1. Human activities and solar radiant energy
Everything grows by the sun. The energy needed for human production and life, such as oil, coal, wind energy, ocean tidal energy, hydropower, geothermal energy, biomass energy, combustible ice, etc., which are well known and used by people, are all forms of transformation of solar radiant energy on the earth. With the increase of the population, the carbon dioxide emitted by humans due to the excessive use of fossil fuels has exceeded the absorption capacity of the earth’s ecosystem. Ecological overload has also led to shrinking forests, decline of fishery resources, land degradation, reduction of freshwater resources, increasing loss of biodiversity, and serious air pollution. According to statistics from the World Wide Fund for Nature, humans only consumed about 2/3 of the earth’s annual renewable resources in 1961. The “Earth Living Force Report 2012” shows that humans currently consume 1.5 earth’s ecological resources each year, and will reach 2 earths by 2050. China’s ecological situation is also not optimistic. Although China’s per capita population is lower than the global average and much lower than European and American countries, it is already 2.5 times its own biological capacity, which means that 2.5 Chinese natural resources are needed to meet demand; at the same time, due to the large population base, China’s total ecological footprint is the largest in the world, and China’s fragile ecosystem is under the dual pressure of economic development and growing population.
By switching to clean and sufficient renewable resources (such as solar energy, wind energy, etc.), it is possible for us to gradually reduce polluting emissions that pollute the air in order to alleviate the impact of climate change on the planet. The use of atomic energy has also matured, but the leakage of the Chernobyl nuclear power plant and the harm of the Fukushima nuclear leak in Japan have caused fear. Earthquakes, volcanic eruptions, floods and other energies generated by crustal movement are also being recognized by people.
Solar photovoltaic power generation is the most flexible and convenient way to develop and utilize solar energy, and it has developed rapidly in recent years.
2. Solar radiant energy
Solar radiant energy refers to the solar radiant energy that reaches the upper boundary of the earth’s atmosphere, also known as astronomical solar radiation, or solar energy for short. The solar radiation energy received by the earth is only 1/2.2 billionth of the total radiation energy emitted by the sun into space. The sun is the closest celestial body to the earth that emits light by itself. It brings light and heat to the earth. The sun’s activity comes from its central part, where the central temperature is as high as 1500×106 ℃, where nuclear fusion takes place. Solar energy is the energy produced by the continuous nuclear fusion reaction process inside the sun. Fusion produces energy and is released to the surface of the sun, emitting light and heat through a process of convection. It takes millions of years for the energy in the core of the sun to reach its surface and enable the sun to shine. So far, the age of the sun is about 4.6 billion years, and it can continue to burn for about 5 billion years. According to the current cosmological theory, in the final stage of the existence of the sun, the helium in the sun will be transformed into a heavy element, and the volume of the sun will begin to expand until it engulfed the earth. After 100 million years of the red giant phase, the sun will suddenly collapse into a white dwarf star-the last stage of the existence of all stars. After several trillion years, it will eventually cool down completely. Therefore, for mankind, solar energy is an inexhaustible and inexhaustible energy source.
