Chinese scientists have accurately determined for the first time that the Apollo Basin on the moon was formed 4.16 billion years ago through high-precision geochronology of lunar soil samples from the Chang'e-6 mission. This discovery provides key evidence for revealing the timing of the Moon's Late Heavy Bombardment, and the related results were published online on August 20th Beijing time in the international academic journal Nature Astronomy. According to researchers, during the early stages of lunar formation, there were intense small celestial body impact events, and the widely distributed giant impact basins with a diameter of over 300 kilometers on its surface are the most intuitive geological record. The period during which these impact basins were formed is known as the "Late Heavy Bombardment Period" of the Moon in academia. Researchers have stated that the Apollo Basin, where China's Chang'e-6 sampling site is located, has a diameter of approximately 540 kilometers. As the largest secondary impact structure in the lunar South Pole Aitken (SPA) Basin, its formation age is closely related to the "late heavy bombardment period". Xu Yigang, an academician of the CAS Member and a researcher of the Guangzhou Institute of Geochemistry of the Chinese Academy of Sciences, together with Sun Yat sen University, Hong Kong University and foreign collaborators, found three special rock fragments of 150 to 350 microns in only 3.5 grams of lunar soil. These rock fragments are impact melted rocks produced during the formation of the Apollo Basin, and are the most ideal "rock clock" for recording impact events. The research team accurately determined the age of the rock debris, and combined various information such as remote sensing images and geochemical data to ultimately confirm that the 4.16 billion years recorded by the rock debris is the formation age of the Apollo Basin. (New Society)