The moon is shaped less like a ball and more like a lemon, according to newly released data. We already pretty much knew the moon was a bit deformed because of gravitational tension with Earth. But a new map of the moon’s surface, which was captured using a laser altimeter, revealed that our closest celestial neighbor is a little rotund around the center, and tapers off on top and bottom.
The research was published in Nature this week, detailing how the moon has an appearance that more closely resembles a squashed circle—one of the researchers said the data suggests it sports a rather pronounced “equatorial bulge.” While there’s still said to be plenty of gravitational tension between Earth and the moon, scientists believe the moon actually took its shape due to tidal heating when it was much younger.
From our perspective down on Earth—and in pictures all over the Internet—the moon looks perfectly round, but our perspective is slightly skewed. The newfound data is actually a bit bemusing, because equatorial bulges are typically caused by objects that rotate, and the moon barely spins at all.
“If you can imagine a water balloon flattening out as you spin it,” said Ian Garrick-Bethell, a planetary scientist at the University of California, Santa Cruz. That’s essentially what the moon looks like, despite our years and years of assuming it was a perfectly round rock.