The sun continuously radiates energy to the earth every day. The essence of life on earth is also dependent on the energy radiated by the sun, but in fact, the energy received by the earth from the sun itself only accounts for a very small part of the energy radiated from the sun. , which is 1/2.2 billionth of the total radiant energy emitted by the sun into the universe, but even this small part is enough for everything on the earth to grow.
The value of the solar constant announced by the World Meteorological Organization in 1981 is 1368 watts/square meter. The solar radiation passes through the atmosphere, and part of it reaches the ground, which is called direct solar radiation; the other part is absorbed and scattered by the molecules of the atmosphere, dust and water vapor in the atmosphere. and reflection. Part of the scattered solar radiation returns to space, and the other part reaches the ground. The part that reaches the ground is called scattered solar radiation. The sum of scattered solar radiation and direct solar radiation reaching the ground is called total radiation. After the solar radiation passes through the atmosphere, its intensity and spectral energy distribution change.
The solar radiation energy reaching the ground is much smaller than the upper boundary of the atmosphere. After atmospheric absorption and reflection, the surface can receive about 1,000 watts per square meter, and the total amount received by the earth is about 11 billion kilowatt-hours. And let's assume we can cover the entire surface of the earth with solar panels. Then the power generation in one year is about 1 billion kWh. In 2016, the world's total power generation was 25 trillion kWh. It is 1/40,000th of the solar energy that the earth receives.
Why does the earth's temperature remain in equilibrium?
The temperature change of the earth depends on the characteristics that other planets do not necessarily have, such as atmosphere, ocean currents, and suitable rotation speed, and maintains a relatively stable interval. The angle between the orbital plane revolving around the sun and the earth’s axis itself, the northern and southern hemispheres receive different solar radiation at different times, so the temperature in the north will drop to minus 30 degrees Celsius in winter, and it can be as high as 30 degrees Celsius in summer, and 60 degrees in the middle. The difference between degrees, considering the huge size of the earth, the energy received and lost is very huge; at the same time, there will be a relatively obvious temperature difference between day and night in a region, this is because the part of the earth that is not illuminated by the sun at night will radiate to the universe energy, thereby reducing the temperature. Therefore, the temperature of the earth is changing all the time, and this change is precisely because of the fluctuation of the energy received and released by the earth, which does not violate the law of conservation of energy.
For more than four billion years, the earth has been bathed in the brilliance of the sun, and the sun generously radiates energy to the earth every moment. According to a general understanding, the earth should be getting warmer and even hotter. However, in fact, the earth has not become warmer. In the long years of the earth, it has also encountered four ice ages. The earth is along: cold - warm - cold - then warmer - colder... again and again, cycle Reciprocating and never getting hot!
Where does the energy radiated from the sun to the earth go? All objects with temperature can produce radiation, high temperature objects radiate visible light and ultraviolet (short wave), and low temperature objects radiate infrared (long wave). The high surface temperature of the sun radiates ultraviolet and visible light to the earth, and the low surface temperature of the earth radiates infrared rays to the universe! The earth maintains climate change, and it consumes energy to rotate and revolve around the sun, and a very small amount of energy is converted into coal, oil and natural gas for energy storage Up, in the long billions of years, a kind of dynamic equilibrium is basically reached, so the surface temperature of the earth is almost constant for a long time!
Consumption of fossil energy leads to global warming
Fossil energy refers to coal, oil, natural gas, etc. formed by living organisms over hundreds of millions of years. It is a non-renewable energy source. They are all evolved from the remains of plants and animals hundreds of millions of years ago. All fossil fuels are composed of hydrocarbons. , fossil fuels currently account for 80% of the industrial world's energy sources. Although fossil energy is pitifully insignificant compared to solar energy, the amount of heat and carbon dioxide produced by fossil energy, which has been stored for billions of years and consumed by humans for hundreds of years, is also staggering, which may destroy Existing climate balance.
People burning fossil fuels, such as oil, coal, etc., will produce a large amount of greenhouse gases. These greenhouse gases are highly transparent to visible light from solar radiation, but are highly absorbing to long-wave radiation emitted by the earth, and can strongly absorb ground radiation. Infrared rays in the earth, causing the earth's temperature to rise, that is, the greenhouse effect. Global warming will redistribute global precipitation, melt glaciers and permafrost, and rise sea levels, which not only endangers the balance of natural ecosystems, but also threatens human survival. The emission of greenhouse gases on land has caused the temperature of the continent to rise, and the temperature difference between the continent and the ocean has become smaller, which has slowed down the air flow, and the smog cannot be blown away in a short time. Today, our planet is hotter than it has been in the past 2,000 years, and if the situation continues to deteriorate, by the end of this century, Earth's temperature will climb to a 2-million-year high.
Solar power won't disrupt Earth's temperature balance
Solar power generation is a device that directly converts solar energy into electrical energy using battery components or thermal energy machines. It does not consume fossil fuels. In the earth's temperature balance system, it does not generate more energy; solar power plants are built on the roof and ground, and there is no greenhouse. Gas emissions will not affect the external radiation of the earth; solar power plants are generally built on land that cannot be planted, so it will not affect the absorption of light energy by other green plants (including algae) on the earth.