Moon rocks from China's historic mission suggest more recent volcanoes

Catch up quick: China's Chang'e 5 mission launched in November 2020 and returned about 3.8 pounds of lunar rock and soil to Earth a few weeks later.

• The spacecraft gathered samples on the near side of the Moon in Oceanus Procellarum, a region where basalt rock formed from volcanic eruptions.

What they found: The basalt rocks are about two billion years old, according to an analysis in one of three papers published today in the journal Nature and in a paper published in Science earlier this month. At that age, the samples are the youngest Moon rocks to be collected and directly dated.

• The finding suggests there were large volcanoes on the Moon more recently than previously thought — and that the lunar interior was still evolving two billion years ago.
• The samples contain less water than basalt formed from magma that erupted on the Moon between 2.8 billion and 4 billion years ago, researchers report in a second paper. That suggests the Moon's "youngest volcanism was not driven by abundant water in its mantle source," they write, and the Moon's mantle may have become dehydrated during prolonged volcanic activity.
• The magma that produced the basalt also appears to have had lower amounts of elements like potassium that generate heat through radioactive decay than scientists thought might be needed to produce magma, researchers report in a third paper. There are several theories of what could have kept the Moon volcanically active, including gravitational forces from Earth, Freda Kreier reports for Science News.

The big picture: Collecting a rock or soil sample from another world and returning it to Earth is a major technical feat. China is only the third country to successfully return samples from the Moon.

• U.S. astronauts carried 842 pounds of lunar rock and soil to Earth during the Apollo program.
• The Soviet Union collected samples from the Moon during several missions, including 6 ounces of soil from Mare Crisium, or “Sea of Crises," in 1976. It was the last lunar sample return mission before Chang'e 5.

Go deeper:

• China’s new Moon rocks hint at a violent history (The Daily Beast)
• The golden age of space-sample returns (Axios)