The literal translation of the word atmosphere is "sphere of vapors". The Earth's atmosphere is a protective sphere of vapors, or air that surrounds the Earth and provides it with a layer of insulation from the harmful rays of the sun. It is a vital part of the Earth, and has changed dramatically since the beginning of time. The earth's atmosphere has gradually changed since the Earth's birth approximately 4.6 million years ago.

In the beginning, the Earth's composition was very different that how it exists today. A long time ago the Earth's atmosphere was very similar to today's Venus and Mar's atmosphere. It had about 95% carbon dioxide, 2-3% nitrogen, and very little, less than 1% oxygen. Today the Earth contains 79% nitrogen, 21% oxygen, and 3% water vapor. It is evident that there were many events that happened over billions of years that have contributed to this change in the Earth's atmosphere.

As oxygen became a greater part of the atmosphere the ozone shield emerged. The shield was formed when solar ultraviolet radiation forces the reaction for oxygen to form ozone, also known as 03. The ozone protects the Earth and it's inhabitants from the harmful radiation from the sun.

In addition, because it rained, there was less carbon dioxide in the atmosphere. The carbon dioxide was lost over billion of years, as the ocean formed there was a chemical reaction in which carbon dioxide and water formed carbonic acid. It is shown in the equation CO2 + H2O = H2CO3. The carbonic acid dissolved oceanic rock into sand, silt, and mud. It is evident because of this geochemical process occurred there is more carbon in the rocks and minerals and there is less in the Earth's atmosphere.

he Earth had developed so drastically because of the tremendous dust and gas cloud within the Milky Way galaxy. The Earth grew larger as huge meteorites hit it, and the surface was covered with dus

Some common words found in the essay are:
Venus Mar's, Earth's Atmosphere, earth's atmosphere, carbon dioxide, ultraviolet radiation, beginning earth's, changed dramatically, carbon dioxide water, process called, carbonic acid, water vapor, radiation sun, dioxide water,
Approximate Word count = 661
Approximate Pages = 3 (250 words per page double spaced)