What is the close relationship between the sun and human beings?

"Everything grows on the sun", indeed, the sun is too important, too familiar and too kind to us who take the planet in the solar system as our home. It is the center of the solar system, where it is the "king" and almost dominates everything in the solar system. However, it is so insignificant in the whole universe. In the whole universe, there are about 654.38+000 billion galaxies like the Milky Way, and there are about 654.38+020 billion stars in the Milky Way. The sun is just an ordinary member. Altair and Vega in the Milky Way are much bigger than the sun.

Since human civilization, we have been exploring and understanding the objective world, and the sun is no exception. At first, we worshipped it as a god. The ancestors of our Chinese nation regarded their ancestor Yan Di as the sun god. Later, I thought that the sky was round, and later I realized that the earth was a round ball, but for a long time it was considered as the center of the universe (Ptolemy advocated geocentric theory from BC). It was not until the 6th century AD/KLOC that Copernicus founded the Heliocentrism, including Bruno and Galileo who were brutally persecuted by the Holy See. Of course, it turns out that the sun is not the center of the universe. However, Copernicus and others made great contributions, which fundamentally shook the theoretical basis of religious theology in medieval Europe. Engels once said: "Since then, natural science has been liberated from theology."

In addition to the sun, our solar system has nine planets (there are dozens of satellites around these planets), countless asteroids and a considerable number of comets. The sun accounts for more than 98% of the total mass of the solar system (see the attached table for the main constants of the sun). The distance between the sun and the earth is about 65.438+0.5 billion kilometers, and its radius is about 696 million kilometers, which is more than 654.38+0.000 times that of the earth. The surface temperature is about 6000K, and the center temperature is above15000000 K. The structure of the sun is generally core, radiation layer, troposphere, photosphere, chromosphere and corona. We usually see its light ball.

Things always develop and change, beginning and ending. According to research, the sun was formed 5 billion years ago, and its life span is still 5 billion years (referring to the end of the main sequence star stage). Now it is in a relatively mature and stable stage, which is conducive to the existence and development of life on earth. The evolution of stars with different masses in the universe is also different. Medium-sized stars, such as the Earth, are now yellow dwarfs. After several billion years, they will become red giants, eventually white dwarfs, or even "extinguished". The earth is a member of the solar system and should share the same fate with the sun.

The sun is a huge nuclear fusion reactor, which mainly fuses hydrogen into helium, releasing huge energy. The sun shining on us with its light is the main source of the earth's energy, and the existence of the sun we feel is its radiation. Solar radiation is mainly visible light, but also infrared and ultraviolet rays. Visible light accounts for 50% of the total solar radiation, and infrared light accounts for 43%. The ultraviolet region only accounts for 7% of the energy. According to a rough estimate, the heat energy transmitted by the sun to the earth every minute is about 25 billion calories, which is equivalent to the energy generated by burning 400 million tons of bituminous coal. Under the average distance between the sun and the earth, the solar radiation energy received on the unit surface area perpendicular to the solar radiation on the upper boundary of the earth's atmosphere is 1353 W/m2, which is considerable, while the radiation energy reaching the earth's surface is attenuated to some extent due to the reflection and refraction of the atmosphere and dust, and changes with latitude. Coal and oil are solar energy preserved by biological fossils hundreds of millions of years ago, and wind energy and water power are also forms of solar energy conversion in the final analysis.

The origin of life needs energy, and so does the maintenance and continuation of life. A certain temperature condition is also a necessary condition for the survival and continuation of organisms. At the very least, water must remain liquid. The sun brings us warmth and light and provides us with necessary energy. At present, the most important utilization of solar energy is realized by photosynthesis of plants, and photosynthetic organisms are the basis of food chain. According to some data, plants on the earth fix 3× 102 1 joule of solar energy every year, which is equivalent to 10 times of all human energy consumption, and nearly 200 billion tons of organic matter are synthesized. For us humans, the organic matter continuously produced through photosynthesis is the most basic gift of the sun. Solar radiation can also help us to promote the circulation and flow of materials on the earth. Sunlight (ultraviolet rays) can kill many harmful microorganisms. Irradiating the skin can convert some nutrients we ingest into vitamin D, which is helpful for the absorption and utilization of calcium.

Nowadays, people have expanded the direct or indirect utilization of solar energy through scientific and technological equipment. The simplest one is a solar water heater, and then solar energy is used to generate electricity, and solar energy is used to drive vehicles. Sunlight is focused or can reach a very high temperature. At present, the largest parabolic reflecting condenser in the world is 9 stories high, with a total area of 2,500 square meters, and the focal temperature is as high as 4,000℃. Many metals can be melted. With the gradual depletion of fossil energy and serious pollution on the earth, scientists have great expectations for solar power plants placed on the ground or in space. Because the geostationary orbit can receive sunlight for more than 90% of the day, and there is no atmospheric barrier attenuation, it can receive 32 kW h/m2 of solar energy every day. In 1970s, NASA and the US Department of Energy put forward the plan of space solar power station, and deployed 60 solar power stations in geostationary orbit, each with a power generation capacity of 5 million kilowatts, which basically met the domestic demand for electric energy. Japan plans to send a satellite with a power generation capacity of1100,000 kilowatts into orbit about 36,000 kilometers from the earth's surface within a few years. Some scientists even imagine building a solar power station on the moon. In China, Tibet, Qinghai and other areas, the sunshine is relatively strong, and solar power generation devices on the ground have developed rapidly in recent years. With an average elevation of 4,000 meters, Tibet is the closest place to the sun in the world, with thin air, good transparency and low latitude. The annual sunshine hours are about 3,000 hours, and the annual total solar radiation is above 0/85 kcal per square centimeter/kloc. It is estimated that the energy saved by developing and utilizing solar energy in Tibet last year was equivalent to1270,000 tons of standard coal, worth about 654.38+billion yuan.

