Xingyun said: Immanuel Kant first proposed the nebula hypothesis of the origin of the solar system.

Pierre-Simon Laplace also independently put forward the nebula hypothesis about the origin of the solar system.

catastrophism

theory of capture

It is generally believed that the solar system was formed by a nebula gradually condensed by its own gravity about 4.6 billion years ago, and it is a celestial system formed by many celestial bodies arranged in a large range according to certain rules. The members of this sun kingdom include a star, nine planets, at least 63 satellites, about one million asteroids and countless comets.

The nine planets are the main members of the solar system, and the order of distance from the sun is: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. They all run around the sun in the same direction from west to east on almost graphic orbits close to the same plane. Except Mercury and Venus, all nine planets are accompanied by natural satellites, and the total number of satellites detected in the solar system is about 68. Jupiter, Saturn, Uranus and Neptune all have rings.

The eight planets in the solar system are, from left to right, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. form

In our galaxy, there are about 200 billion different kinds of stars. Although complex, it runs in a certain order. About 4.6 billion years ago, somewhere in the Milky Way, a supernova exploded. The explosion triggered a strong shock wave, which spread to the whole interstellar cloud, resulting in uneven density of interstellar cloud. A certain part of the interstellar cloud increases in density and finally begins to shrink, forming the original solar system nebula. In the process of continuous contraction, the temperature of the central part gradually increased, and the primitive sun was born. The primitive solar system nebula began to revolve around the primitive sun like a disk.

When the contraction ends, the primitive solar system nebula begins to cool, and mineral particles also condense and precipitate on the equatorial plane of the disk. Then, the mineral particles split into many lumps, forming countless "micro-planets" with a diameter of about 10 km. Micro-planets collide and merge violently again and again, some are smashed, some are smashed into a ball and gradually develop into primitive planets. In this way, a solar system with nine planets was born.

The solar system refers to the sun and some nearby planets, satellites and comets, as well as many interplanetary substances such as asteroids, particles and gases.

Britain put forward a new hypothesis of planetary formation, and the formation of the solar system is not representative.

In the past 10 years, astronomers have discovered hundreds of planets in extrasolar galaxies. The latest research by British scientists shows that the formation process of these planets may be different from that of planets of the solar system, such as the Earth, and that the traditional hypothesis of planetary formation is not perfect.

Based on the traditional planetary formation hypothesis summarized by the solar system, it is believed that the dust in the air around the stars gradually gathers into rocks, and these rocks eventually become the nuclei of the planets, and then the nuclei attract the atmosphere. According to the latest issue of the British magazine "New Scientist", scientists at the University of Leicester in the United Kingdom have found that this hypothesis cannot fully explain the formation process of extrasolar planets discovered in recent years.

These planets are much bigger than Jupiter, but they are closer to their orbiting stars than the sun and the earth. According to the traditional theory of planetary formation, these planets will "fall" into the stars under the action of gravity during their formation. In addition, the orbits of these planets tend to be elliptical, while the orbits of planets such as the earth are more similar to circles.

Researchers speculate that the formation process of planets of the solar system may not be representative, and the formation process of extrasolar planets may be: the dust around the stars in the galaxy is unstable and suddenly falls apart into pieces. Each piece of debris collapses under its own gravity to form a planet. The scientist in charge of this research said in an interview that the solar system may be unique in the Milky Way.

However, experts also pointed out that due to the limitations of astronomical observation methods, it is not yet possible to draw a conclusion on this issue. To truly understand whether the formation process of planets of the solar system is special or not, it needs longer observation time.

Can humans find a living base outside the earth? This is a very attractive and eternal question. A research team composed of international astronomers has found new clues for this. They reported in the February 15 issue of Science that they discovered another planetary system similar to the solar system, in which Jupiter and Saturn are vividly visible, while other planets in suitable positions still need to be located.

Where is it?

This planetary system named OGLE-2006-BLG- 109L is like a miniature version of the solar system, where the two gas planets are like Jupiter and Saturn of the same scale.

According to the report, this is a surprise, which shows that planetary systems similar to the solar system are more common in the universe. Humans are more hopeful to find extraterrestrial life and establish an extraterrestrial survival base.

This galaxy is about 5000 light years away from the earth. The newly discovered "solar system" has a miniature version of the "sun", which is only half the size of the sun. Of the two planets, the smaller planet is about twice as far from its star as the larger planet is, just as Saturn is twice as far from the sun as Jupiter. It is estimated that the mass of Little Jupiter is 70% of that of Jupiter, and that of Little Saturn is 90% of that of Saturn.

