A story about the moon

classification: education/science > > Science and technology

Description of the problem:

Kneeling for the story about human exploration of the moon

Analysis:

Exploring the mystery of the moon

The moon is the closest celestial body to the earth, with a distance of 384, kilometers. Astronomers have already observed the moon in detail with telescopes, and they are almost familiar with its topography. There are mountains and plains on the moon, and there are numerous pits and ravines, but there is no water and air. The temperature difference between day and night is hanging, and it is dead and desolate. Although the giant telescope can distinguish the target about 5 meters on the moon, it is still not as clear as the field trip. Therefore, the moon is still the first extraterrestrial object visited by human beings.

the United States first launched a lunar probe on August 18th, 1958, but it died halfway because the first stage rocket exploded. Subsequently, three Pioneer probes were launched one after another, all of which failed. On January 2, 1959, the former Soviet Union launched the Lunar 1 probe, which flew smoothly on the way. On January 4, it passed 75 kilometers from the surface of the moon, but unfortunately it failed to hit the moon. This detector weighs 361.3 kilograms and is equipped with the most advanced communication and detection equipment at that time. It became the first artificial planet to fly deep into space nine months later. On March 3, two months after the launch of Lunar 1, Pioneer 4, launched by the United States, flew over 59, kilometers from the lunar surface and did not hit the moon.

lunar probe

from 1958 to 1976, the former Soviet union launched 24 lunar probes, 18 of which completed the mission of exploring the moon. Lunar 2, launched on September 12, 1959, flew to the moon two days later and landed hard in Chenghai on the surface of the moon, becoming the first messenger to reach the moon and realizing the flight from the earth to another celestial body for the first time. The radio communication device in its scientific instrument cabin stopped working after hitting the moon. On October 4th of the same year, Lunar 3 flew to the moon, circled the back of the moon three days later, and took the first picture of the back of the moon, which made people see the full face of the moon for the first time. The first probe in the world to make a soft landing on the moon was Lunar 9 launched on January 31, 1966. After a 79-hour long flight, it landed near the stormy ocean of the moon and took pictures of the moon with a camera. This probe weighs 1,583 kilograms. When it reaches 75 kilometers from the lunar surface, the landing module weighing 1 kilograms is separated from the probe body, and it landed slowly by the automatic inflatable balloon installed outside. Lunar 16, launched on September 12, 197, made a soft landing in the rich sea on the lunar surface on September 2. For the first time, 12 grams of lunar rock samples were collected with a drill bit, put into a sealed container in the recovery cabin, and brought back to Earth on the 24th. On November 1, 197, Lunar 17 carried the world's first automatic lunar rover into the sky. After landing in the rainy sea on the lunar surface on the 17th, the lunar rover No.1 went down to the lunar surface for 1 and a half months of scientific investigation. The lunar rover weighs 756 kilograms, is 2.2 meters long and 1.6 meters wide, and is equipped with a TV camera and a nuclear energy device. It traveled 1,54 meters on the moon, surveyed 8, square meters of lunar area, and took 2 panoramic photos of the moon and more than 2, photos of Zhang Yue. It didn't stop working until the nuclear energy was exhausted on October 4, 1971. On January 8, 1973, Lunar No.21 was launched, and Lunar Rover No.2 was sent to the surface of the moon to make more achievements. The last Lunar 24 probe was launched on August 9, 1976. On August 18, it made a soft landing in the dangerous sea on the lunar surface, drilled and brought back 17 grams of moon rock samples. At this point, the unmanned exploration of the moon by the former Soviet Union was completed, and people's understanding of the moon was richer and more complete.

rover, surveyor probe

After the former Soviet Union, the United States launched nine rover and seven surveyor lunar probes. The rover detector looks like a big dragonfly, 3 meters long, and the solar panels on its wings are spread out 4.75 meters. The detection instrument is installed at the front, and the TV camera is placed at the rear. The surveyor's probe has three feet, weighing 1 ton in total, and is equipped with the most advanced detection equipment at that time. The first five rover probes failed, and it was not until the ranger 6 launched on January 3, 1964 that it landed in the Jinghai area on the lunar surface. However, due to the failure of the TV camera, the photos were not taken back. On July 28th of the same year, Wanderer 7 was successfully launched and landed in the sea of clouds on the moon, taking a close-up photo of 438 Zhang Yue. Subsequently, Wanderer 8, launched on February 17th, 1965, and Wanderer 9, launched on March 24th, both successfully landed on the moon, and took 7137 and 5814 close-range photos of Zhang Yue respectively. On May 3th, 1966, the new probe Surveyor-1 was launched. After a 64-hour flight, it made a soft landing in the stormy ocean on the lunar surface and sent back 11,15 Zhang Yue photos to the ground. Of the seven Surveyor probes launched on January 1, 1968, two failed and five succeeded. Later, the United States launched five lunar orbiters to provide detection data for Apollo manned landing on the moon. After this series of unmanned exploration, the true face of the moon was revealed.

