The rock samples brought back from Moon in December by China’s Chang’e-5 mission carry evidence of the most recent lunar lava ever analysed. The researchers used tiny fragments from the 2 kilograms of rock by the Chang’e-5 lander to confirm predictions about the Oceanus Procellarum region, where the spacecraft had landed.

Xiaochao Che and colleagues at the Sensitive High-Resolution Ion MicroProbe (SHRIMP) Center in Beijing led the Chang’e-5 dating analysis. However, they worked with a broad international consortium.

The data proves volcanism continued on the moon long after one might have expected. The researchers will now be thinking of new ideas for what kind of heat source might have sustained the behaviour.

Also read | China’s Chang’e-5 spacecraft returning to Earth with Moon samples: Report

Dr Katherine Joy, a co-author from the University of Manchester, UK, was quoted by the BBC as saying, “One of the other options we discuss in the paper is maybe the Moon was able to stay active longer because of its orbital interactions with Earth.”

“Maybe the Moon wobbled back and forth on its orbit, resulting in what we call tidal heating. So, a bit like the Moon generates ocean tides on Earth, maybe the gravitational effect of the Earth could stretch and flex the Moon to generate frictional melting.”

As per the scientists, the more craters they see on a surface, the older that terrain must be. Also, the presence of very few craters is suggestive of a surface that has been laid recently or has been remodelled. 

Professor Brad Jolliff, from Washington University in St Louis, US, who happens to be another co-author in the consortium is hoping that China will send its next sample return mission to an area of Moon’s far side called South Pole Aitken Basin.

Also read | Chinese spacecraft returns to Earth with rocks from Moon

“If Chang’e-6 goes to South Pole Aitken it will give us the age of the oldest big impact basin on the Moon, and that provides a very different part of the calibration, in the range of four to four-and-a-half billion years ago. We don’t know what the flux of big impactors was back then, and a sample from the South Pole Aiken Basin region has the potential to answer the question,” he was quoted by BBC. 

The Moon samples were collected by a robotic vehicle with the sample collection taking upto 19 hours, China’s space agency informed. Chinese space scientists have put the return capsule onboard the orbiting module for delivery back to Earth.