Why did lava flow on ‘cold and dead’ moon? Chinese scientists find clues

Volcanic eruptions may explain lava rocks retrieved during China’s Chang’e 5 lunar mission

The samples date back 2 billion years – long after the moon is thought to have cooled and hardened

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Scientists in China analysed rock samples from the Apollo and Chang’e lunar missions to better understand when the moon cooled and hardened. Photo: Handout

Published: 2:00am, 22 Oct 2022Updated: 3:46am, 22 Oct 2022

Scientists say lunar samples from China’s Chang’e 5 mission have helped them understand why lava still flowed on the moon 2 billion years ago – a time when the moon was thought to have cooled down completely.

Though the moon’s interior was cooling at the time, a lunar mantle increasingly rich in calcium and titanium – elements with relatively low melting points – may have helped sustain volcanic eruptions that produced the lava, according to a paper in Science Advances on Friday.

“Our study offers the first viable explanation for recent volcanic activity on the moon, and helps planetary scientists better understand its thermal evolution,” said lead author Chen Yi of the Institute of Geology and Geophysics in Beijing.

In 2020, China’s Chang’e 5 spacecraft collected 1.73kg (3.86lbs) of soil from the near side of the moon and brought it back to Earth for laboratory analysis.

These dark lava rocks turned out to be surprisingly young. While rocks returned by Nasa’s Apollo missions and the Soviet Luna missions were over 3 billion years old, the Chang’e 5 samples were formed just 2 billion years ago.

Scientists believe that the moon was formed 4.5 billion years ago as a magma ocean. Over the next 500 million years, it crystallised from the inside to form a structure with three layers – a core, a mantle and a crust – just like the Earth.

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China’s Chang’e 5 lunar lander finds water on the moon, but not as much as they hoped

Scientists in China performed a series of experiments to explain the Chang’e 5 rocks and why there was lava flowing to the lunar surface 2 billion years ago, long after the moon was thought to have cooled and hardened.

Why did lava flow on ‘cold and dead’ moon? Chinese scientists find clues

Volcanic eruptions may explain lava rocks retrieved during China’s Chang’e 5 lunar mission The samples date back 2 billion years – long after the moon is thought to have cooled and hardened

Volcanic eruptions may explain lava rocks retrieved during China’s Chang’e 5 lunar mission

The samples date back 2 billion years – long after the moon is thought to have cooled and hardened