Since July 16th, 1969, when the American Apollo 11 spacecraft landed on the moon for the first time. According to the results of many field explorations of the moon and the analysis of rocks and soil brought back from the moon, human beings have learned more about the face of the moon. Scientists believe that the rocks on the moon are older than those on the earth. The moon and the earth are almost composed of the same chemical elements, but the composition is different. For example, moon rocks contain more calcium and aluminum than rocks on earth. The moon has no magnetic field, and its shell is relatively stable, with little change in the past 3 billion years. Although astronomers have long believed that the moon is petite, its gravity is weak (1/6 of that of the earth), and it does not have the ability to bind the atmosphere at all. Under the high temperature on the sunny side, any gas molecule will easily escape from the speed. However, the measured data on the moon show that the surface of the moon is not a country without any atmosphere, but the atmosphere is too thin, and the atmospheric pressure on the surface is only 2X1 bar, and the atmospheric composition is complex and changeable at any time. Usually, the atmospheric composition at night is mainly composed of 4% argon, 4% neon and 2% helium, and a very small amount of methane and ammonia will be added at sunrise. In some areas, a very small amount of hydrogen and ammonia will be found in the atmosphere. American scientists have claimed that there is ice on the moon, which may provide drinking water for people who explore the mysteries of the moon, and also decompose ice into hydrogen and oxygen, thus providing fuel for rockets.

from the field exploration, it is found that there are more than 3, craters on the moon, which are dotted and surrounded by each other. The largest crater, with a diameter of nearly 3 kilometers and an elevation of more than 6, meters, is very spectacular. Unfortunately, because there is no water source on the moon, these mountains are bare, barren and desolate. Obviously, in order to make such a desert moon world a paradise suitable for living things, and finally become a vibrant, all things competing, beautiful birds and flowers on earth, it is imperative to solve the water supply problem on the moon. Over the years, scientists have put forward many ideas. There is a solution: mining iron oxide which is extremely rich in storage on the moon, smelting it with a solar melting furnace, releasing a large amount of oxygen, and combining it with liquid hydrogen collected by transport spacecraft from space to generate water for the development of the moon. This scheme of synthesizing water from local materials in the moon and space is feasible in principle, but it is by no means easy to implement this huge project, which involves a series of problems such as energy, mining, transportation and life.

The most attractive thing for human beings is that the lunar soil contains a large amount of gaseous "helium -3", which is a nuclear material with much lower radioactivity than the deuterium raw material used in nuclear power plants on earth at present. Helium -3 was originally abundant in the high-energy particle stream (solar wind) ejected by the sun. On the moon with almost no atmosphere, the "solar wind" directly descended. Over time, there are about 1 million tons of this material in the sand and rocks on the moon. If it can be exploited in large quantities, it will not only provide the energy needed for the development of the moon, but also provide inexhaustible nuclear energy raw materials for the nuclear fusion of the earth in the 21st century.

The duration of day and night on the moon is as long as half a month, with the highest temperature of 127℃ during the day and the lowest temperature of-183℃ at night. Such a hot and cold climate with drastic temperature difference is another important reason why there are no people and life on the moon. Russian scientists have made long-term research on how to use the soil and rocks on the moon to make building materials such as cement, and then use these materials to build a living base that can adjust the room temperature and make it suitable for human habitation. One scheme is that they think that the moon is probably a hollow sphere by analyzing some measured data of the moon. Based on this understanding, one day, we can make a tunnel on the surface of the moon and enter the "underground moon palace" deep in the lunar crust, where we can build an "underground city" suitable for human habitation. In this way, tourists who fly to the moon by spaceship can find hotels for the night in this "underground city". Scientists and technicians can use this underground city as a base to engage in activities such as lunar resource exploration, space product production and astronomical observation. Before the permanent base of the "underground moon palace" was built, scientists suggested that some prefabricated plastic mold components could be made on the earth to form a giant cylinder that automatically rises vertically. After being assembled in advance, it is sent to the surface of the moon by a space transport ship. As soon as the cylinder lands on the surface of the moon, it will automatically split into two halves and open, and automatically form a multi-storey building as a temporary residence for volunteers who first landed on the moon.

(Sina Technology)

Second, the birth of the moon

The mystery of the birth of the moon

How was the moon first formed? This is a controversial issue in the scientific community. At present, there are roughly three theories.

"captive" theory: Some scientists believe that the moon was originally a meteor. When it was flying aimlessly in space, it accidentally entered the range of gravity and was bound by the gravity of the earth, so it was accidentally brought into the earth's orbit. However, in recent years, many people have cited celestial mechanics to oppose this statement.

