For the first time, scientists have found pieces of a rare meteorite buried in rock samples collected from the far side of the Moon — an area never before visited by any sample-return mission. The fragments, retrieved by China’s Chang’e-6 lunar mission and brought back to Earth in June 2024, could hold clues to how asteroids once seeded the early Solar System with essential compounds such as water.
Researchers in China identified the unexpected debris while analyzing the freshly returned material from the Moon’s vast South Pole–Aitken Basin, one of the largest impact craters in the Solar System. The fragments appear to come from carbon-rich asteroids similar to Ryugu and Bennu — two bodies previously sampled by Japanese and U.S. missions that contain dust grains older than the Solar System itself.
“The Chang’e-6 mission had a clear list of scientific goals, but this finding wasn’t even on it,” says Yuqi Qian, a planetary scientist at the University of Hong Kong who was not part of the research team. “It’s such an unexpected and important discovery.”
The findings were published this week in the Proceedings of the National Academy of Sciences.
A Different Kind of Lunar Discovery
All earlier lunar missions have sampled material from the near side of the Moon — the face that always looks toward Earth. Those regions are smoother and covered with volcanic plains formed by ancient lava flows. In contrast, the Moon’s far side is rugged, heavily cratered, and scientifically mysterious.
The Chang’e-6 lander, launched by the China National Space Administration (CNSA) in May 2024, touched down inside the South Pole–Aitken Basin, a massive depression that covers about a quarter of the lunar surface. Scientists believe it formed when a giant asteroid struck the Moon roughly four billion years ago, gouging deep enough to expose material from the lunar mantle — the layer beneath the crust.
The mission’s primary goal was to learn why the far side differs so dramatically from the near side and to collect pristine geological samples from one of the oldest regions in the Solar System.
But the discovery of meteorite fragments — instead of purely lunar rock — took researchers by surprise.
Space Forensics
At first, the scientists assumed the samples came from the Moon’s mantle, since the chemical composition appeared unusual. But closer inspection revealed inconsistencies. When researchers analyzed levels of iron, manganese, and zinc, they realized the ratios didn’t match typical lunar material.
To identify the fragments’ true origin, the team compared the ratios of oxygen isotopes — oxygen atoms with slightly different masses — in the debris. These isotopic “fingerprints” can reveal which planetary body a rock came from.
“This approach is basically space forensics,” says Mang Lin, a geochemist at the Guangzhou Institute of Geochemistry (GIG), part of the Chinese Academy of Sciences, and one of the study’s authors. The analysis showed that the oxygen isotope pattern matched almost perfectly with samples from Ryugu and Bennu, suggesting that the lunar debris came from a similar asteroid.
Ancient Messengers
Both Ryugu and Bennu are known to contain pre-solar dust grains — particles that existed before the Sun and planets formed — as well as volatile compounds such as water and organic molecules. These types of asteroids are thought to have delivered many of the ingredients that made Earth habitable.
The new discovery implies that such asteroids also bombarded the Moon, potentially delivering water and other volatiles there as well. “These materials are extremely fragile and tend to disintegrate when they enter Earth’s atmosphere,” says Jintuan Wang, a co-author of the study and a researcher at GIG. “Finding them preserved on the Moon is extraordinary.”
Because the Moon lacks both an atmosphere and geological activity, it acts like a cosmic archive, preserving impact debris that would have been erased on Earth. Studying these fragments gives scientists a rare chance to reconstruct the Solar System’s early history.
Tracing a Lunar Catastrophe
Team leader Yi-Gang Xu, also of GIG, believes that studying additional Chang’e-6 samples could reveal the age of the meteorite fragments — and whether the same asteroid that created the South Pole–Aitken Basin was their source. Determining that link could clarify one of the Moon’s greatest mysteries: the origin of its colossal far-side crater.
If the meteorite fragments are indeed connected to that ancient impact, it would suggest that a single colossal collision four billion years ago not only reshaped the Moon but also delivered material from beyond the Solar System to its surface.
A New Window Into Solar System Evolution
Planetary scientists worldwide are calling the find one of the most significant lunar discoveries in decades. The samples offer a new way to study how volatile-rich asteroids helped shape the early Solar System — and perhaps even how Earth acquired its water.
“The Moon has once again surprised us,” Qian says. “It’s not just a passive witness in space — it’s an active recorder of our cosmic past.”
With more samples from Chang’e-6 still being studied in laboratories across China, researchers expect further revelations in the coming months — and perhaps new questions about how interconnected our Solar System truly is.
Reference:
Wang, J. et al. Proc. Natl. Acad. Sci. USA 122, e2501614122 (2025).
doi: 10.1038/d41586-025-03439-0