Earth: Atmosphere

What is atmosphere? We will explore the definition, composition, structure, and functions of the atmosphere, and why it is so important for our planet.

The atmosphere is the layer of gases that surrounds the Earth and extends from the surface to the edge of space. It is composed of mainly nitrogen (78%) and oxygen (21%), with traces of other gases such as argon, carbon dioxide, water vapor, ozone, and methane. The atmosphere is not uniform, but varies in temperature, pressure, density, and chemical composition depending on the altitude and location.

Atmosphere Vs Air

Air is the mixture of gases that we breathe, mainly nitrogen and oxygen, with traces of other gases like argon, carbon dioxide, and water vapor.

Air is a subset of the atmosphere, the part that we directly interact with and that greatly impact life. The atmosphere is a broader term that includes air and other layers of gases that have various functions and characteristics.

Layers of Atmosphere:

The atmosphere can be divided into five main layers based on the temperature changes with height. These are:

- The Troposphere: This is the lowest and thickest layer of the atmosphere, where most of the weather phenomena occur. It ranges from about 10 km at the poles to 18 km at the equator. The temperature decreases with height in this layer, reaching about -60°C at the top.

- The Stratosphere: This is the second layer of the atmosphere, where the ozone layer is located. It ranges from about 10 km to 50 km above the surface. The temperature increases with height in this layer, reaching about 0°C at the top. The ozone layer absorbs most of the harmful ultraviolet radiation from the sun, protecting life on Earth.

- The Mesosphere: This is the third layer of the atmosphere, where most of the meteors burn up as they enter the Earth's atmosphere. It ranges from about 50 km to 80 km above the surface. The temperature decreases with height in this layer, reaching about -100°C at the top.

- The Thermosphere: This is the fourth layer of the atmosphere, where the auroras (northern and southern lights) occur. It ranges from about 80 km to 700 km above the surface. The temperature increases with height in this layer, reaching up to 1500°C at the top. However, this layer is very thin and has very few molecules, so it does not feel hot to a human.

- The Exosphere: This is the outermost layer of the atmosphere, where some satellites orbit. It ranges from about 700 km to 10,000 km above the surface. The temperature varies with height in this layer, but it is very low and close to absolute zero. This layer gradually fades into outer space.

Functions of Atmosphere:

The atmosphere performs several vital functions for life on Earth. Some of these are:

- It provides oxygen for breathing and carbon dioxide for photosynthesis.

- It regulates the temperature of the Earth by trapping some of the heat from the sun (greenhouse effect) and reflecting some of it back to space (albedo effect).

- It protects the Earth from harmful solar radiation by filtering out most of it (ozone layer) and deflecting some of it (magnetic field).

- It transports water vapor and clouds around the globe, creating precipitation and weather patterns.

- It distributes nutrients and pollutants through winds and currents.

- It supports sound waves and radio waves for communication.

Conclusion:

As you can see, the atmosphere is a complex and dynamic system that plays a crucial role in sustaining life on Earth. Without it, our planet would be a barren and inhospitable place. Therefore, it is important to understand how it works to fully appreciate its significance, purpose and make best use of it.

Points to Ponder:

There are different layers of atmosphere which are performing specific functions for supporting and maintaining life.  

Why are layers performing these specific functions?
There is a whole system, can any system develop without thought?





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