This image shows a highly porous crust on the lunar surface, a consequence of fractures generated by billions of years of impact cratering. Credit: NASA/JPL-Caltech/ IPGP
From looking at the Moon’s surface, we know it has taken a beating from asteroids and comets pummeling its surface. But new details from the GRAIL mission reveal the lunar interior just below the surface has been walloped as well, and is almost completely pulverized. This surprising finding, along with the discovery of deep fractures, suggests that in its first billion years, the Moon may have endured a history of massive impacts, more than previously thought. By inference, this means Earth and other terrestrial planets in the Solar System endured huge early impacts, too.
“It was known that planets were battered by impacts, but nobody had envisioned that the [Moon’s] crust was so beaten up,” said Maria Zuber, Principal Investigator for the GRAIL mission. “This is a really big surprise, and is going to cause a lot of people to think about what this means for planetary evolution.”
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