Over two centuries ago, Pierre-Simon Laplace, a French physicist and mathematician, noticed that the Moon's equatorial bulge is about 20 times larger than expected. Now, researchers are trying to find out why. Although the Moon looks quite spherical from the ground, it is flatter at its poles and wider at its equator, a trait known as an equatorial bulge. This characteristic is common; it's usually caused by an object's rotation around its axis. However, it's been noted that the Moon's bulge is about 20 times larger than it should be given its rotational rate of once per month... researchers at...