A full moon is pictured above the Earth's horizon as the International Space Station orbited 262 miles over the Pacific Ocean off the coast of Japan. Credit: NASA |
The dusty surface of the moon — immortalized in images of Apollo astronauts’ lunar footprints — formed as the result of asteroid impacts and the harsh environment of space breaking down rock over millions of years. An ancient layer of this material, covered by periodic lava flows and now buried under the lunar surface, could provide new insight into the Moon’s deep past, according to a team of scientists.
“Using careful data processing, we found interesting new evidence that this buried layer, called paleoregolith, may be much thicker than previously expected,” said Tieyuan Zhu, assistant professor of geophysics at Penn State. “These layers have been undisturbed since their formation and could be important records for determining early asteroid impact and volcanic history of the moon.”
The team, led by Zhu, conducted new analysis of radar data collected by China’s Chang’e 3 mission in 2013, which performed the first direct ground radar measurements on the moon.
The researchers identified a thick layer of paleoregolith, roughly 16 to 30 feet, sandwiched between two layers of lava rock believed to be 2.3 and 3.6 billion years old. The findings suggest the paleoregolith formed much faster than previous estimates of 6.5 feet per billion years, the scientists said.