Although this star is much darker than the sun, the temperatures on the two planets are likely to be similar to Jupiter and Saturn because they are closer to the star. The research team also believes that there may be terrestrial planets (that is, rocky planets) similar to Earth and Mars closer to this "little sun".

How to find out?

The global astronomical network consisting of 1 1 telescopes has verified this new discovery, including the famous Liverpool telescope in Britain. This discovery also benefited from the "gravitational microlens" technology. The principle of this technology is as follows: if another star passes between a distant star and the earth telescope, the gravity of the intervening star will amplify the incident light of the distant star like a lens; When the planet revolves around the nearest star, the planet's gravity will also have a certain impact on light. By studying the changes of light, scientists discovered the existence of related planets.

This theory was first put forward by Einstein. Einstein predicted this future astronomical observation technology in 19 12. Nowadays, astronomers from 1 1 country are using gravitational microlens technology to search for and look at the second "solar system".

New home?

Researchers generally believe that the existence of alien life generally conforms to the following laws: First, there must be terrestrial planets in the planetary system, the so-called "livable zone"; Secondly, the temperature in this area should not be too high or too low, and water should exist in liquid form; Third: solid planets are more suitable for survival than gas planets.

In April last year, scientists discovered the planet "Grice 876" 20 light years away from the Earth, and thought it was the "first planet suitable for human habitation" in outer space. However, after a series of experiments, researchers thought it was unlikely to have life because its structure was very different from that of the Earth. This new discovery shows an analogy of the solar system, or a "shrinking solar system", and scientists have new goals in analyzing the alien life environment.

Scott Gaudi, an assistant professor of astronomy at Ohio State University, said that theorists have been speculating whether gas planets in other "solar systems" also form and operate as seen in our solar system. Now the discovery of the second "solar system" proves that this hypothesis is true. People have reason to further speculate that there are still solid planets to be discovered in this new galaxy, and even a "small earth".

Dr Martin Domenech of the University of St Andrews said: "A series of recent discoveries show that some planetary systems are more and more similar to the solar system. We can even expect that one day we can find a planet similar to the earth, orbiting a new star, which will be our new home. "

According to British media reports this morning, scientists measured the tungsten isotope in the moon metal and found that the Earth and the moon may have appeared between 52 million and 654.38+52 million years after the formation of the solar system, but 62 million years is considered to be the most accurate.

Regarding the formation of the moon, the mainstream opinion in the scientific community is that the moon was originally a part of the earth. At that time, the earth was hit by an object the size of Mars, spewing out a lot of magma. Solidified and circled the earth, becoming the moon.

The article "The Origin and Evolution Stages of the Solar System" published in Scientific American (Chinese Edition) in 2000 10 first put forward the theory of the origin of the solar system. And successfully explained many unsolved mysteries of the solar system, such as the formation mechanism of asteroids and why Uranus is lying down. According to this theory and the current scientific understanding of the origin of the solar system, the stars in the solar system are formed by the same nebula. That is to say, all celestial bodies in the early solar system, including the sun, planets, satellites and fragments that failed to form big stars, are made of the same substance. In the long evolution process of more than 5 billion years after their formation, each star has undergone great changes in its own evolution stage because of its different volume, mass and spatial position in the solar system. We must also realize that the mainstream of this change is irreversible. In this paper, the evolution process of celestial bodies in the solar system will be discussed in combination with other unsolved mysteries in the solar system.

First, the origin and evolution of the moon

The moon is the closest natural celestial body to the earth and a satellite of the earth. It now runs in an orbit about 384,000 kilometers from the Earth. It is an approximately spherical star with a diameter of 3500 kilometers. It is also the only extraterrestrial star that has been visited by humans, and a large number of rock samples have been reserved for it. In a word, the moon is the most familiar big celestial body except the earth. Because there is no liquid or gas flowing on the surface of the moon, there are billions of years of changes on it. Comparing it with the earth can demonstrate the evolution of the moon, which is very important for understanding the earth and solar system where we live.

If the sun, the earth, the moon and other planets are all made of the same substance in the early stage of formation, then the moon in the early stage of formation should also be made of hydrogen and helium. According to this calculation, the volume of the moon at that time was larger than that of the earth now. The mass is about 0.8 of the mass of the earth now. It runs in orbit around the earth; Relative to the earth, the moon rotates synchronously. Because the mass of the earth and the moon is constantly changing in the evolution process, the distance between the moon and the earth is a variable in the future evolution years. About 5 billion years ago, nebulae condensed into the moon.

