Lava flowed across the moon’s surface just 2 billion years ago, bits of lunar rock samples retrieved by China’s Chang’e-5 mission reveal.
Chang’e-5 is the first mission to retrieve lunar rocks and return them to Earth in over 40 years.
A chemical analysis of the volcanic rocks published Thursday in the journal Science, confirms that the moon remained volcanically active far longer than its size would suggest possible, researchers at Beijing's Chinese Academy of Geological Sciences reported.
International authors led by researchers said the Chang'e 5 lunar mission collected samples of young lunar basalt lavas from the Oceanus Procellarum region.
"Orbital data indicate that the youngest volcanic units on the moon are basalt lavas in Oceanus Procellarum, a region with high levels of the heat-producing elements potassium, thorium and uranium," the team wrote.
Alexander Nemchin, a geochemist at Curtin University and a co-author of the study reportedly said that previous moon missions retrieved plenty of lunar soil and rocks, but “nothing younger than around 3.1 billion years old.”
"Now it seems we can at least start to fill in that gap with this young basalt,” he added.
China’s Chang’e 5, the third Chinese probe to land on the moon, landed Tuesday on the Sea of Storms on the moon’s near side.
Its main task was to drill a 2-metre core of rock to collect samples about 170 kilometers East-northwest of Mons Rümker — a large volcanic complex — and use radioactive dating to determine the age.
The moon formed roughly 4.5 billion years ago. Lunar rocks from the Apollo and Soviet missions in the 1960s and 1970s revealed that volcanism on the moon occurred for the first billion years of its existence, with flows lasting for hundreds of millions of years.
The study did not show an abundance of radioactive elements that would have provided the heat necessary for late volcanism to occur, and scientists are still unaware of why lava was flowing on the moon so long after it formed.
The findings are compelling scientists to consider what other forces could have maintained volcanic activity on the moon.