius, and its center temperature is as high as150,000 degrees Celsius. The radius of the sun is about 696,000 kilometers, which is about 109 times that of radius of the earth. Its mass is 1.989× 1027 tons, which is about 332000 times that of the earth. The average density of the sun is1.4g per cubic centimeter, which is about 1/4 of the density of the earth. The average distance between the sun and the earth is about1.500 million kilometers.

The sun is an ordinary star in the Milky Way, located on the spiral arm of Orion, north of galactic plane, about 2.3 light years away from the center of the Milky Way. It rotates around the center of the Milky Way at a speed of 250 kilometers per second, and it takes about 250 million years to make a revolution. The sun is also rotating, and its cycle is about 25 days in the equatorial belt; The polar region is about 35 days.

Through the analysis of the solar spectrum, we know that the chemical composition of the sun is almost the same as that of the earth, but the ratio is different. The most abundant element in the sun is hydrogen, followed by helium, carbon, nitrogen, oxygen and various metals.

The structure of the sun

From the inside out, the structure of the sun is mainly divided into: the central thermonuclear reaction zone, the radiation layer outside the core, the troposphere outside the radiation layer and the solar atmosphere outside the troposphere.

Inferred from the theory of nuclear physics, the center of the sun is a thermonuclear reaction zone. The central area of the sun accounts for 1/4 of the entire solar radius, which is about half of the entire solar mass. This shows that the material density in the central region of the sun is very high. It can reach 0/60 grams per cubic centimeter/kloc. The central area of the sun is in a state of high density, high temperature and high pressure under the attraction of its own strong gravity. It is the birthplace of the great energy of the sun.

The energy generated in the central region of the sun is mainly transmitted by radiation. Outside the central area of the sun is the radiation layer, which ranges from 0.25 solar radius at the top of the central area of the thermonuclear to 0.86 solar radius, and the temperature, density and pressure decrease from the inside out. In terms of volume, the radiation layer accounts for the vast majority of the whole solar volume.

In addition to radiation, the energy inside the sun spreads outward, and there is also a convection process. That is, from the solar radius of 0.86 to the bottom of the solar atmosphere, this interval is called the troposphere. The properties of this layer of gas vary greatly and are unstable, forming obvious up-and-down convection movement. This is the outermost layer of the inner structure of the sun. Outside the troposphere is the solar atmosphere. The solar atmosphere can be divided into photosphere, chromosphere and corona layer from inside to outside. What we see is the dazzling sun, which is the intense visible light emitted by the photosphere in the solar atmosphere. The photosphere is located outside the troposphere and belongs to the lowest or innermost layer of the solar atmosphere. The thickness of the photosphere is about 500 kilometers, which is like the ratio of human skin to muscle relative to the radius of the sun of about 700 thousand kilometers. When we say that the average temperature of the sun is about 6000 degrees Celsius, we mean this layer. Beyond the ball of light are colored balls. Usually, due to the strong photosphere scattered by the earth's atmosphere, chromosphere is submerged in the blue sky. Only during the total solar eclipse will you have a chance to directly appreciate the red appearance of the colored ball. The solar chromosphere is a plasma layer full of magnetic field, about 2500 kilometers thick. Its temperature rises gradually from the inside out, the part connected with the top of the photosphere is about 4500 degrees Celsius, and the outer layer reaches tens of thousands of degrees Celsius. The density decreases with the increase of height. The whole structure of chromosphere is uneven. Due to the instability of the magnetic field, the upper atmosphere of the sun often explodes and flares occur.

The corona is the outermost layer of the solar atmosphere. The material in the corona is also plasma, the density is lower than that of chromosphere, and the temperature is higher than that of chromosphere, reaching several million degrees Celsius. During the total solar eclipse, very bright silvery white light can be seen around the surface of the sun, which is the corona.

The energy of the sun

Apart from atomic energy, volcanoes and earthquakes, solar energy is the total source of all energy on the earth. So, how much did the whole earth receive? The sun emits a lot of energy? Scientists imagine putting an instrument to measure the total solar radiation energy outside the earth's atmosphere. The total energy of solar radiation received per square centimeter per minute is 8.24 Joules. This value is called the solar constant. If the sun constant is multiplied by the spherical area with the radius of the average distance between the sun and the earth, the total energy emitted by the sun per minute is about 2.273× 1028 joules per minute. The earth only receives 2.2 billion of this energy. The energy that the sun sends to the earth every year is equivalent to 654.38+000 billion kWh. Solar energy is inexhaustible and pollution-free, and it is the most ideal energy source.

