The water formation process of the earth
The earth is the only planet covered with liquid water among the eight planets in the solar system.
There are great differences in academic circles about the origin of water on the earth, and there are dozens of different theories of water formation at present. Some people think that in the early days of the earth's formation, hydrogen in the primitive atmosphere was oxidized into water, and water vapor gradually condensed to form the ocean; There is also a view that water originally existed in the nebula material that formed the earth.
Other scientists believe that silicate reacts with other substances in the original crust under the influence of volcanoes to precipitate water. There are also views that comets and meteorites attracted by the earth are the main sources of water on the earth, and even the water on the earth is still increasing.
When we open the map of the world, when we face the earth, most of the areas in front of us are bright blue. Looking at the earth from space, the earth we live in is an oval and extremely beautiful blue sphere. Water is the most abundant natural substance on the earth surface, covering more than 7 1% of the earth surface. The earth is a veritable water polo.
There are two main views on the source of the earth's water.
Autogenesis theory
1. After the earth condensed into a planet from the primitive nebula, due to the internal temperature change and gravity, the matter differentiated and convected, so the earth gradually differentiated into a sphere. In the process of differentiation, hydrogen and oxygen float to the surface, and then generate water through various physical and chemical actions;
2. When basalt first melts and then cools to form the original crust, water will be produced. At first, the earth was a cold sphere. Since then, radioactive elements such as uranium and thorium existing in the earth have begun to decay, releasing heat energy. As a result, the substances in the earth began to melt, the substances with high melting point sank, and the substances easy to melt rose, from which volatile substances were separated: nitrogen, oxygen, carbohydrates, sulfur and a lot of water vapor. Experiments show that when 1 m3 granite melts, 26 L of water and many completely volatile compounds can be released.
3. The magma deep underground is rich in water. Experiments show that magma with pressure of 65438±05 kPa and temperature of 65438 00000℃ can dissolve 30% water. The average water content of volcanic magma is 6%, and some of them can reach 12%. The deeper the earth is, the higher the water content is. Some people speculate that in the 4.5 billion years of the earth's existence, the water released by deep magma can reach half of the modern global ocean water.
4. Volcanic eruption releases a lot of water. Judging from modern volcanic activity, almost every volcanic eruption has more than 75% water vapor ejected. 1906, the column of pure water vapor erupted by Mount Vesuvius was as high as13000m, which lasted for 20 hours. There are thousands of natural steam vents in the s000mokes valley in the Katmai volcano area of Alaska, which can spray steam and hot water at 97 ~ 6,450℃ at an average speed of about 23,000 meters per second. . Some people think that in the whole history of the earth, the total amount of solid matter thrown by volcanoes is half of the whole lithosphere, and the water ejected by volcanoes can also account for half of the modern global ocean water;
5. The minerals in the earth dehydrate and decompose some water, or the released gases such as carbon monoxide and carbon dioxide react with hydrogen at high temperature to generate water. In addition, the combustion of hydrocarbons will also produce water. In hard igneous rocks, there are also some inclusions of crystal water and primitive water.
Exogenous theory
1. When people study the composition of chondrites, they find that they contain a certain amount of water, generally 0.5 ~ 5%, and some as high as 10%, while carbonaceous chondrites contain more water. Chondrite is the most common meteorite in the solar system, accounting for about 86% of all meteorites. It is generally believed that chondrites are the earliest condensate of the primitive sun, and the earth and other planets in the solar system are condensed from these chondrites;
2. The solar wind reaches the earth's upper atmosphere, bringing a large number of hydrogen, carbon, oxygen and other nuclei, which combine with electrons in the atmosphere to form hydrogen, carbon and oxygen atoms. It is estimated that 1.5 t is produced almost every year in the upper atmosphere of the earth. Cosmic water? . Then, the water falls to the earth in the form of rain and snow.
Importance of protecting water resources
Water is the source of life for all things on the earth, the basic condition for human survival and development, an extremely important and active factor in the natural and social environment, and an irreplaceable basic natural and strategic resource for maintaining the function of the earth's ecosystem and supporting the development of social and economic systems.
At present, more than half of the countries and regions in the world lack drinking water, especially in developing countries, with a total of about 654.38+07 billion people without clean water. There are many people in China who don't need clean water, and even drinking water has become the primary problem. Some time ago, the difficulty of drinking water caused by the continuous drought in southwest China made people realize the problem of water safety.
Therefore, we should face up to reality, pay attention to water security, examine and treat water security issues from a global, strategic and long-term perspective, adhere to the Scientific Outlook on Development, respect the laws of nature, economy and society, correctly handle various relationships between people, people and society, and people and nature, strengthen the construction of a resource-saving and environment-friendly society, vigorously develop a circular economy, meet demand, develop water, save and protect, and develop scientifically. The sustainable utilization of water resources ensures the sustainable development of society, economy and ecology and promotes the construction of a harmonious society.
