Scientists at the National Astronomical Observatories of the Chinese Academy of Sciences reveal the composition of the lunar surface in a study published in the journal Nature on May 16. The South Pole Aitken Basin is a bit different than expected.
A nuclear theory states that the moon was not quite as cold and dead as it is today. Instead, it probably began as a huge, molten marble full of magma oceans. These oceans gradually cooled off, putting heavy minerals such as the green olivine or the low-calcium pyroxene deeper into the mantle. Less dense minerals swam up, giving the Moon a series of obvious geological strata like a cosmic onion. The crust, the top layer, usually consists of aluminum silicate or plagioclase.
"Understanding the composition of the Moon's mantle is crucial to test whether or not there has ever been a magma ocean," said co-author Li Chunlai in a press release. "It also helps drive our understanding of the thermal and magmatic evolution of the moon."
Understanding the composition of the mantle gives planetary scientists a better understanding of how the interior of other planetary bodies – including the Earth – could evolve.
The Chang & # 39; e 4-Lander landed originally in January at Von Kármán Crater, located on the bottom of the South Pole Aitken Basin. The lander then sent a rover, Yutu-2, equipped with a spectrometer that measures reflected light. By examining surface-reflected light as the rover rolled over Von Kármán, scientists were able to detect minerals and determine their chemical composition. Instead of seeing a lot of plagioclase, the rover found a dominance of olivine and pyroxene.
Since these elements are expected much deeper in the Earth's mantle, the authors suggest that they were ejected by a meteor that appeared on the lunar surface. The rover explores near the 72-kilometer Finsen crater, so the minerals may have been sprayed onto the surface during the formation of the crater.
Although NASA's Apollo missions landed people on the moon and Russia made concerted efforts to acquire moon samples during the 1970s, there had been no study of the Moon's mantle so far. This makes China's mission particularly important, but due to the complexity of studying lunar minerals on a planetary body hundreds of thousands of miles away, more work will be required to gain a more complete understanding of the shell's composition.