Understanding The Earth’s Inner CoreForming a solid inner core requires more than just cooling—it depends on the precise chemistry of the molten material. Similarly, molten iron in Earth’s core must become “supercooled,” dropping roughly 800–1000 °C below its normal freezing point to solidify. However, geological evidence suggests Earth’s core has never cooled this far. “By studying how Earth’s inner core formed, we are not just learning about our planet’s past. The paper, “Constraining Earth’s Core Composition from Inner Core Nucleation,” appeared in Nature Communications on September 4, 2025.