Material from carbon-rich asteroids reached the lunar surface through ancient impacts, delivering water and volatile elements to the Moon, according to research published in the journal Icarus. Scientists analyzing soil samples returned by China’s Chang’e-6 mission from the Moon’s far side identified a rare rock fragment bearing an unusual chemical composition and mineral structure that points directly to an extraterrestrial origin, The Times of India reported.
Chang’e-6 Samples Reveal Extraterrestrial Fragment
Researchers studying the lunar soil brought back by the Chang’e-6 mission isolated a small rock fragment with an uncommon combination of minerals. The team classified the sample as a spinel-bearing, troctolite-like rock. It features olivine and plagioclase as primary minerals, accompanied by smaller amounts of spinel and troilite. Traces of iron and nickel were also detected within the matrix.
The texture and chemical makeup of the fragment depart sharply from typical lunar rocks. These anomalies prompted the research team to investigate whether the sample formed through an asteroid impact. The study marks the first reported identification of material originating from beyond the Moon within samples retrieved by the Chang’e-6 mission.
Chemical Signatures Point to Carbonaceous Chondrites
The fragment displays several chemical features rarely found in native lunar material. Olivine crystals inside the rock contain elevated levels of cobalt, nickel, chromium, and phosphorus compared to standard Moon samples. The fragment exhibits an atypical oxygen isotopic signature, meaning its oxygen composition differs from normal lunar rocks.
High levels of iridium provided another critical clue. Iridium is a metal frequently associated with material delivered from space. These combined characteristics, alongside the distinct texture of the sample, indicate that the fragment originated from an impact involving a carbon-rich asteroid. Researchers suggest the impactor likely resembled a carbonaceous chondrite.
Ancient Collisions Deliver Water and Volatile Elements
Carbonaceous asteroids carry significant amounts of water and other volatile materials that easily vaporize into gas. When these space rocks strike the lunar surface, they potentially deposit substantial quantities of water onto the Moon. The impact process simultaneously mixes extraterrestrial material with native lunar bedrock.
Data from the fragment indicate that portions of its olivine crystals may derive directly from the impacting asteroid. This mixing process offers a previously unidentified route for the formation of spinel-bearing troctolite on the lunar surface. The study notes that the collision preserves physical clues concerning both the impacting asteroid and the lunar norite it struck.
Frequently Asked Questions
Where was the rare rock fragment discovered?
The fragment was found in lunar soil samples collected from the Moon’s far side during China’s Chang’e-6 mission.
What journal published the research findings?
The study was published in the scientific journal Icarus under the title “Delivery of carbonaceous materials to the Moon.”
What specific metals were found in unusual quantities?
Researchers detected elevated levels of iron, nickel, cobalt, chromium, phosphorus, and high concentrations of iridium.