The moon has a major effect on Earth by affecting the ocean tides, but it turns out our gravity has its own effect — and we’re apparently ripping some cracks into our lunar pal.

Space reports on some new research analyzed by NASA's Lunar Reconnaissance Orbiter (LRO). The study’s lead author, Thomas Watters, noted it was a “surprise” the Earth is still helping shape the moon’s structure, though it makes sense, since they have always played such a major part in one another’s origins. We knew it had happened in the past, but scientists didn’t know it was still occurring until now.

By imaging six years' worth of data, the study found 3,200 of these “fault scarps.” Some of these marks are up to 50 million years old, and some are still forming to this day. Researchers originally believed the marks were random, though now they’ve been able to start finding the patterns in the marks. The tidal forces are strongest in the areas of the moon farthest, and closest, to the Earth.

The LRO has allowed scientists to study the moon in greater detail, which led to the discovery. So what might this mean for a future moon base? These tidal forces could potentially cause “moonquakes,” which could be an issue for future settlers. Though some well-placed seismometers on the moon could probably detect them.

So, yeah, one more thing trying to kill us once we eventually set up shop in space. Yay?

(Via Space)