"Split" theory: Scientists who hold this view believe that the moon is split from the earth surrounded by a fiery rotating cloud, so the moon is the "child" of the earth. However, the data brought back from the Apollo spacecraft several times show that the composition of the moon and the earth is quite different.

"collision" theory: This theory holds that about 4.5 billion years ago, a planet larger than Mars suddenly hit the early earth at a speed of 4, kilometers per hour, so hard that the iron core of this planet hit the center of our earth all the time. The result of the collision was a huge explosion, accompanied by a high temperature above 6 degrees Celsius. The earth was deformed under the impact of the explosion. Most of this huge celestial body, which committed suicide, merged with the earth, and only a part of it was violently ejected into outer space as hot steam with other debris. Later, the steam cooled down and solidified into dust, which was mixed with other debris to form a nucleus, which later condensed into a group, and our neighbor, the gray moon, was born.

Scientists are using new supercomputers to simulate this strange collision in space in order to verify this theory.

a new theory on the origin of the moon

where did the moon come from? This is a question that people are constantly exploring. In recent years, with the rapid development of planetary evolution theory and the wide application of modern computer technology, a new theory of the origin of the moon has emerged, called the new capture theory.

Looking at the origin of the moon from the perspective of planetary evolution

In recent years, based on the modern planetary evolution theory, scientists have calculated the forces acting on the sun, the earth and the moon in the early days of the formation of the solar system by computer, and have come up with a new theory of the origin of the moon. Scientists believe that the moon was captured by the earth in the early stage of its formation within the gravity range of the earth; And this phenomenon was very common at that time. This new theory, the so-called new capture theory.

the new capture theory is different from the old capture theory. The old saying is that the origin of the moon is only considered from the gravity of the earth; The new theory studies the origin of the moon from the whole process of planets of the solar system formation. The new theory holds that the nine planets and some satellites in the solar system, including the moon, all originated from the primitive solar system nebula. The primitive solar system nebula is a thin disk nebula formed around the primitive sun 4.6 billion years ago. The nebula contains solid particles. A large number of particles gradually gather on the equatorial plane of the nebula, forming a thin layer of solid particles. With the increase of particle density, their own gravity is getting stronger and stronger, and to a certain extent, their stability is destroyed and crushed into many small celestial bodies with a radius of about 5 kilometers, that is, asteroids. The entire solar system was originally made up of about one trillion asteroids. Countless asteroids revolve around the sun in nebula gas, collide with each other, and gradually condense and grow, forming planets of different sizes. Our earth is like this. It took about 1 million years to grow to such a big size.

planets grow in nebula gas. When the earth was young, it was covered with dense nebula gas, which was called primitive atmosphere. Because of the intense solar activity at that time, the strong solar wind gradually dispersed the primitive atmosphere, and then the primitive atmosphere surrounding the earth gradually thinned and drifted away.

the moon also originated from the primitive solar system nebula, which is roughly the same as the evolution process of the earth. The moon flew close to the earth's gravitational circle when the earth just reached adulthood and the primitive atmosphere began to escape, thus becoming a prisoner of the earth.

Four forces that capture the moon

After the moon enters the earth's gravitational circle, it is subjected to many forces before staying in the orbit of the satellite. There are four main forces to capture the moon, namely, the gravity of the earth, the gravity of the sun, the tidal force and the resistance of the primitive atmosphere.

generally speaking, the gravity is the biggest force on small celestial bodies, including the moon, flying into the earth's gravity circle. However, only the gravity of the earth, the orbit of the captured small celestial body is not elliptical. After the gravity of the earth and the gravity of the sun, the orbit of small celestial bodies has changed. Under the gravity of the earth and the sun, the orbit of small celestial bodies entering the earth's gravity circle is not completely elliptical, and after flying for several weeks, they will inevitably escape from the gravity circle and cannot stay in the satellite orbit.

however, the moon has not escaped from the earth's gravitational circle, which is due to the resistance of the primitive atmosphere. The primitive atmospheric resistance in the earth's gravitational circle has a sharp braking effect on the flying moon, which makes the moon lose part of its energy, and the orbital radius becomes smaller, so it can't run away.

So, the radius of the moon's orbit is getting smaller and smaller due to atmospheric resistance. Isn't it necessary to fall to the earth and collide with it sooner or later? Don't worry, when the moon flew into the earth's gravitational circle, the primitive atmosphere began to drift away gradually, and the atmospheric resistance on the moon became smaller and smaller. After the primitive atmosphere disappeared, the resistance on the moon also disappeared, so the orbital radius did not decrease and it did not collide with the earth.