Earth’s atmosphere is a layer of gases that surrounds the planet and is held in place by gravity. It is composed mainly of nitrogen (78%) and oxygen (21%), with small amounts of other gases such as carbon dioxide, water vapor, and neon.
The atmosphere is divided into five main layers based on temperature changes with altitude: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
The troposphere is the lowest layer of the atmosphere and extends from the surface of the earth up to an altitude of about 12 kilometers. It is where most of Earth’s weather occurs, and temperatures decrease with altitude.
Above the troposphere is the stratosphere, which extends from about 12 to 50 kilometers above the surface. The stratosphere is characterized by a layer of ozone, which absorbs harmful ultraviolet radiation from the sun.
The mesosphere is the third layer of the atmosphere, extending from about 50 to 85 kilometers above the surface. Temperatures in the mesosphere decrease with altitude and can reach as low as -90 degrees Celsius.
The thermosphere is the fourth layer of the atmosphere and extends from about 85 to 600 kilometers above the surface. It is characterized by high temperatures and ionized gases, which allow it to conduct electricity and create the auroras.
Finally, the exosphere is the outermost layer of the atmosphere and extends from about 600 kilometers to the edge of space. It is composed mainly of hydrogen and helium and merges gradually with the vacuum of space.
The atmosphere plays an important role in regulating Earth’s temperature and climate, protecting us from harmful radiation from the sun, and providing the air we breathe. It is also a dynamic system that interacts with the oceans, land, and living organisms on the planet in complex ways, shaping the planet’s weather patterns and biogeochemical cycles.
