At 14:07 on June 25, 2024, China's Chang'e-6 successfully returned to Earth after a 53-day mission and brought back an impressive 1,935.3 grams of lunar soil, a feat that is not only another major breakthrough in China's space industry, but also has attracted widespread attention from the global scientific community. So, what is so special about the lunar soil brought back by Chang'e-6? Why did this mission attract the attention of the world? In this issue, we will talk about this topic.
In the history of human lunar soil collection, a total of 10 sampling missions were carried out, and a total of 383.77 kg of lunar soil samples were collected. These missions included six missions by the U.S. Apollo, three missions by the Soviet Union Luna and one mission by China's Chang'e-5. However, the sampling sites of these 10 missions were all located on the front side of the moon, and the first nine sampling sites were concentrated in the low latitudes of the front. The only exception is the sampling site for China's Chang'e-5, which is located in the mid-latitudes on the far side of the moon. In December 2020, Chang'e-5 successfully brought back 1,731 grams of lunar soil samples from the moon, and in the past three years, Chinese scientists have systematically studied these samples and achieved a large number of scientific results, covering a wide range of fields such as geology, geochemistry, space differentiation, impact, impact stripping, and lunar soil applications.
Li Chunlai of the Institute of Geology and Geophysics of the Chinese Academy of Sciences pointed out that one of the biggest discoveries of Chang'e-5 was that the basalt samples it collected were formed by a volcanic eruption about 2 billion years ago. This discovery, unlike the results of the sample studies obtained by the Apollo mission, suggests that the volcanic activity of the Moon has been extended by almost 1 billion years. These samples are a new class of basalts, formed from a completely new mechanism of magmatic activity, filling a gap in the study of lunar samples from the United States and the former Soviet Union. Bian Zhigang, deputy director of the China National Space Administration, said that from the samples brought back by Chang'e-5, Chinese scientists had discovered a sixth new mineral on the moon and named it "Chang'e stone". This discovery is further evidence that the Moon was still in magmatic activity 1.96 billion years ago, which greatly extends our understanding of the geological life of the Moon by about 1 billion years. Since previous samples have come from the front side of the moon, we can only recognize a part of the moon. Chang'e-6 is the first time to collect samples from the far side of the moon, which is expected to provide an opportunity to fully understand the history of the moon.
The far side of the Moon is a mysterious hemisphere that is forever facing away from the Earth. Since the rotation period of the Moon is the same as that of the Earth, this synchronous rotation results in us being able to see only one side of the Moon from the Earth, and never directly observe the other side of the Moon. The terrain on the far side of the Moon is more rugged than on the far side of the Moon, filled with dense impact craters. Most of these impact craters were formed billions of years ago and bear witness to the long and intense geological history of the lunar surface. Among the many impact craters, the Antarctica-Aiken Basin is particularly striking. This basin is one of the largest, deepest, and oldest known craters in the solar system. The Antarctic-Aiken Basin is nearly 2,500 kilometers in diameter and about 12 kilometers at its deepest point, which means that the impact force at that time was unimaginable. Scientists speculate that the massive crater was formed about 4.3 billion years ago, meaning that the moon experienced this devastating impact less than 1 billion years after its formation.
Such a violent impact not only changed the moon's topography, but also had a profound impact on its internal structure. The Moon is made up of the core, mantle, and crust. This major impact in the South Pole-Aiken Basin may reach the lunar mantle and even bring about the ejection of lunar nuclear material. At that time, the Moon was very active, and it is likely that mantle material and lunar nuclear material were washed out of the surface and scattered around the basin as a result of the impact. Since these substances have evolved over a long period of time, studying them can provide important clues about the formation and evolution of the Moon and the solar system as a whole. The goal of the Chang'e-6 mission is to travel to the Apollo Basin in the Antarctica-Aiken Basin to collect lunar soil samples. The Apollo Basin, located within the Antarctica-Aiken Basin, is a relatively flat area where a large amount of valuable geological records are preserved.
Lunar soil is a valuable material for studying the geological history of the Moon and the surface environment of the Moon, which not only helps us unravel the mystery of the formation and evolution of the Moon, but also provides important clues for us to understand the early Earth. The Earth's active geological activity, continuous plate movements and magmatic activity are constantly reshaping the earth's surface, resulting in very scarce outcrops of ancient rocks. This leaves us with very limited knowledge of the early Earth. The Moon, on the other hand, has long ceased its geological activity and retains a large rock record that is more than 3 billion years old. These ancient lunar rocks and soils provide us with a natural "time capsule". By studying lunar soil, we can not only trace the formation and evolution of the Moon, but also gain important clues about the early Earth. In addition, due to the long-term exposure of the far side of the Moon to the direct irradiation of the solar wind and cosmic rays, the lunar soil preserves a rich history of solar wind composition and cosmic rays.
The solar wind is mainly composed of hydrogen and helium, but also contains small amounts of heavy elements. By analyzing these components, scientists can understand the evolution of the sun and the effects of cosmic rays on the moon's surface. These studies will not only help reveal the history of the Moon, but also provide a reference for understanding the evolution of other celestial bodies in the solar system. In addition, the far side of the Moon may contain minerals and elements that are different from the front side of the Moon. These resources are of great significance for the future development and utilization of the Moon. Through the samples brought back by Chang'e-6, scientists can preliminarily assess the resource potential of the far side of the moon and provide a basis for future lunar resource development.
In just a few decades, China has gone from being a follower in the space field to becoming one of the frontrunners, an achievement that is inseparable from the hard work of scientific and technological workers and the continuous investment of the state. The successive successes of the Chang'e project have not only promoted the progress of science and technology, but also stimulated our imagination of the infinite possibilities of the universe. Let's wait and see what surprises and breakthroughs China's aerospace will bring next. What kind of surprises do you think the Chang'e-6 sample will bring to mankind? Welcome to add a discussion in the comment area, thank you for watching, I am exploring the universe, we will see you next time.