We know: whether it is igneous rocks on the earth, rocks on the moon, or meteorites that landed on the earth. They all went through the melting stage. Based on this, it can be inferred that the rock parts of the earth, the moon and other terrestrial stars have experienced overheating and melting periods. The physical mechanism of this hot melting period is the source of hot melting energy. There are different opinions in the scientific community. Nowadays, it is generally believed in astronomy that it was caused by a compact small rock asteroid hitting a star.

However, the astronomical community itself cannot justify this explanation. For example, there is a lot of water on the earth now, and the above explanation cannot solve the problem. Some people think that when a large number of asteroids hit the earth and the rocks on the earth are in a molten state, all the water on the earth evaporates in the air because it can't withstand the high temperature. After a long period of cooling, the water on the earth returned to the ground. Here's the problem: according to the current mass of the earth, it can't attract so much vaporized water. Others directly pointed out that there was no water in the terrestrial planets such as the earth and the moon when they went through the thermal melting period. After they went through the overheating period, a very big comet hit the earth and brought the present water to the earth.

Here is an interesting hypothetical phenomenon. In the process of discussing astronomical problems, especially when discussing various unsolved mysteries of the solar system, there are major problems that cannot be explained. Some people always fantasize that another big planet will hit the problematic star, so that the unexplained problems on the star can be solved. For example, a planet flew in and hit the planet in the asteroid belt, breaking it and forming the present asteroid belt. Another big planet hit Uranus, putting Uranus in its own orbit. Because the density difference between the earth and the moon is too big; Some people think that a big star crashed into the earth, and the material that hit the Pacific Ocean formed the moon in the sky. Plus the great comet that brought water to the earth. At present, the astronomical community basically believes that these four planets once existed.

As far as these four big stars are concerned, if they don't collide with other stars, according to their trajectories, they should be irregular planets (regular planets have the characteristics of * * * areal, isotropic and nearly circular) and very large comets. In the solar system, according to the principle of celestial mechanics and the probability of events, the probability of irregular planets and very large comets is almost zero. Because the solar system has never seen such a big planet, what's more, such an accurate planetary collision is an astronomical phenomenon that is impossible to happen.

What really happens on the moon is a process: the protostar of the moon piled up with a lot of materials begins to heat up, and the volume of the moon that heats up further becomes smaller. The accumulated energy (potential energy) further increases the temperature inside the moon. At this time, the moon is a liquid hydrogen helium sphere with a thick hydrogen layer and a small amount of other substances outside. After a long period of evolution, a small amount of other substances accumulated in the center of the moon, and the accumulated potential energy of these substances raised the temperature of rock substances in the center of the moon to 4000℃. Judging from the rocks obtained on the moon, they have not only experienced high temperature process, but also experienced high pressure process, because they all look relatively dense. If the high temperature and high pressure process described above is true, then the above process can also be reversed to confirm that the volume of the moon at the beginning of its formation was much larger than it is now.

When the heavy matter on the moon began to accumulate in the center of the moon, the hydrogen fusion of the sun began to explode. At this time, the intense radiation of the sun raises the temperature of hydrogen on the surface of the moon, and the movement speed of high-temperature hydrogen molecules reaches the cosmic speed of leaving the moon. Under the action of the solar wind, these hydrogen substances will constantly leave the orbit of the moon and the earth and run to distant places of the sun.

Just about 4.6 billion years ago, the hydrogen on the moon lost 70%. As the mass of the moon becomes smaller, the vaporization and separation speed of hydrogen and helium on the moon increases. This accelerated vaporization process takes away a lot of heat energy from the moon, which reduces the core surface temperature to below 1000℃. Rock becomes difficult to flow, but it will solidify. By the way, please note that the evolution of the above asteroids and the moon basically happened at the same time. Although the asteroid is much farther from the sun than the sun is from the moon, the planetesimals in the asteroid's orbit are much smaller than the moon. This evolution of the earth took place 3.8 billion years ago. All the physical evolution processes mentioned above can be completely simulated by computer.

About 4 billion years ago, due to the debris of rocky asteroids, many asteroids were out of their original orbits and scattered all over the solar system, forming the peak period of asteroids hitting big planets. The moon was also destroyed by asteroids during this period.

