Forty-five years after astronauts landed on the moon, scientists said they have finally discovered its true shape: slightly flattened, with a bulge on one side.
“Like a lemon with an equatorial bulge,” said Ian Garrick-Bethell, a planetary scientist at University of California, Santa Cruz, and an author of the study, being published in the journal Nature. “If you can imagine a water balloon flattening out as you spin it.”
Efforts to pinpoint the moon’s exact shape have long been stymied by large craters on its surface that formed after the crust solidified. There also have been inconsistencies between its measurements and what is known about its past. For example, the moon barely spins, yet it appears to have the sort of equatorial bulge caused by rotation.