Moon Rock Samples From Far Side Reveal Ancient Cosmic Collision Reshaped Lunar Interior

First Samples From the Moon's Far Side Rewrite Lunar History

Two landmark studies drawing on samples from China's Chang'e-6 mission have fundamentally changed our understanding of the Moon's four and a half billion year history. The mission, which returned nearly two kilograms of material from the lunar far side in June 2024, has delivered the first physical evidence from the hemisphere that permanently faces away from Earth.

Unified Lunar Timekeeping

A team led by Yue Zongyu at the Chinese Academy of Sciences confirmed for the first time that impact cratering rates on the Moon's near and far sides are essentially identical. By combining Chang'e-6 data with historical samples from Apollo, Luna, and Chang'e-5 missions, researchers built a revised chronology model that works globally rather than just for the near side. The study, published in Science Advances, also provides evidence that early lunar bombardment followed a smooth decline rather than the dramatic spike proposed by the Late Heavy Bombardment hypothesis.

A Giant Collision That Went Deep

A separate study published in the Proceedings of the National Academy of Sciences found that the enormous impact which created the South Pole-Aitken basin, one of the largest known impact structures in the solar system, did not merely scar the surface. High-precision potassium isotope measurements revealed that Chang'e-6 basalts are isotopically heavier than any previously collected lunar samples. Researchers attribute this to massive volatile loss caused by the extreme heat of the ancient collision, which penetrated deep enough to alter the Moon's mantle.

Solving the Two-Face Mystery

The depletion of volatile elements may have suppressed magma production on the far side, helping explain one of the Moon's oldest mysteries: why dark volcanic plains cover roughly ninety three percent of the near side but are largely absent on the far side. Together, these findings transform Chang'e-6 samples into a Rosetta Stone for planetary science, with the refined chronology models now serving as references for dating surfaces across the entire solar system.