We know how the gravitational pull of our Moon causes seas and lakes to rise and fall as tides on Earth. Similarly, the Earth’s gravitation too has an impact on the Moon. Scientists have known this for a while. However now, they have discovered that Earth’s gravitational pull is opening up faults in the lunar crust.

Lead author of the study, Thomas Watters, concedes that the finding was a big surprise, in spite of knowing about the close relationship between the Earth and Moon that goes back to their origins. So Earth is still shaping the Moon.

Thomas Watters works as a planetary scientist at the Smithsonian Institution’s National Air and Space Museum in Washington, D.C.

Researchers arrived at this conclusion after analyzing data from the LRO or the Lunar Reconnaissance Orbiter of NASA, which was launched in 2009. A year later, it helped scientists learn the Moon was shrinking. Images taken by the spacecraft revealed 14 lobe-shaped fault scarps or cliffs that were formed probably as the hot interior of the Moon cooled and contracted, forcing the solid crust to buckle.

LRO has been able to find more than 3,200 of these faults in the last 6 years in orbit. These cliffs are usually many meters high and less than 10 kilometers or 6 miles long. These are the most common tectonic features on the moon.

Now researchers are telling us that the Moon’s cooling isn’t the only reason for the formation of these fault scarps. If it was, then the forces of contraction should be equal in strength in all directions. Orientation of the cliffs should have been random. But there is evidence now that suggests that the fault scarps don’t have random orientations. “There is a pattern, and so something else is influencing their formation, something that’s also acting on a global scale”, says Watters. “That something is the Earth’s gravitational pull”, he adds.

Their findings have been published in the October issue of the journal Geology.