However, the sun is not good for us, and relative stability does not mean constant. Many geological and meteorological disasters on the earth are related to solar activities. On a large scale, there have been many ice ages in the history of earth's development. Every time the earth's climate gets cold, it even leads to the mass extinction of biological species. Ten thousand years ago, at the end of the last ice age, the earth's climate was relatively stable in a state that human beings were used to. In a small scale, the sunspot cycle of about 1 1.2 years has a considerable impact on the earth's climate and other aspects. The solar wind is also a kind of solar radiation, which is a stream of charged particles; With the increase of sunspots, flares and coronal material eruptions, the solar wind will be greatly enhanced and become a solar storm, which will cause changes in the ionosphere and geomagnetic field, seriously interfere with the normal work of radio communication and space equipment on the earth, damage the precision electronic instruments on satellites, cause chaos in the ground power control network, and even pose a threat to the lives of astronauts in space shuttles and space stations. Since 2000, with the increase of sunspots, solar activity has once again entered an active period. In the last ten days of September, 200 1 year, strong X-ray bursts and proton bursts occurred in the sun, reaching 1 10,000 times of the normal flow, which would have a certain impact on trans-polar short-wave communication and broadcasting. The intensification of global earthquakes in 2000 is related to the influence of solar storms on the earth's magnetic field. Some scientists compare the solar storm to the sun sneezing. When the sun sneezes, the earth often has a high fever.

Wind is a good thing, airflow can make the air composition in different areas tend to be uniform, reduce the temperature difference, spread pollen and so on, but wind disasters (tornadoes, tropical cyclones, typhoons-storm surges) often cause huge loss of life and property. Rain is also indispensable to us, but frequent floods have also seriously damaged the normal production and life of human beings.

Human factors often aggravate natural disasters. In addition to pollution, the greenhouse effect is outstanding. The increasing amount of carbon dioxide and methane in the atmosphere can block the emission of heat from the earth, just like the plastic film in the greenhouse. In recent years, government agencies and scientists all over the world are very concerned about global warming. According to observation, since the end of 19, the global average temperature has increased by 0.3~0.6℃, and there is a worsening trend. Most scientists believe that the main reason is the greenhouse effect caused by a large number of greenhouse gas emissions. In the 1990s, the global severe meteorological disasters were five times as severe as those in the 1950s, so the average annual economic losses soared from $4 billion in the 1960s to $29 billion. Experts predict that if no measures are taken, the global average temperature may rise by 100 to 5.8 degrees Celsius in the future, which will make extreme weather and climate events more frequent and seriously threaten the sustainable development of global society and economy. Climate warming will lead to sea level rise. There is a report based on the investigation of 3000 scientists, which predicts that the sea level will rise significantly in 20 10. Tuvalu, a Pacific island country, bears the brunt. In the past decade, seawater has eroded 65,438+0% of Tuvalu's land. If the global environment continues to deteriorate, within 50 years, all nine small islands in Tuvalu will disappear into the ocean and disappear from the world map forever. Besides, it will become uninhabitable earlier. For this reason, Tuvalu's leaders are considering the possibility of relocating the whole country. According to reports, a research report recently published by the Pew Center for Global Climate Change in the United States estimates that by the end of this century, global temperature rise will make ice in polar regions and snow and glaciers in mountainous areas melt continuously, which will lead to sea level rise 17-99 cm. In that case, the rich southeast coast of China will be seriously affected. The increase of average temperature will significantly affect the distribution of species, and many species will accelerate extinction and destroy the ecological environment. Since the 20th century, due to human activities and other reasons, the ozone layer over the earth has become thinner and hollowed out, and the ultraviolet rays in solar radiation have lost their blocking, reaching the ground in large quantities, and humans and creatures will be harmed by excessive ultraviolet rays.

Indeed, we humans have no ability to change the laws of the evolution of the universe, nor can we change the birth, illness, death, joys and sorrows of the sun. Some scientists imagine that in the distant future, when the earth is overpopulated or the earth environment becomes unfit for human habitation, they can emigrate to other planets. Even if it is possible, it is only a last resort. Today, we must face the reality, further study the sun, learn more about its reality and laws of motion, seek advantages and avoid disadvantages, and make better use of it. For example, there should be many possibilities for the utilization of solar energy, including the use of biotechnology to transform the photosynthetic capacity of algae and plants (the utilization rate of light energy by crops is generally only a few percent now). At the same time, take measures to avoid its harm, strengthen the observation of solar activities, and improve the forecasting level of meteorological and geological disasters; In particular, it is necessary to reduce greenhouse gas emissions and protect and restore the ozone layer.