After the “Chang’e Stone”, what new mysteries does the moon have?

September 9, 2023 marks the first anniversary of the discovery of a new lunar mineral, Chang'e Stone, in the lunar soil samples collected by Chang'e-5. Chang'e Stone is the sixth new mineral discovered by humans on the moon, and China has become the third country in the world to discover a new mineral on the moon.

"Chang'e Stone" is a phosphate mineral found in lunar basalt particles, with associated minerals such as fayalite, clinopyroxene, ilmenite, anorthite, baddeleyite, cristobalite, troilite and glass. The discovery of "Chang'e Stone" not only enriches the types of lunar minerals known to mankind, but more importantly, opens a new chapter in lunar geological research and provides important clues for subsequent research on the origin and evolution of the moon. In the past year, what new research progress have scientists made on lunar soil? What new discoveries are worth looking forward to?

Lunar soil particles under a microscope

First, scientists have confirmed the important "reservoir" of lunar surface water. Chinese scientists have conducted research and analysis on the Chang'e-5 lunar soil samples through infrared spectroscopy and nano-ion probes, and found that there is a large amount of solar wind-derived water in the surface layer of Chang'e-5 minerals. They also estimated that the water content contributed by solar wind proton injection to the Chang'e-5 lunar soil is at least 170 ppm, which is equivalent to at least 170 grams of water per ton of lunar soil. This study confirms that lunar surface minerals are an important "reservoir" of water. The subsequent discovery of lunar surface "water reservoirs" can provide important support for human lunar scientific research, exploration and resource development activities, and can also provide resource guarantees for the future construction of lunar bases, human landing on the moon and staying on the moon.

Afterwards, scientists revealed the mystery of the origin of young volcanoes on the moon. Through the study of basalts in the Chang'e-5 lunar samples, Chinese scientists confirmed that lunar volcanic activity could have continued until 2 billion years ago, refreshing human understanding of lunar magmatic activity and thermal evolution history. The study found that the initial magma of the Chang'e-5 basalt contained higher calcium and titanium. It is speculated that this may be because the source area contains higher levels of monoclinic pyroxene-ilmenite pile crystals formed in the late magma ocean, which led to a lower melting point of the lunar mantle and induced the formation of young volcanoes. This research work quantified the thermal evolution process of the slow cooling of the moon's interior, providing a new explanation for the important scientific issue of "the origin of young volcanoes on the moon", which will deepen people's understanding of the origin and evolution of the moon.

Scientists have also revealed the secret of the moon's 800 million-year lifespan. The moon was formed about 4.5 billion years ago, but its mass is only about 1% of the earth. Such a small celestial body should theoretically cool down quickly, stop volcanic activity early, and become a dead planet.

Lunar basalt is magma formed by partial melting of the lunar mantle, and is a rock formed by cooling and crystallization on the lunar surface after volcanic eruptions. It provides an important window for understanding the composition and evolution of lunar mantle materials. The young basalt brought back by my country's Chang'e 5 provides a direct sample research opportunity for estimating the intensity of late lunar volcanic eruptions. The results of the study show that in the late lunar period, about 2 billion years ago, there were still large-scale magma eruptions. Putting the research results in the entire history of lunar volcanic eruptions, it can be found that the scale of lunar volcanic eruptions is not continuously reduced from early to late as imagined, but is reduced in the form of intermittent eruptions. These studies have extended the previously known geological life of the moon by about 800 million years, refreshing the traditional understanding of lunar evolution.

In addition, in March 2023, Chinese and British scholars measured water in the impact glass beads in the Chang'e-5 lunar samples, and found that the water content in the glass beads gradually decreased from the edge to the center; in May 2023, Chinese scientists discovered lunar glass materials of various types and different origins, and found natural glass fibers for the first time in the Chang'e-5 lunar soil; in July 2023, Chinese scientists studied key scientific issues such as thermal insulation and shear resistance of lunar soil samples, and affirmed the feasibility of using lunar soil to process and produce glass building materials on the lunar surface, providing reference for future lunar rovers, scientific research station construction, manned lunar exploration and other missions... These research results will serve my country's future lunar exploration missions from different angles.

Can lunar soil be used for agricultural planting? Can lunar soil be used to build houses? Can the moon provide resources for human settlement? Can the moon become the first stop for human space tourism? ... Research on lunar soil is still being carried out intensively, and it will surely reveal more mysteries of the moon for humans. (Author: Fan Shanshan Image source: CNNC review expert: Jiang Fan, deputy director of the Science and Technology Committee of China Aerospace Science and Technology Corporation)