Chinese Scientists Link Moon’s Two Faces to Giant Impact Using Chang’e-6 Samples

Q: What dense impactor remnants might still be lurking deep beneath the Moon's largest crater?

The most likely dense remnants are pieces of the South Pole-Aitken impactor itself, especially iron-rich metal from its core, buried deep beneath the basin. That idea is supported by gravity and topography studies showing a large excess mass under the South Pole-Aitken Basin, the Moon’s biggest crater on the far side. Researchers have said the anomaly could be metal from the asteroid or protoplanet that struck the Moon and formed the basin, with some estimates suggesting the equivalent of a roughly 95-kilometer-wide iron-nickel core dispersed into the upper mantle. Scientists also caution that the buried mass may not be impactor metal alone. Another leading explanation is unusually dense lunar material, such as oxide-rich mantle or late-stage magma-ocean residues, concentrated beneath the basin by the giant impact and later geological evolution. The new Chang’e-6 sample research strengthens the broader case that the South Pole-Aitken impact reshaped the far-side crust and upper mantle long after the Moon’s magma ocean solidified. In that picture, what may still be lurking below the basin is either impactor metal, dense lunar interior material, or a combination of both — preserved as a deep gravitational “heavy spot” beneath the Moon’s largest scar.

2 articles · Updated · Global Times · Aug 16

Chang’e-6 lunar soil samples gave Chinese scientists fresh evidence that the moon’s stark near-far side split is tied to the ancient impact that formed the South Pole-Aitken Basin.
High-precision analysis of feldspathic impact-melt rocks found that the massive collision kept reshaping the lunar crust and upper mantle after the lunar magma ocean had already solidified.
That result challenges a single uniform magma-ocean explanation, suggesting the moon’s crustal and mantle reservoirs evolved differently across regions rather than through one global process.
The study also fills a major gap in lunar science because earlier sample returns came only from the near side, while the far side differs sharply in topography, composition and internal structure.