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Modern climate change

Solar vs. Terrestrial Radiation

The sun is a blazing 5500 C and so it emits very intense radiation with short wavelengths. For this reason, solar radiation is sometimes also called shortwave radiation.

Most (44%) of the sun's radiation is in the visible wavelengths (0.4 (violet) to 0.7 (red) micrometers - a micrometer, is one-millionth of a meter). Solar radiation falling outside of this range is not visible to humans, even though it is very intense. The sun's radiation peaks at about 0.5 micrometers, which corresponds to the color blue-green. Nearly 37% of the sun's radiation is between 0.7 and 1.5 micrometers (infrared wavelengths). Only about 7% of the sun's radiation is in the ultraviolet range (wavelengths less than 0.4 micrometers), but this is still enough radiation to cause damage to human cells and cause skin cancer.

The surface of the Earth is on average "only" about 15C (59F) and so the radiation it emits has long wavelengths. For this reason, the Earth's radiation is usually called longwave radiation, or sometimes terrestrial radiation. Terrestrial radiation is almost all in the infrared wavelengths, and it peaks between 5 and 25 micrometers.

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