The Moon is massive enough that its gravity should shape it into a perfect sphere—but it’s not. Why? It has two distinct moments of inertia, meaning it's not evenly balanced. That tells us something strange: the Moon isn’t just spinning—it's locked in a 1:1 spin-orbit resonance with Earth. That’s why we only ever see one face. If it were perfectly symmetrical, Earth’s gravity wouldn’t have such a grip on it. So what stopped the Moon from smoothing out? This isn’t just a cosmic curiosity—it’s a c