Scientists examining lunar soil collected during China’s remarkable Chang’e-6 mission have made an astounding discovery: rare meteorite fragments suggesting that both Earth and the Moon experienced significantly heavier bombardment by water-rich asteroids than previously thought. The Chang’e-6 probe, which successfully returned the first-ever samples from the Moon’s far side in June 2024, provided invaluable material for this research.
A recent in-depth study of just two grams of this precious lunar dust revealed microscopic clasts containing olivine, sharing an identical chemical signature with CI carbonaceous chondrites. What makes this particularly significant is that such fragile space rocks rarely survive their fiery descent through Earth’s dense atmosphere, making their preservation on the Moon a crucial find.
Extraordinary Asteroid Fragments Discovered
The research paper details how scientists meticulously sifting through the Chang’e-6 samples uncovered seven tiny relics of carbonaceous (CI) chondrites. These asteroids are known to be rich in both water and complex organic molecules. Detailed mineral and isotope analyses further corroborated that these minute grains were formed when a carbonaceous asteroid impacted the lunar surface, causing the material to melt and then recrystallize.
While such fragments are exceedingly rare on Earth, constituting less than 1% of all meteorites found, they surprisingly account for approximately 30% of the “exogenous” (originating from outside the Moon) material within the Chang’e-6 soil samples. This stark contrast highlights the Moon’s pristine environment for preserving ancient cosmic evidence.
Profound Implications for Water in Our Solar System
This groundbreaking discovery holds profound implications for understanding the origin of water and other volatile compounds in the inner solar system, including on Earth. It strongly indicates that these water- and organic-rich asteroids migrated inwards through the solar system, delivering a much larger quantity of essential volatiles to both Earth and the Moon than earlier estimates suggested.
The lunar samples offer a unique, unbiased perspective that helps correct the inherent limitations and selective nature of Earth’s own meteorite collection. Consequently, these findings propose that lunar water—identified by its distinct oxygen isotopes—might have primarily originated from such outer-solar-system impactors. This revelation could fundamentally reshape our understanding of the early, formative stages of our solar system.