After 3.9 billion years, most of the water and volatile substances on the moon have basically flown away, and the pressure on the rocky moon has gradually decreased. Because the moon rotates synchronously with the earth (facing the earth unilaterally), under the action of the earth's gravity, perhaps a meteorite impact caused the plagioclase layer on the moon's surface to crack, and the ejected basaltic magma formed a large area of the moon sea. If we can carefully observe the current contours of the moon and the ocean, we can reach the same conclusion.

In the long years that followed, the moon slowly cooled down. When the condensed rock reaches a sufficient thickness, asteroids that fall on the moon will hit star-shaped cracks and craters on the moon. If an iron asteroid hits the moon, it will become a lump if it stays in the moon rock. The moon continues to cool, and when the moon rocks at a distance of 1000 km start to cool, the center of the moon begins to shrink. Under the strong support of lunar crust rocks, the center of the moon contracts, forming intermittent empty interlayer between them. When there is a moon earthquake, the moon will shake like a drum for a long time.

The reason why the density of the earth and the moon is different is: 1. The rocks on the earth have experienced higher temperature and pressure, so the earth has better geological evolution. The earth is a planet and the moon is an ordinary satellite. Their motion states are different. As a result, the density of stars formed by two points will be very different.

The evolution of the moon has been until today, and in the second half of the evolution process, the physical changes of the moon are not too great. It is now quietly rotating around the earth, and sometimes there are some imperceptible activities.

Of course, the above is only a very simple changing outline of the evolution of the moon. Some details of the evolution process, especially the subtle details of the chemical evolution of the moon, should be discussed by a special discipline-the evolutionary chemistry of planetary bodies, so I won't go into details here.

Let's compare the evolution of the earth: in 3.6 billion years, the earth lost a lot of materials. When the temperature of the outer crust of rocks dropped to a certain temperature, the plagioclase layer began to condense. In the following time, the hydrogen and helium substances on the earth were further lost, reducing the pressure on the rock core of the earth; By about 2.6 billion years, the crust of the earth's plagioclase broke, and the exposed basalt layer became the seabed. It is this evolution process that provides the source power for the theory of plate motion of the earth. According to this theory of evolution, many other natural phenomena on the earth can also be explained.

Second, the principle of the origin of the solar system is questioned.

People will question the hypothesis of the origin of the solar system: the longest life span of human beings is only over one hundred years, and the history of human civilization is only five thousand years. The evolution of the solar system began 5 billion years ago, so how can we determine how the stars in the solar system evolved?

When dealing with human history, in order to confirm the age of events, we use the mutual confirmation of historical materials to determine. For the recent evolution history of the earth, we will investigate the stratigraphic data of geological age to determine it. For the evolution history of the universe such as stars, galaxies and even the sun, human beings should use known physical theories and observable facts to demonstrate; This kind of demonstration can be the exploration of knowledge and the confirmation of quantitative calculation results. It is better to simulate the whole evolution process by computer.

When we use these physical and chemical knowledge and modern science and technology to expand our knowledge of the world, we will never forget those pioneers who struggled in foggy nights and scientists who made unremitting efforts for scientific progress. It is their hard work that makes us humans begin to have a sense of our world.

In the discussion of astronomy, many astronomers think that the understanding of stars is much clearer than that of the solar system. Because there are too many mysteries and uncertainties in the evolution of the solar system and its planets. After stars condense from nebulae into stars, stars with different masses from small to large can not only quantitatively calculate their evolution patterns, but also simulate their evolution process with computers. But the sun in the center of the solar system is an ordinary star, and the above problems stem from this stage before the nebula forms the sun and planetary system. Many people put forward a mathematical evolution model, and used computers to simulate the process of rotating nebulae forming the solar system (1978 Bodenheimer and Chanute). However, all they got was a circle of nebulae. There is no initial system of the solar system.

In fact, the mathematical model of computer simulation of solar system evolution is inconsistent with the evolution process. It is because when the solar nebula shrinks from angular momentum to a certain density, the evolution of the solar nebula enters the stage of planetesimal evolution, that is, this stage of evolution has not been paid attention to. The evolution stage of planetesimals is a very important stage in the evolution of the solar system. If the mathematical model of solar system evolution does not consider the evolution stage of planetesimals, it is impossible to get the result that stars and planets surround galaxies.

The scientific community studies such important scientific issues as the evolution of the solar system. They all put forward the hypothesis of evolution, and then quantify it according to the known laws of physical chemistry. Under various boundary conditions (observed and observed facts), the whole demonstration (computer calculation or reproduction) and the answer are obtained. We live in the solar system, and many things we see are the result of the evolution of the solar system (boundary conditions). It is of course very difficult to put forward the hypothesis of solar system evolution when so many boundary conditions are completely satisfied. But in the end, the results obtained by using these many evolutionary boundary conditions should also be the only conclusion.

