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What shape is the moon? When it's full, we'd all agree that it looks perfectly round. But careful measurements by a team of scientists have shown that's not the case.

Like many an Earth-bound observer, it turns out that our nearest neighbor in space is hiding a slight bulge around the waist. It's less like a ball and more like a squashed sphere, with a lump on one side.


That's according to Ian Garrick-Bethell, a planetary scientist at the University of California, Santa Cruz, who is the lead author of the newly published findings in 

"If you can imagine a water balloon flattening out as you spin it," Garrick-Bethell says, describing the slight "lemon shape" of the moon.


How did it get that way? It all goes back to a time when 

 between a very young Earth and an ancient body known as Theia. The crust solidified, but the moon's center was still largely molten.


: "Efforts to pinpoint the moon's exact shape have long been stymied by the presence of large craters on its surface that formed after the crust solidified. There have also been inconsistencies between its measurements and what we know about its past."
The 

 says Garrick-Bethell and his team were inspired by similar research in 

 by researchers from the University of Texas at Austin. They calculated how tidal heating caused by Jupiter's massive tug was causing warmer water under the ice crust on Europa.  Copyright 2019 NPR. To see more, visit https://www.npr.org.

Science

Like many an Earth-bound observer, it turns out that our nearest neighbor in space is hiding a slight bulge around the waist.

Scientists say the moon is hiding a lumpy middle

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