According to photos captured by NASA's Lunar Reconnaissance Orbiter, the moon is slowly shrinking over time, which is causing wrinkles in its crust and moonquakes.
The moon doesn't have tectonic plates -- like Earth does. It instead has an interior that has cooled over the last several hundred million years, it has caused the surface to wrinkle as it shrinks.
According to CNN, there are now thousands of cliffs scattered across the moon's surface, averaging a few miles long and tens of yards high. The orbiter has taken photos of more than 3,500 of them since 2009.
To put it into perspective, today the moon is 50 meters "skinnier" because of this process. And as it shrinks, the moon actively produces moonquakes along the faults. Researchers re-analyzed seismic data they had from the moon to compare with the images gathered by the orbiter.
CNN continues that data from the seismometers placed on the moon during the Apollo 11, 12, 14, 15 and 16 missions revealed 28 moonquakes recorded between 1969 and 1977. Researchers compared the location of the epicenters for those quakes with the orbiter imagery of the faults. At least eight of the quakes occurred due to activity along the faults. This rules out the possibility of asteroid impacts or rumblings from the moon's interior.
This means that the Apollo seismometers recorded the moon shrinking, the researchers said. The study of Apollo seismic data and analysis of more than 12,000 of the orbiter's photos were published Monday in the journal Nature Geoscience.
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