The theory summarizing the origin principle of the solar system is as follows:

1. According to the origin tendency of the solar system, the initial celestial bodies in the solar system were formed by a nebula, and the abundance of substances contained in the celestial bodies in the solar system should be basically the same.

2. The mass of the star, the contents of various substances, the temperature determined by the position of the solar system, the parameters of the star's motion state and the evolution time are all quantifiable physical quantities, which determine the physical and chemical state of the star.

3. The physical and chemical evolution of the state of stars in the solar system is continuous. The main changes of stars are determined by their changing factors.

4. The mainstream process of solar system evolution is irreversible.

The above theories are the evolutionary norms of the origin and evolution of the solar system.

Third, look at the solar system according to its origin principle.

To sum up, every celestial body in the solar system has its own evolution story. For today's astronomy, every celestial body has many mysteries. The origin theory of the solar system can basically explain many unsolved mysteries. For example, how can there be carbon asteroids in the asteroid belt? The reason is that the original mass of many asteroids is very small. When they lose hydrogen and helium, water begins to vaporize. Because of the small mass of asteroids, water vapor escapes directly into space, and finally only carbon and other nonvolatile rocks remain in asteroids. The gravity of massive asteroids makes it difficult for water vapor to escape, and the solar wind splits it into hydrogen and oxygen. Hydrogen leaves the asteroid first, oxygen combines with carbon to produce carbon dioxide, and finally leaves the asteroid. So asteroids generated by massive protoasteroids are stars made of stone and iron.

Due to the limited space here, it is impossible to discuss the evolution of all stars. Let's use the principle of the origin of the solar system to re-understand our current solar system.

Inner solar system: This system includes four planets: Mercury, Venus, Earth and Mars, and other asteroids with satellites and asteroid belts. They are all stars formed with the sun in the early solar system. Because it is close to the sun, it has lost hydrogen and helium substances after long-term evolution, becoming a terrestrial planet with smaller stars, and the orbital distances between the major planets are also relatively close. They only operate within three astronomical units.

When small stars containing light substances such as hydrogen and helium in the outer solar system are influenced by other big stars and change their orbits into the inner solar system, they will all become long-tailed comets.

The asteroid belt in the inner solar system should be called the first asteroid belt.

Near-orbit planetary belt: This planetary belt includes many kinds of stars. Among them, the big planets are Jupiter, Saturn, Uranus and Neptune. They were formed after the nuclear fusion explosion of the sun. They are large in size and mass. Because of their great gravity, they are relatively far from the sun; Their hydrogen and helium substances can hardly escape. The distances between planetary orbits are similar, but the densities are not much different.

Planets in this planetary belt have rings and many satellites. The mass of ring materials and satellites is not large, and most of their hydrogen and helium materials escape; So they are all made of stones and ice. Compared with big planets, they are relatively small.

There should be asteroids and accidental comets in this system. Being far away from the sun, the comet's tail is very thin and difficult to see.

The stars in this system move within 35 astronomical units.

Second asteroid belt: The width of this asteroid belt is 20,000 astronomical units. There are hundreds of millions of planets in this asteroid belt. Because of the large bandwidth of this star, the influence of solar radiation on the stars in this area is different, so this area can be divided into two.

Among them, there is a partition within 5000 astronomical units from the sun, and there are two kinds of planets in this area.

The first is a relatively large asteroid. The concentrated energy of this star and the radiant energy of the sun make the internal and external temperatures of the planetary body exceed the condensation temperatures of hydrogen and helium. But its mass is not enough to hold gaseous hydrogen and helium, so the density of stars without light matter is higher. More than 60 planets visible in Pluto and the Kuiper Belt (and Triton captured by Neptune) belong to this kind of asteroid.

The second is a planet with a small mass. Because of its small mass, the interior of the star has not changed, and it still maintains the original mixed state of hydrogen, helium and other substances. Some light substances such as hydrogen and helium are driven away from the surface by the sun's radiation, and the remaining heavy substances cover the surface of the star. It is appropriate to call it a "dirty snowball". A few of these planets changed their orbits under the pressure of big planets, and some of them entered the inner solar system. When they are close to the sun, there will be spectacular eruptions. We call such stars "comets" (short-period comets).

In the subarea of 5000-20000 astronomical units from the sun, the material state of asteroids is basically the same as that of Taiyang Yuan Nebula.