sun spot

Observing the sun through ordinary optical telescopes, we observe the activities of the photosphere (the innermost layer of the sun's atmosphere). You can often see many black spots on the photosphere, called sunspots. The size, number, location and shape of sunspots on the sun's surface are different every day. Sunspot is a local strong magnetic field formed by the violent movement of photosphere, and it is an important symbol of photosphere activity. Long-term observation of sunspots will show that there are many sunspots in some years, few sunspots in some years, and sometimes there are no sunspots in the sun for several days or dozens of days. Astronomers have long noticed that there is an interval of 1 1 year from the year with the most (or least) sunspots to the next year with the most (or least) sunspots. In other words, the average activity period of sunspots is 1 1, which is also the activity period of the whole sun. Astronomers call the darkest year of the sun "the peak year of solar activity" and the year with the least sunspots "the quiet year of solar activity".

solar flare

Solar flare is one of the most intense solar activities. It is generally believed that it happened in chromosphere, so it is also called "color ball explosion". Its main observation feature is that the rapidly developing bright spot suddenly appears on the surface of the sun (often above the sunspot group), and its life span is only a few minutes to tens of minutes, and its brightness rises quickly and declines slowly. Especially at the peak of solar activity, flares appear frequently and become stronger.

Although it is only a bright spot, once it appears, it is simply an earth-shattering explosion. The energy released by this brightness enhancement is equivalent to the total energy of 6.5438+million to 6.5438+million strong volcanic eruptions, or equivalent to the explosion of tens of billions of 100-ton hydrogen bombs; However, a large flare burst can release huge energy of 10 ~ 25 Joules within 120 minutes.

In addition to the local sudden brightening of the solar surface, the flare is mainly characterized by the sudden increase of radiation flux from radio band to X-ray; Flares emit a wide range of radiation, including ultraviolet rays, X-rays and gamma rays, infrared rays and radio emissions, shock waves and high-energy particle streams, and even cosmic rays with extremely high energy.

Flare has a great influence on the space environment of the earth. When the chromosphere exploded, the earth's atmosphere immediately echoed. When a flare breaks out, when a large number of high-energy particles reach the earth orbit, it will seriously endanger the safety of astronauts and instruments in the spacecraft. When the flare radiation approaches the earth, it will collide violently with atmospheric molecules, destroying the ionosphere and making it lose the function of reflecting radio waves. Radio communication, especially short-wave communication, as well as television and broadcasting, will be disturbed or even interrupted. The high-energy charged particle stream emitted by flare interacts with the upper atmosphere of the earth, producing auroras, disturbing the earth's magnetic field and producing magnetic storms.

In addition, flares have direct or indirect effects on meteorology and hydrology to varying degrees. Because of this, people pay more and more attention to the detection and prediction of flare bursts, and try to uncover the mystery of flare maze.

Legend has it that during World War II, one day, the war in front of Germany was tight, and the operator in castle wolfenstein in the rear was busy manipulating the radio and delivering orders. Suddenly, the sound in the earphone disappeared. He checked the machine and the radio station was intact; Turning the knob to change the frequency still doesn't help. As a result, the front line advanced contact and fell into leaderless chaos, and the battle ended in failure. Brooke was sentenced to death by a military court. He shouted "wronged! Hey! " Later, it was found out that the "culprit" of the radio interruption was a flare. Brooke's death is really wrong. He died because people didn't know the flare at that time.

Spot (spectral spot)

Spotted tissue on the photosphere of the sun that is brighter than the surrounding area. When observing with an astronomical telescope, it is often found that the surface of the photosphere is bright and dark. This bright and dark spot is formed because of the different temperatures here. The darker points are called "sunspots" and the brighter points are called "sunspots". Sunspots often "perform" on the edge of the sun's surface and rarely appear in the central area of the sun's surface. Because the radiation in the central area of the sun's surface belongs to the deep gas layer of the photosphere, and the light at the edge mainly comes from the higher part of the photosphere, the light spot is higher than the sun's surface and can be regarded as a "plateau" on the photosphere.

Sunspots are also strong storms on the sun, which astronomers call "plateau storms". However, compared with the ground storm with dark clouds rolling and heavy rain and strong winds, the character of "plateau storm" is much gentler. The brightness of the light spot is only slightly stronger than that of the quiet photosphere, generally only10%; The temperature is 300℃ higher than that of the quiet photosphere. Many sunspots have an indissoluble bond with sunspots, and they often "perform" around sunspots. A small number of sunspots have nothing to do with sunspots, and are active in the 70 high latitude area, with a relatively small area. The average life span of spots is about 15 days, and the life span of larger spots can reach three months.

