31K views · 704 reactions | In 1952, Harold Urey showed that the Moon’s gravity and shape reveal limits on its internal temperature. If the Moon’s core ever neared the melting point of silicates, it should have reshaped like a fluid—yet it didn’t. That means the Moon’s moment of inertia, its resistance to rotation, holds clues to a rigid, uneven interior. Unlike Earth, the Moon bulges not just at the equator… but also toward Earth itself. | The Randall Carlson | Facebook