As someone born after the last Apollo mission, it is exciting to see the world working to return to the Moon. And I mean the world.

From India to Israel to China and Russia, nation after nation is getting hardware to the Moon — sometimes with a bit more speed than intended. Among the new stars of lunar exploration is the Chinese series of Chang’e missions, which include the Chang’e 5-Ti mission, which is about to crash a rocket booster into the Moon and which returned a sample of rocks from the Oceanus Procellarum region in 2020. 

Using radiometric dating, researchers got an age of 2.03 billion years for this region, which is consistent with expectations. Where things get neat is in looking at the craters. Since rocks fall out of the lunar skies at a consistent rate across the Moon, we know that areas with fewer craters are younger for one reason or another, with things like lava filling craters and large craters periodically resetting regions by eradicating smaller craters. 

If two regions have the same cratering, they should be the same age, and new crater counts of the region around the Chang’e 5 collection site show that other regions of the Moon, with the same crater counts, are about 200 million years older than previously theorized. This shows the importance of getting actual measurements. While the entirety of the Moon is always cratered at similar rates, those rates aren’t constant with time, and it is from lunar samples that we can get a true understanding of our nearest neighbor.

More Information

China’s moon sample updates lunar chronology model (EurekAlert)

“Updated lunar cratering chronology model with the radiometric age of Chang’e-5 samples,” Zongyu Yue et al., 2022 February 14, Nature Astronomy