Scientists resolves a long-debated anomaly in how nuclei spin

Atomic nuclei come in different shapes, varying from football-like ("prolate") to pancake-like ("oblate"). Prolate and oblate shapes have different moments of inertia. This is a body's resistance to having its speed of rotation altered by an external force. Atomic nuclei having different shapes with different moments of inertia implies that it takes different amounts of energy to spin different nuclei.