Sunlight

Sunlight is a literally inexhaustible source of energy. Discover why (and how) the sun gives off light, how much sunligh... (more)

Sunlight is a literally inexhaustible source of energy. Discover why (and how) the sun gives off light, how much sunlight energy the earth’s surface gets in an average day, how much land we’d need to supply all our energy needs through sunlight, and some of the geographical problems with solar power. (less)