Earth Explorer
02-01-1995
Keeping Warm: Earth as Greenhouse
The sun gives off an enormous amount of energy as visible light and infrared radiation, as well as X rays, ultraviolet rays, and other types of radiation. Every second, scientists estimate, the sun releases the energy of 10 billion hydrogen bombs. From the sun, though, the earth is only a pinpoint 150 million kilometers (93 million mi) away. The earth receives just a tiny fraction of the sun's energy. In fact, the sun radiates into space about two billion times more energy than we intercept on earth.
Even so, earth's share amounts to an awesome amount of energy. It would take the power generated by 100 million Hoover Dams to ...