When China’s Chang’e-5 lunar spacecraft reached Earth last year, it brought along the first sample of moon rocks collected in more than four decades. A team comprising international researchers has been working hard to analyze part of this precious sample and learned that it features some of the youngest volcanic lunar material discovered to date.
The researchers discovered that the sample was around 1.97 billion years old. Although the moon today is volcanically inactive, over its 4.5-billion-year history it has witnessed significant volcanic activity which has played a key role in its development. The findings are published in the journal Science.
Helping understand Moon’s history
It’s imperative to determine the exact date of the sample to accurately date the moon’s geological history precisely. “Planetary scientists know that the more craters on a surface, the older it is; the fewer craters, the younger the surface. That’s a nice relative determination,” said researcher Brad Jolliff in a statement. “But to put absolute age dates on that, one has to have samples from those surfaces.”
Previous samples of volcanic activity on the moon, like those collected during the Apollo missions, were around three billion years old. And researchers have been able to date impact craters, where the lunar surface was hit by space rocks, to less than 1 billion years old. But there was a gap between these two periods which seems to have been filled now.
Useful data for further study of solar system
“In this study, we got a very precise age right around 2 billion years, plus or minus 50 million years,” Jolliff said. “It’s a phenomenal result. In terms of planetary time, that’s a very precise determination. And that’s good enough to distinguish between the different formulations of the chronology.”
This understanding doesn’t only come in handy for learning about our natural satellite. It can help astronomers get more insights about rocky planets in the solar system and beyond.
“The Apollo samples gave us a number of surfaces that we were able to date and correlate with crater densities,” Jolliff explained. “This cratering chronology has been extended to other planets — for example, for Mercury and Mars — to say that surfaces with a certain density of craters have a certain age.”
