Scientists studying lunar samples brought back by China's Chang'e-6 mission have identified rare meteorite relics that could reshape our understanding of mass transfer in the Solar System.

The study, published in the latest issue of the journal Proceedings of the National Academy of Sciences, was led by a research team from the Guangzhou Institute of Geochemistry (GIG) under the Chinese Academy of Sciences.

Using advanced techniques to examine mineral composition and oxygen isotopes, the researchers scrutinized lunar soil and confirmed that the fragments came from CI-like chondrites – a type of meteorite rich in water and organic materials that typically originates in the outer Solar System.

The CI chondrites are so rare on Earth that they account for less than one percent of all collected meteorites. In contrast to Earth, the moon has almost no atmosphere or plate tectonics, meaning it preserves a pristine record of ancient asteroid impacts – like a "natural archive."

The study implies that the Earth-moon system may have experienced more collisions from carbonaceous chondrites than scientists had previously estimated.

One of a number of scientific theories on the moon's origin, and the most widely accepted to date, proposes that Earth's closest companion came to be during a colossal cosmic collision. According to the giant-impact hypothesis, after a Mars-sized proto-planet named Theia smashed into a young Earth, debris blasted into its orbit that eventually clumped together to form the moon 4.5 billion years ago. 

This discovery not only indicates that material from the outer Solar System can migrate to the inner Solar System, but also has important implications for explaining the origin of water on the lunar surface, said Lin Mang, a researcher at GIG.

It also provides new directions for future research on the distribution and evolution of lunar water resources, he added.

Moreover, the study systematically established methods for identifying meteoritic materials in extraterrestrial samples.

In 2024, Chang'e-6 made history by bringing 1,935.3 grams of samples from the far side of the moon back to Earth. These samples were collected from the South Pole-Aitken Basin, the largest, deepest and oldest basin on the moon.

(Cover: The Moon, October 6, 2025. /China National Space Administration)