Layers of the Atmosphere

Layers of the Atmosphere
There are layers of the atmosphere that surround the earth and protect it from the harmful UV rays of sun. If you want to know more about the protective layers of the atmosphere, then read on...The earth is covered by an envelope of gases that protect it from the harmful UV rays. Have you ever wondered what lies between the clear, blue sky and space? There are layers of atmosphere that absorb the sun's energy and reflect it back into the space. In order to understand the atmosphere, scientists have divided it into different atmosphere layers. Each layer has a specific function that helps protect the earth and form the different weather conditions around the world. Let us go into the details of different layers of the atmosphere in order.

Composition of the Atmosphere

The atmosphere is the reason due to which there is life on earth. The composition of the atmosphere makes it possible for life to survive on earth. The composition of the atmosphere consists of various gases. Let us have a look at the gases in the atmosphere. The major gases in the atmosphere are nitrogen and oxygen. Nitrogen makes up 78% of the gases in the atmosphere and oxygen is about 21%. Other gases in the atmosphere make up the trace gases. The following is the list of gases that make up the composition of the atmosphere:
Nitrogen (N2)
Oxygen (O2)
Argon (Ar)
Carbon dioxide (CO2)
Neon (Ne)
Helium (He)
Methane (CH4)
Krypton (Kr)
Hydrogen (H2)
Nitrous oxide (N2O)
Carbon monoxide (CO)
Xenon (Xe)
Ozone (O3)
Nitrogen dioxide (NO2)
Iodine (I2)
Ammonia (NH3)
Layers of the Atmosphere in Order

We have gone through the list of gases that make up the composition of the atmosphere. Let us now have a look at the atmospheric layers of earth. Many people believe there are 4 layers of the atmosphere. However, this is not true as there are 5 atmospheric layers. These layers of the atmosphere in order of highest to the lowest are as follows:

Exosphere
This is the outermost layer of the atmosphere that is left out by many from the list. The exosphere extends from the excobase upwards. The composition of the exosphere is hydrogen and helium. The hydrogen and helium particles rarely collide as they are far away from each other. This layer is the thinnest layer of the atmosphere. It extends from the thermopause, a boundary that separates exosphere from thermosphere. It is in this layer the satellites sent from earth are in orbit. The ionosphere is present here overlapping both exosphere as well as thermosphere. It has influences over the radio propagation on the earth. The auroras seen in the poles is due to the ionosphere. You can get a few more thermosphere facts.

Thermosphere
The second layer after exosphere is the thermosphere. It is seen that the temperature of the thermosphere increases from the mesosphere. It becomes constant with height once it reaches the thermopause. This layer extends from the mesopause to 430 miles above earth. The high energy UV rays as well as the X-ray radiation from the sun are absorbed by the gaseous molecules in this layer. This is the reason behind temperature increase of this layer. Even though the temperature is really high, one would still feel cold in this layer. This is because the air in this layer of the atmosphere is very thin and there are very few gaseous molecules that will carry the heat to the skin.

Mesosphere
The third layer from the top is the mesosphere. It is in this layer where all the meteors from space burn up once they enter our atmosphere. This layer is the opposite of thermosphere. Instead of temperature increase, there is temperature decrease with the height in mesosphere. This layer of the atmosphere is the coldest and therefore water vapor is frozen into ice clouds here. These ice clouds are called as the Noctilucent clouds. The gases of the atmosphere like oxygen become thinner and thinner as they reach the height of mesosphere.

Stratosphere
The next layer is the stratosphere that is about 51 km. The stratopause works as a boundary between the stratosphere and the mesosphere. This layer of the atmosphere contains about 19% of the atmospheric gases. However, it contains very little water vapor. The temperature rises within the stratosphere, but they still remain below freezing point. The stratosphere contains 90% of the ozone layer.

Troposphere
The layer of the atmosphere that is closest the earth is the troposphere. This layer begins from the surface of the earth and moves up to 4 to 12 miles. As the height increases, the temperature in troposphere decreases. The transition boundary of troposphere and the stratosphere is called the tropopause. The troposphere is the only layer where the air is breathable. Weather conditions around the world take place in the troposphere. You can read more on layers of the earths atmosphere.

What is the Coldest Layer of the Atmosphere

A common question asked by many students is what is the coldest layer of the atmosphere. The coldest layer of the atmosphere is the mesosphere. There is a significant temperature drop in the mesosphere. To be more accurate it is the mesopause that is the coldest place in atmosphere as well as on earth. The temperature drops around -85 ° to -90° C in this layer.

This was all about the layers of the atmosphere in order. As you can see the atmospheric layers are very important for to the different climatic changes occurring on earth. The earth's atmosphere also protects life on earth from begin burned out due to the high energy ultra violet as well as X-ray rays from sun. Hope you have found useful information related to the layers of the atmosphere from the above paragraphs.

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