In a general sense, any moon is actually just a planet in a satellite orbit. The moon we usually call usually refers to the only natural satellite of the earth. It is the only natural satellite of the solar system. The fifth largest celestial body in the sky and the second brightest object in the Earth's sky. As early as 50 years ago, humans achieved the first landing on the moon. We saw the large and small craters on the surface of the planet, and understood why we can only see the same side of the moon, and the fact that the moon's outer shell has shrunk. . However, as these mysteries are revealed, many new doubts arise, such as: how do scientists obtain important information about interstellar meteorites through observations of the moon, and whether the "far side" of the moon is How will the shrunken moon in darkness undergo evolution in the future? The moon's craters can reveal the source of the impactor

According to scientists' current understanding of the moon, the planet is about 4.3 billion years old due to the impact of many asteroids. Its surface is covered with craters of various sizes, and some of the cracks can even extend to a depth of about 20 kilometers, so they do not just leave traces of the passage of other objects. After scientists have explored the moon for a long time, almost all of these craters on its surface have been fully documented, but little is known about the upper regions of the moon's crust. According to data collected by NASA's GRAIL (Gravity Recovery and Interior Laboratory), the actual density of the lunar crust is much lower than scientists previously expected. This is closely related to the large surface fractures caused by ancient impacts on the moon. , because when such an event occurs, it will cause the porosity to increase and the density to decrease.

We can express this process through a more vivid set of data. For example, an object with a diameter of one kilometer may cause cracks on the moon to a depth of about 20 kilometers, while an object with a diameter of 10 kilometers will impact the moon. After that, the depth of the crack may not differ much, but it will extend laterally to about 300 kilometers from the impact crater. Over time, these cracks grew and connected together, creating the fragmented lunar crust we see today. The reason why we can see them so clearly is because the moon itself has no atmosphere. The telescope is not pointed into space, but pointed directly at the surface of the moon, so we can also see the time when these impacts occurred.

When an impactor streaks across the lunar surface, always accompanied by an explosion and subsequent crater formation, meteoroid shadows and reflected sunlight will be searched for. The spectra produced by explosive impacts help to understand the composition of these meteoroids, the elemental richness of their original systems, and the possible location of habitable planets. By observing the speed of the object moving relative to the shadow before impact, scientists calculated The three-dimensional velocity is derived to understand whether the meteoroid comes from the distant outer solar system. Scientists are even able to learn about the meteoroid's mass, three-dimensional velocity, density, and even the radiation efficiency of the impact from these measurements, deepening our understanding of the origin and composition of interstellar objects, as well as insights into other planetary systems and our own. There is a deeper understanding of similarities and differences. The entire far side of the moon is not equal to its dark side

When we on the earth look at the moon, it seems that it will always look the same, but it will appear different in size due to time and weather. This state is actually due to the so-called tidal locking. The moon always has the same side facing our earth. The distance between the two planets is so close that they exert important gravitational forces on each other. Their rotation speed is also slowed down by tidal gravity, and the moon's rotation and orbital period are synchronously locked in a shorter period of time. At present, the time it takes for the moon to orbit around its axis of rotation is about 28 days, and the time it takes for it to orbit the earth is about 28 days. Therefore, the moon we see will be the same side, and the earth in the lunar sky is also about 28 days. Always at rest.

Scientists have conducted more research on the near side of the moon, and we can directly observe it, while the far side of the moon is relatively more mysterious, but if it is described as The dark side of the moon is not an accurate representation, because the world of the moon also has day and night.

On January 2, 2019, the Yutu 2 probe began its exploration of the far side of the moon shortly after touching down. Researchers were able to measure weak signals from the universe there, and could observe low-frequency signals from the sun or other celestial bodies. Radio, these are messages that we cannot detect on Earth. Scientists are exploring closer and closer to the moon's polar craters. The sun never seems to shine on the floor of these craters. There is a dark part of the moon, but it is not the entire far side of the moon. How will the shrinking moon end?

Scientists observed the vibrations of the moon and found that the cliff-like cracks on its surface were dragged, causing the outer layer of the moon to shrink, which means that our moon has shrunk. In the process, the researchers even re-examined the seismic data collected during the Apollo lunar landing missions from 1969 to 1977, and mapped the seismic data to the steep slopes or thrust faults on the lunar surface. These underlying extensions miles and dozens of feet high. Judging from the results of data analysis, about 25% of the moon may have been created due to the energy released by these faults, rather than from activities deep in the moon or asteroid impacts. In the LRO photos, there is a lot of evidence that the shrinkage of the moon is still taking place on the surface. The brighter spots exposed due to interference suggest that such activity has occurred recently and that its faults are still active. This may be due to the fact that the moon The contraction state continues.

Scientists can make greater progress in understanding the lunar geology through a larger network of modern seismometers to enhance our knowledge of the moon itself, but we are also concerned about how it will Finish. As we all know, the moon's orbit is currently moving away from the earth at a rate of 3.8 centimeters per year. If this rate of decline has been maintained since the formation of the moon, then we must stretch the time back to 13 billion years ago because of the earth's continental tectonic history. Can be related to the distance to the moon. The planet's rotation rate is slowed by the loss of tidal energy, causing the moon to move away. Tides are mainly controlled by the size and shape of the Earth's ocean basins. The geometry of the oceans changes as the Earth's tectonic plates move. The resulting tidal changes had a major impact on the mechanics of the moon. In short, we can derive position information related to the Earth and the Moon at a specific point in time through changes in the Earth's tectonic plates.

To get the answer to this question, we can try to find Milankovitch cycles in the chemical and physical changes of ancient sediments. These cycles are different from cycles in the general sense. They are all because Climate cycles are caused by changes in the direction and shape of the Earth's orbit, as well as changes in the direction of regional axes. For example, there were ice ages that existed on the Earth for millions of years. Scientists now aim to obtain a continuous record of the moon's decline over the past few billion years by repeatedly counting sediment data from hundreds of locations over different time periods. They can not only help humans better understand the tidal changes of the ancient moon, but also provide important hints on the evolution of the moon.