Earth's surface receives energy from processes in Earth's interior and from the Sun. Heat from the interior comes from radioactive elements in the mantle and core, tidal kneading by the Moon and Sun, and residual heat from the earth's formation. This interior heat is radiated through the surface at a global rate of 3 × 10¹³ watts (W)—about .07 W per square yard (.06 W/m²). The Sun, in contrast, provides 1.73 × 10¹⁷ W, 5,700 times more power than Earth radiates from within and about 30,000 times more than is released by all human activity. Clouds, air, land, and sea absorb 69% of the energy arriving from the Sun and reflect the rest back into space. The ocean, which covers about 70% of the earth's surface, does about 70% of the absorbing of solar energy.

Between its absorption as heat and its final return to space as infrared radiation, solar energy takes many forms, including kinetic energy...