The Moon was never a fully homogenized body like Earth, analysis of Moon rocks made by the Chinese rover, Yutu, suggests. The basalts the rover examined are a new type, chemically different from those retrieved by the Apollo and Luna missions 40 years ago.
Since the Apollo program ended, American lunar exploration has been conducted mainly from orbit. But orbital sensors mostly detect the regolith (the ground-up surface layer of fragmented rock) that blankets the Moon, and the regolith is typically mixed and difficult to interpret.
Because Chang'e-3 landed on a comparatively young lava flow, the regolith layer was thin and not mixed with debris from elsewhere. Thus it closely resembled the composition of the underlying volcanic bedrock. This characteristic made the landing site an ideal location to compare in situ analysis with compositional information detected by orbiting satellites.
"We now have 'ground truth' for our remote sensing, a well-characterized sample in a key location," Jolliff said. "We see the same signal from orbit in other places, so we now know that those other places probably have similar basalts."
"The diversity tells us that the Moon's upper mantle is much less uniform in composition than Earth's," Jolliff said. "And correlating chemistry with age, we can see how the Moon's volcanism changed over time."
@темы:
link,
Farsnews,
space news