Four and a half billion years ago, after Earth’s fiery birth, the infant planet began to radically reshape itself, separating into distinct layers. Metals — mostly iron with a bit of nickel — fell ...

This post is the second in a three-part series on how living creatures use the elements of the periodic table. Read the first post here, and learn more about the elements on NOVA's two-hour special, ...

Earth's core, the deepest part of our planet, is characterized by extremely high pressure and temperature. It is composed of a liquid outer core and solid inner core. The inner core is formed and ...