Moon’s hidden face yields clues to a unified Lunar timeline

Scientists have achieved a major advance in understanding the moon’s history after confirming that impact cratering rates on both the near and far sides of the lunar surface are largely the same, paving the way for a single, globally consistent lunar chronology.

According to a report by Science and Technology Daily, researchers found that asteroid and meteorite impacts on the moon followed a steady, long-term decline rather than occurring in sharp, dramatic bursts as previously suggested.

The breakthrough comes from a study led by the Institute of Geology and Geophysics at the Chinese Academy of Sciences, which revisited and updated the long-standing lunar impact crater model using high-resolution remote sensing data. The findings were published in the journal Science Advances.

Determining the age of lunar surfaces is essential for decoding the moon’s geological evolution. For decades, scientists have relied on counting impact craters to estimate ages in areas where samples were unavailable, assuming that surfaces with more craters are older. However, this approach was based solely on samples collected from the moon’s near side, with the oldest rocks dating back about 4 billion years.

This gap left major questions unresolved, including debates over whether the moon experienced a sudden spike in impacts during its early history, often referred to as the Late Heavy Bombardment.

That uncertainty began to clear in June 2024, when China’s Chang’e-6 mission returned 1,935 grams of lunar material from the Apollo Basin within the vast South Pole-Aitken Basin on the moon’s far side. The samples included relatively young basalt estimated to be around 2.8 billion years old, as well as much older norite dating back roughly 4.25 billion years.

Researchers said the ancient norite likely formed from magma that crystallized after the colossal impact that created the South Pole-Aitken Basin—the largest and oldest known impact structure on the moon. These rocks have provided a crucial reference point for reconstructing the moon’s earliest history.

Using detailed remote sensing imagery, the team mapped crater densities across the Chang’e-6 landing site and the wider basin area. They then combined this data with existing sample records from NASA’s Apollo missions, the Soviet Luna programme, and China’s Chang’e-5 mission to build a revised and more complete lunar impact timeline.

The analysis showed that crater densities on the far side fall well within the confidence range of models previously derived from near-side data. This, researchers say, confirms that impacts were evenly distributed across the moon.

“The results demonstrate that the impact flux was essentially uniform over the entire lunar surface,” said lead author Yue Zongyu, a researcher at the institute. “This provides a solid scientific foundation for establishing a unified global lunar chronology.”

Yue added that the study highlights the scientific importance of the Chang’e-6 mission and significantly refines understanding of the moon’s impact history. The updated timeline is expected to improve age estimates not only for the moon but also for the surfaces of other planets and moons across the solar system.