The light spot not only appears in the photosphere, but also has its activity place in chromosphere. When it "performs" on the color ball, the position of the activity is roughly the same as when it appears on the light ball. However, what appears on the color ball is not a "light spot", but a "spectral light spot". In fact, the light spot and the spectral spot are the same whole, just because their "resident" heights are different. It's like a building, where the light spot lives downstairs and the spectrum spot lives upstairs.

Texture structure

Texture is a kind of solar surface structure on the solar photosphere. It is in the shape of polygonal particles, which can only be observed with astronomical telescopes. The temperature of granular tissue is about 300℃ higher than that of intergranular region, so it is bright and easy to see. Although it is a small particle, the actual diameter is 1000 km-2000 km.

The structure of bright particles is probably a hot air mass rising from the troposphere to the photosphere, which does not change with time and is evenly distributed, showing violent fluctuation. When the texture rises to a certain height, it will soon become cold and immediately drop along the gap between the rising hot air currents; Life expectancy is also very short, and it comes and goes in a hurry. From appearance to disappearance, it is almost faster than clouds in the earth's atmosphere, with an average life span of only a few minutes. In addition, the super-granulation discovered in recent years has a scale of about 30,000 kilometers and a life span of about 20 hours.

Interestingly, while the old rice tissue disappeared, the new rice tissue quickly appeared in the original position. This persistent phenomenon is like the hot bubbles rolling up and down on the boiling rice porridge we see every day.

Solar activity-prominence

Prominence is a kind of solar activity phenomenon that protrudes beyond the edge of the sun's surface. When prominence appears, colored balls in the atmosphere resemble burning grasslands, and rose-red tongue-shaped gas rises like fire, with different shapes, some like clouds, some like arch bridges, some like fountains, some like clumps of grass, and some are as beautiful as festive fireworks. On the whole, they are shaped like earrings attached to the edge of the sun, hence the name "prominence".

Prominences rise about tens of thousands of kilometers. Large prominences can be hundreds of thousands of kilometers higher than the surface of the sun, with a general length of about 200,000 kilometers, and individual prominences can reach 1.5 million kilometers. Prominences are much darker than the photosphere, so they can't be observed with the naked eye at ordinary times, and can only be seen directly during a total solar eclipse.

Prominence is a very strange phenomenon of solar activity. Its temperature ranges from 5,000 to 8,000, and most prominences rise to a certain height and then slowly descend to the sun. However, some prominences float in the lower corona, and the temperature is as high as 2 million K, so they don't attach or disintegrate, just like a piece of unmelted ice in a hot steelmaking furnace. In addition, the density of prominence is 654,330 higher than that of corona.

surfing

Surfing is also called "solar wave". An ejection phenomenon of solar photospheric matter. It usually occurs over sunspots and has strong reproducibility. When a broken wave falls behind along the rising path, it will trigger a new broken wave to take off, and so on, but the scale and height are getting smaller and smaller every time until it disappears.

Surfing at the edge of the sun looks like a bright hill with a sharp peak at the top. The height of the rise is different. Small surfing is only a few hundred kilometers, big surfing can reach 5000 kilometers, and the maximum surfing can reach 1 ~ 20000 kilometers. The maximum speed of the projectile can reach 100 ~ 200 kilometers per second, which is more than 100 times faster than the fastest reconnaissance plane. When they reach the highest point, they begin to descend under the influence of the sun's gravity until they return to the surface of the sun. From the high-resolution observation data, it is found that surfing is composed of a very small bundle of fibers, and each bundle of fibers is very small apart, which shines and moves together as a whole.

needle

There are numerous needle-like high-temperature plasma prominences on the chromosphere. Looking at the edge of sun gear, we can see many tiny and bright "flames", just like clusters of burning grass on the surface of the sun. The width of the needle is about 800 kilometers, the height is 4400 ~ 9800 kilometers, and the average life span is about 5 minutes.

In central chromosphere, the number of needles is about 250,000; At a distance of 3,000 kilometers from the sun, it was reduced to 93,000; There are only about 200 kilometers away from Sun 1.5. The needle is ejected from the color ball at a speed of about 25 kilometers per second. Some of them rose at a constant speed, some jumped to a certain height and began to fall under the influence of the sun's gravity.

In the mid-1970s, the "Sky Lab" launched by the United States discovered the phenomenon of super needles, with a width of 10.8 million kilometers and a height of 43,000 kilometers, all of which are10 times larger than ordinary needles. Supernovae can rise to a height of 35,000 kilometers, wander around the corona for a period of time, and then fall back to chromosphere and stay for 40 minutes.