A cross-section through the Moon, highlighting the antipodal nature of lunar polar volatiles (in purple), and how they trace an ancient spin pole. The reorientation from that ancient spin pole (red arrow) to the present-day spin pole (blue arrow) was driven by the formation and evolution of the Procellarum — a region on the nearside of the Moon associated with a high abundance of radiogenic heat producing elements (green), high heat flow, and ancient volcanic activity. Illustration credits: James Tuttle Keane, University of Arizona.