The temperature of the sun is 6000 degrees, and the earth is baking hot. Why is the space between the sun and the earth cold?

The main reason why the sun can radiate energy all the time is that the solar core is undergoing controllable nuclear fusion reaction. But the sun has warmed the earth. Why is the space temperature between the earth and the sun close to absolute zero? < / P > < p > to understand this problem, we must first find out how the sun generates energy. If we have to generalize it in one sentence, it should be: the extreme will reverse, all are forced out by gravity. Why do you say that? < / P > < p > the mass of the sun is 330000 times that of the earth, accounting for 99.86% of the total mass of the solar system, and is the absolute overlord of the solar system. Due to the huge mass of the sun, the sun’s own gravity is also very large, which will make the sun’s own extrusion very serious. As a result, the temperature of the sun’s core rises sharply to 15 million degrees. Even at this temperature, the fusion reaction can not be triggered. This is because the conditions required for nuclear fusion reactions are more stringent, at least hundreds of millions of degrees. For example, when scientists detonate a hydrogen bomb, they first detonate one. By providing a reaction temperature of hundreds of millions of degrees, scientists can trigger a nuclear fusion reaction. Due to the extremely high temperature of the solar core, the material state of the solar core is no longer the gas state, solid state or liquid state, but plasma state. The so-called “plasma state” refers to that after the electrons in the atoms of matter get enough energy, they get rid of the bondage of the atomic nucleus and become free electrons. Therefore, the solar core is more like a “porridge” of various particles, which is full of various atomic nuclei, electrons and photons. < / P > < p > this increases the possibility of nuclear encounter. However, because the nuclei are positively charged, according to the principle of repulsion of the same kind of charges, there is electrostatic repulsion between atomic nuclei, and it is necessary to overcome the “repulsive force” in order to fuse between nuclei. In principle, nuclear fusion is not possible in the sun. However, in the micro world, there is a situation called quantum tunneling. The so-called “quantum tunneling effect” refers to the reaction that can take place even if it needs energy, and it has a certain probability in the micro world. < / P > < p > but the probability is extremely low. It takes at least one billion years for a pair of nuclei to fuse. Fortunately, the sun is big enough and the number of particles is extremely large. Even if the probability is lower, it can happen in front of such a large base as the sun. The whole process is divided into three stages, and finally four hydrogen nuclei fuse into one helium-4 nucleus. < / P > < p > nuclear fusion will generate external pressure, which can compete with its own gravity, to ensure that the sun’s gravity will not force itself to collapse, which also forms a dynamic balance, so that the sun will not explode like a hydrogen bomb. There will be mass loss before and after the reaction, which will be released in the form of energy. To put it bluntly, there are photons and neutrinos in the inner core. It takes an average of 140000 years for photons to arrive at the surface of the sun from the core of the sun, and then it takes 8 minutes and 20 seconds to reach the earth. From the point of view of the micro world, the essence of temperature is the intensity of particle thermal motion. This is because everything is made up of particles, but the particles are not arranged in a neat line, but are constantly moving and disorderly. < / P > < p > scientists have found that if these particles move violently as a whole, the temperature reflected by the matter is higher. If the particles do not move violently as a whole, the reflected temperature is relatively low. < / P > < p > however, the premise is that there are enough particles. To put it bluntly, if we want to reflect the problem, we must first have enough particles. If there are no particles, in fact, we can not measure the temperature, and it is very difficult to reflect the temperature. The average density of the universe is very close to 1 * 10 ^ kg / m3, which is about the level of one cubic meter of hydrogen atom. So, when photons pass through the universe between the sun and the earth, because of the small number of particles, photons can not transfer their energy into this space. You can understand that there are no particles that receive these photons. As a result, photons are difficult to heat up space. < / P > < p > the idea that the temperature in space is absolute zero has always been a problem. As mentioned above, it is very difficult to measure the temperature of space. Second, the average temperature of the universe is minus 270.15 degrees Celsius, which is 2.7 degrees higher than absolute zero. This temperature comes from the residual temperature left by the big bang, also known as the cosmic microwave background radiation, but this temperature is difficult to measure. < p > < p > understanding why space can’t be heated, we can understand why the earth is. The earth is a celestial body of particles, with a density of 5507.85 kg / m3, 31 orders of magnitude higher than that of space. Therefore, when photons are transmitted to the earth, the particles that make up the earth can receive them well. The biggest difference between space and earth lies in the density of matter, which is 31 orders of magnitude higher than the former. If a substance is to be heated, it needs to have enough material density. Space is hard to be heated because of the open space. On the contrary, the earth will be heated because of its high material density. Continue ReadingStraight screen S20! Samsung Galaxy S20 Fe exposure: 1Hz high brush + snapdragon 865