Far-orbiting planetary belt: during the formation of the solar system, a large number of substances were ejected from the sun and the inner solar system. Some of them are captured by planetesimals in the near-orbit planetary belt, forming giant planets. In addition, a large part of the material is not captured. In addition, the hydrogen and helium emitted by the smaller stars in the near-orbit planetary belt and the hydrogen and helium emitted by the planets in the second asteroid belt gradually spread out of the sun.

According to the theory of the origin of the solar system, there are three conditions for the formation of large planets: First, there must be enough matter in the gravitational range of stars. Second, the temperature. The emission substances mentioned above are gaseous substances such as hydrogen and helium, and their agglutination temperatures are all below 10K. The third is time, that is, these substances have to run for a certain number of planetary years before they can accumulate into big stars.

According to the above conditions, we can roughly calculate the basic parameters of the major planets in the far-orbit planetary belt: within the range of about 22,000 ~ 27,000 astronomical units from the sun, at least three major planets are in orbit, and their orbital spacing is about 100 astronomical unit. It takes 265,438+00 to 2.6 million years to orbit the sun once.

In the first orbit, there are two or three big planets with the same mass as Saturn. Because the material accumulation time in this orbit is not long enough, the solar system is only tens of millions of years in the early stage and a billion years in the later stage, and the material here has not had time to aggregate into a big planet. The density of these stars is 0.7g/cm3. Planets are unevenly distributed in orbit.

The giant planet in the second orbit is a giant planet with a mass more than twice that of Jupiter (the largest planet in the solar system), with a diameter of about10.9 million kilometers and a density of less than 0.7g/cm3.

The third orbit is 4 to 6 planets smaller than Saturn, and their density is 0.6g/cm3. It will take billions of years to get them together.

Standing on the largest planet, seeing the sun is similar to seeing Venus on the earth. With the help of light from other stars, the brightness on the surface of this big planet is much darker than that on the back of the moon. Its plane viewing angle is only 0.07 arc seconds (Pluto is 0. 1 1 arc seconds). You can't see it with ordinary optical telescopes. It can be seen that many people will regard it as a star, because this big planet only moves for 0.5 arc seconds every year. It will take 300 years to launch a probe to investigate it. Its rotation period is 20~30 hours.

The big planets here all have rings made of fine particles, and they also have many satellites. You can also see satellites here. There is a way to calculate the orientation of the planet with the largest mass, and the appearance probability and orbital parameters of many long-period comets visiting the inner solar system can provide the running information of these planets.

The third asteroid belt: the width of this asteroid belt is above 654.38+ million astronomical units. There are asteroids larger than 1 000 km in the 1 0,000 astronomical unit starting from the distant planetary belt, and the rest materials are rarely distributed. There are hundreds of billions of celestial bodies running in this planetary belt. It takes hundreds of millions of years for the stars at the edge of the planetary belt to orbit the sun. The influence of the sun on them (gravity and radiation) is negligible.

For the second asteroid belt and the third asteroid belt, most astronomers now think that the material left over from the formation of the solar system is a group of comets, called Oort Cloud. Oort cloud is the primitive material of the solar system symmetrically distributed on both sides of the sun.

Re-understanding the solar system, it is possible that we can't know the total number of planets in the solar system, and we can't know the real situation in the distance of the solar system. We may know very little about the solar system.

Four. Concluding remarks

Throughout the history of the earth, we humans may be in a childhood when we can really do something, but we don't know what we are doing. In this era, human beings are most likely to harm themselves and their living environment.

Therefore, now we must realize that the origin of the solar system may take a long time to solve. But we are already in an era when human technology can almost change our living environment. If we don't have a deep understanding of our living environment, we may make some irreparable mistakes and lose the only earth we can live on. So the origin of the solar system is a big problem that we should know as soon as possible.

References:

Ingels Planets, Stars and Galaxies Science Press 1979.

Schmidt Four Lectures on the Origin of the Earth Science Press 1954

Evolution of Celestial Bodies Dai Wensai Hunan Education Press 1999.

Hu Zhongwei's Introduction to Planetary Science Nanjing University Press 1998

The Mystery of the Moon in Rocky Mountain Southern Publishing House 2000.

Kippenghahn1000 billion suns Hunan Science and Technology Press 1999

Liu Xuefu's New Exploration of the Solar System seismological press 1999

Li Jing Space Exploration Science and Technology Literature Publishing House 1999

The Origin-Evolution Stage of Liu Yuansheng Solar System Science (USA) Chinese Edition 2000 10