Chinese researchers have made new progress in studying lunar soil samples returned by the Chang'e-6 mission, finding fresh evidence to help unravel the mystery of the Moon's two different hemispheres, according to the China Geological Survey.
Observing from the Earth, the near side of the Moon has a large number of maria made of dark volcanic lava, while the far side is covered with bright highlands and has few maria.
This lunar dichotomy has prompted researchers at the Institute of Geology of the Chinese Academy of Geological Sciences to study impact melt fragments in the Chang'e-6 samples using the country's first homegrown ion probe.
"The ion probe must direct an ion beam onto a precise spot at the micrometer scale. It's like shooting a basketball into a hoop from 3,000 meters away. The beam then sputters out secondary ions, which are then analyzed with great accuracy. It's very challenging, but the device can achieve an isotopic analysis accuracy of a few parts per ten thousand," said Long Tao, deputy director of the Planetary Science Research Center at the institute.
Through this ultra-precise analysis, the research team linked the near-far side disparity to the colossal impact that caused the South Pole-Aitken basin -- the largest, deepest and oldest impact feature on the moon -- about 4.3 billion years ago.
"The main reason for this difference is most likely linked to this massive impact, which stirred the material on the far side. This ultimately resulted in the lunar samples we collected from the South Pole-Aitken basin being more radioactive than samples from the more primitive lunar crust," said Che Xiaochao, an associate researcher at the institute.
In 2024, the Chang'e-6 probe made history by collecting 1,935.3 grams of lunar far-side samples from the South Pole-Aitken basin and bringing them back to Earth.
Chinese scientists uncover new clue to Moon's two-face mystery in Chang'e-6 samples
Chinese scientists uncover new clue to Moon's two-face mystery in Chang'e-6 samples
