Researchers from Stanford University, including EFree Scientist Wendy Mao and her student Crystal Shi, the Geophysical Laboratory, HPSynC, and HPCAT performed experiments recreating to the varying extreme conditions of pressure and temperature within the early Earth. Their results support the theory expounded nearly a century ago that the Earth was formed in million-year stages. Within the Earth, the rocks and iron-rich materials melted from the heat of radioactive decay of certain isotopes. Subsequent cooling may have led to the heavier iron percolating downward to the core and lighter silicates staying on top [C. Shi et al., Nature Geosci. 6, 971 (2013)].