Water, air and food are the three elements of human life and health. Water is the blood of all life and environment, not only the source of human life, but also the main factor of natural ecological environment. Through the circulation of water in the ecosystem, the self-balance of the natural ecosystem can be effectively maintained. Water is also the lifeline of economic development and social progress, and an important material basis for sustainable development. No matter in the era of nomadic tribes, or in the farming society, no matter today or in the future society, water will always be an indispensable and irreplaceable resource. Man lives by water and develops by water. Water keeps human beings alive and promotes the birth and development of social civilization. The evolution of civilization gives water more luster and aura. People can't live without water, and neither can the ecological environment. Without water, there would be no human society today, let alone building a harmonious society.
Water security is not only affected by natural factors, but also by human factors. With the intensification of human activities, the problem of water security has become more prominent. The water security problems we are facing at present are not only determined by natural conditions, but also caused by human activities.
In fact, judging from the results of the national water resources survey and evaluation in the early 1980s and recently, the average total amount of water resources in China has not changed much for many years. It should be said that the threat of water security comes more from people's own behavior. Uncontrolled water demand, polluted water and wasted water pose a great threat to water security. Most of these problems are caused by human beings themselves. To solve the problem of water security, human beings need strict self-discipline, respect for nature, treat nature well, protect nature, act in strict accordance with natural economic and social laws, build a harmonious society, standardize human activities, take the road of sustainable development, and achieve man and nature, man and society.
Looking at the rise and fall of many ancient civilizations, we find that these civilizations went from prosperity to decline because they rarely or never followed the ecological laws in the process of civilization development, and wantonly exploited and plundered nature, which led to the collapse of the natural ecosystem and eventually led to the decline of civilization. Today, we are more aware of the threat of climate change than ever before. If we don't change our behavior and go our own way in front of nature, then hundreds of years later, huge heat waves will sweep every corner of the earth, icebergs floating in the ocean will melt without a trace, and global tragedies will come unexpectedly. Therefore, we should change from predatory, conquering and polluting industrial civilization to harmonious, restorative and constructive ecological civilization, save and protect water resources, make people live in harmony with nature and promote the all-round development of human society.
In recent years, with the rapid development of China's social economy and the influence of human activities, people have plundered nature without restraint, resulting in some bad phenomena, such as water competition between people, regions, people and ecological environment, pollutants and ecological environment, sewage and rivers, and people and land. As a result, water resources are decreasing, pollution is increasing, water bodies are weakened or lose their normal functions, and social and economic values cannot be maintained. It changes the balance of hydrological cycle, reduces the water quality, and directly affects the basic needs of human beings for water. The consequences of this action are hidden, extensive and lagging. When the long-term cumulative effect exceeds the tolerance threshold, it will endanger the normal operation and virtuous circle of the natural environment and socio-economic system, and then trigger a series of water security problems. While preventing water from harming people, we should also prevent people from harming water. If people don't control water in time, water will do more harm to people. The problem of water resources is related to the national economy and people's livelihood and has a wide range of sociality. Water conservancy work involves all aspects, contradictions are intertwined and the situation is complicated. Therefore, it is necessary to correctly handle the relationship between economic development, social development and people's all-round development, the relationship between development speed and structure, quality and benefit, the relationship between economy and society and population, resources and environment, the relationship between people, regions and regions, people and nature, parts and whole, immediate and long-term, contemporary and future, and make overall plans to solve the deep-seated social contradictions that hinder and affect environmental and resource problems in society. Eliminate the discrimination between classes, races and even countries in terms of resources and environment, realize the harmony between man and nature, safeguard the fairness among contemporary people, between contemporary people and future generations, and between people in different regions, develop water quantity and water use, make economic and social development adapt to the carrying capacity of water resources and water environment, and make the whole society embark on the civilized development path of production development, affluent life and good ecology.
The meaning of water
Water (h? O) It is an inorganic substance composed of hydrogen and oxygen, and it is a colorless and odorless transparent liquid at normal temperature and pressure. Water is one of the most common substances, an important resource for all life, including human beings, and the most important component of organisms. Water plays an important role in the evolution of life. People's understanding of aquatic products has a long history. In the simple material view of ancient East and West, water was regarded as the basic component, and water was one of the five elements in ancient China. There was also water in the four-element theory of ancient western countries.
water culture
In the early days of civilization, people began to explore the composition or classification of various things in the world, in which water played an important role. The four elements put forward by the ancient west said that there was water; There are also water in the four major Buddhists; In China's ancient theory of five elements, water represents all liquids and things with flowing, moist and feminine properties.
In human childhood, water has the ability to nurture and destroy, and its unpredictable temperament produces feelings of love and fear, which leads to water worship. By endowing water with the spirit of God, we pray that water can bring peace, harvest and happiness to mankind. There is Heshui Zuo's word "Broken Son"? River water:? It is easier to break a dam than to climb a cliff. The exhibition is always quiet, connected with everything, and occasionally rushes into the ravine. Carrying a boat will also overturn it. . Pieces of smoke and green fields are surging with the fluid source of life. Never abandon pollution and live with it. Never be insatiable and arbitrary. Trouble is also trouble. ?
The traditional Dragon King in China deified water. Where there is water, there is the Dragon King, whose temples and churches are all over the country. Sacrificing the Dragon King and praying for rain are traditional beliefs and customs in China.