Moon: Earthlings, I live much longer than you think!

In the imagination of ancient people

Chang'e flies to the sky and goes to Guanghan

Accompanied by the osmanthus tree and the jade rabbit, he guarded the Moon Palace for a long time

now

Chang'e 5 directly brought part of the moon back to Earth

As the "Chang'e" of the scientific world

She continues to break through the boundaries of human cognition

Image source: CCTV.com - lunar soil particles under a microscope

Recently, Chang'e 5

A major mystery about lunar volcanic activity has been solved

Why did lunar volcanic activity continue for so long?

How does it do that?

Source: Schematic diagram of magma and thermal evolution of the moon at different times Institute of Geology and Geophysics, Chinese Academy of Sciences

The moon was formed about 4.5 billion years ago and its mass is only about 1% of the Earth. Like humans, the fatter the planet, the better its thermal insulation effect. The Earth's thermal insulation performance is so excellent that we can still experience its endless geological vitality on the surface today.

For a celestial body as small as the moon, theoretically it should have "shut down" long ago - that is, stopped its volcanic activity and became a "dead" planet.

Image source: Copyright Library

When did the moon become completely silent today? Previously, the scientific community generally believed that it was 3 billion years ago. However, the research of Chang'e 5 has delayed the active history of lunar geological movement by about 1 billion years.

Image source: NASA - Chang'e 5 lander on the moon

Lunar basalt is a rock formed by the partial melting of the lunar mantle (equivalent to the Earth's mantle), which was then erupted by volcanoes and cooled and crystallized on the lunar surface. When we look up at the moon, the dark parts are basalt.

International scholars have proposed two hypotheses for the partial melting of the continuously cooling lunar mantle: one is that radioactive elements generate heat, causing the lunar mantle to warm up; the other hypothesis is that if the water content is high, it will lower the melting point of the lunar mantle.

However, Chinese scientists' research on the Chang'e-5 basalt revealed that the lunar mantle source region is not rich in radioactive heat-generating elements and is very "dry", ruling out the above two hypotheses.

Therefore, why the lunar volcanic activity lasted so long has become an unsolved mystery in the new round of lunar research.

Image source: Chang'e collects soil on the moon

Using the lunar samples brought back by Chang'e-5, scientists successfully restored the initial magma composition of the Chang'e-5 basalt.

The study found that compared with the Apollo samples, the initial magma of the young Chang'e-5 basalt contains more calcium and titanium, which indicates that more calcium-rich and titanium-rich materials were added to the lunar mantle source region of the Chang'e-5 basalt.

This part of material is precisely the product of the late crystallization of the lunar magma ocean and has the property of being fusible. Its addition will significantly lower the melting point of the lunar mantle, inducing partial melting of the lunar mantle to form young lunar basalt.

Image source: Science and Technology Power

This shows that although the interior of the moon continues to cool slowly, the fusible components crystallized in the late stage of the lunar magma ocean are continuously added to the deep lunar mantle, which not only "replenishes calcium and titanium" for the lunar mantle, but also lowers the melting point of the lunar mantle, thereby overcoming the slowly cooling internal environment of the moon, triggering long-term lunar volcanic activity and continuously extending the "lifespan" of the moon.

END

Source: China Science Daily, CCTV.com, Institute of Geology and Geophysics, Chinese Academy of Sciences

Compiled by: Dong Xiaoxian