It was in 1775 that Pierre-Simon Laplace developed his theories of tidal dynamics, formulating in the following year a set of equations to explain the phenomenon at a greater level of detail than ever before. Looking at the Moon on a frosty winter night, it's pleasing to realize that there is a mountainous region at the end of Montes Jura in Mare Imbrium that is called Promontorium Laplace. Surely the French astronomer and mathematician would have been pleased. One result of Laplace's calculations was his pointing out that the Moon's equatorial bulge was far too large to be accounted for by its current rate of rotation. Here we're dealing with conditions of formation of an object thought to have been the result of a collision between the Earth and a Mars-sized planet early in our system's evolution. I seldom write about the Moon in these pages, but today's story on its development catches my eye because it relates to the early history of our own world and the Solar System itself. For...