Unknown Story
Kuvakäsikirjoitus Teksti
- Earth's Atmospheric Evolution By Jennie Li
- The Atmosphere is an envelope of air, surrounding the earth and bound to the earth by earth's gravitational attraction.
- After the beginning of the Earth's formation, the atmosphere was only made up of hydrogen and helium, similar to the conditions of the sun. The conditions didn't last long.
- Large amounts of water vapor from erupting volcanoes condensed into cooled down.
- About 3.5 billion years ago, after oceans and lake were created, the oceans absorbed a lot of carbon dioxide.
- About 2-3 billion years ago, few of the living things began to use the sun's energy to turn CO2 gas and water into sugar and oxygen.
- By 600 million years ago, a protective layer upper layer of the atmosphere called the ozone had formed.
- About 400-500 million years ago the first land plants appeared on Earth.
- Homo sapiens have roamed the Earth for about 200,000 years, during that time, the atmosphere had 78% nitrogen and 21% oxygen
- In the most modern atmosphere, the amount of carbon dioxide gas is less then 1%, an increase of 23% from 1959 levels.
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