Essay by PaperNerd ContributorCollege, Undergraduate May 2001

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Walk outside on an early Sunday morning. Take some time to admire the sunset, feel the wet dew beneath your feet, and then take a deep breath. Feel the soothing flow of air rushing into your lungs in an essential part of life, known as the breathing cycle. Such a crucial aspect of life would not be possible without the presence of the Earth's most precious resource, the Atmosphere. Unfortunately, people have begun to abuse this treasure and pollution is on the rise, a new enemy for the age-old protector of the Earth.

4.6 billion years ago, Earth was nothing more than a steaming ball of molten rock, an inhospitable place until about 3 billion years ago when plants began to make their appearance and create vast amounts of oxygen. Over time, the atmosphere developed a complex structure consisting of several different layers extending to an altitude of about 300 miles.

The troposphere is the closest layer at an altitude of about 10 miles. Nearly 80 percent of atmospheric mass is found at this layer. Next is the stratosphere, a very stable layer, at a height of about 10 to 30 miles above the surface. A lack of water vapor at this height inhibits the formations of clouds and is the ideal height for most commercial flights.

The mesosphere is 30 to 50 miles high and is the coldest region of the atmosphere reaching a chilly 198.64 degrees Kelvin. It is basically composed of the same particles as the other two layers. Above the mesosphere is a zone which consists of only one-billionth of the total atmosphere. This layer is known as the thermosphere and is the largest layer, stretching from 50 miles from the ground to 300 miles. Finally, the exosphere is the last layer at a staggering...