China's Rover Reveals Moon's Hidden Depths

China’s Chang’e-4 mission to the dark side of the moon has
discovered signs of mantle material at the moon’s surface,
“effectively setting an ‘X’ on lunar maps for future explorers
seeking this not-so-buried geological treasure,” reports Scientific
American. From the report: China’s Chang’e-4 mission touched down
near the south pole on the lunar far side on January 3, 2019, the
first spacecraft ever to land intact on this largely unexplored
region of the moon. Consisting of a lander and rover, the mission
is still going strong today, with the rover — called Yutu-2 —
continuing its journey across the surface. On board are a variety
of instruments, and today in Nature scientists from the Chinese
Academy of Sciences in Beijing report the mission’s first
scientific results, suggesting lunar mantle material has at last
been located. “We found that the material of the Chang’e-4 landing
site is mainly composed of olivine and low-calcium pyroxene,” says
Dawei Liu, one of the paper’s co-authors. “This mineral combination
is the candidate mantle-derived material.” Chang’e-4 rests inside
the South Pole-Aitken (SPA) basin, which, at 2,500 kilometers
across, is one of the solar system’s oldest and largest known
impact craters. Specifically, the mission touched down in the
186-kilometer-wide Von Karman crater within this larger basin. Von
Karman was produced billions of years ago by the impact of a large
comet or asteroid; such collisions can excavate mantle material
from deep underground, allowing it to be scattered across the
surface by subsequent impacts. The mantle material was discovered
using the Visible and Near Infrared Spectrometer on Yutu-2, which
can ascertain the chemical composition of rocks by studying their
reflected light. Both olivine and pyroxene are believed to be among
the first minerals that froze out from the moon’s magma ocean as it
cooled, falling to its solid base deeper in the mantle. Because
previous surveys from orbit have revealed much of Von Karman’s
floor to be composed of lava from volcanic eruptions rather than
excavated mantle, the paper’s authors suspect the material detected
by Yutu-2 was actually blasted into Von Karman from the upper
mantle beneath another nearby impact structure, the
72-kilometer-wide Finsen crater.


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Source: *FS – All – Science News 2 Net
China's Rover Reveals Moon's Hidden Depths