# Solar Energy Intercepted by the Earth

### S1.7e17

The average optical energy flux ( UV, visible, Infrared, with a blackbody spectrum around 5778K ) reaching the Earth at 1AU (149.6e9 meters from the sun ) is 1366 W/m² in space, varying from 1365.5 to 1366.5 W/m² over the 11 year solar cycle. The mean (average) radius of the Warth is R = 6371.0 km, so the area facing the sun is πR² or 1.275e14 m². Multiplied by the 1366 W/m² flux, that's 1.742e17 W or 174 petawatts.