Courtesy MSNBC.com
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The atmosphere
A third of the sun's energy is reflected back into space after hitting
Earth's upper atmosphere, but two thirds gets through, driving Earth's
weather engine.
Solar input
A delicate balance of gases gives Earth its livable temperature. Known as
“greenhouse” gases because they trap heat inside the atmosphere, they
send a portion of that heat back to Earth's surface. The gases include
water vapor, carbon dioxide, methane and nitrous oxide.