For decades, scientists have theorized that the movement of Earth’s tectonic plates is driven largely by negative buoyancy created as they cool. New research, however, shows plate dynamics are driven significantly by the additional force of heat drawn from the Earth’s core. The new findings also challenge the theory that underwater mountain ranges known as mid-ocean ridges are passive boundaries between moving plates. The findings show the East Pacific Rise, the Earth’s dominant mid-ocean ridge, is dynamic as heat is transferred.