Layers Of The Earth’s Atmosphere

Layers Of The Atmosphere

The Earth’s atmosphere is composed of five primary layers based on temperature:

• Troposphere: The lowest layer, where weather occurs, helping to distribute water and heat, which is essential for life.
• Stratosphere: Contains the ozone layer, which absorbs and protects us from the sun’s harmful ultraviolet (UV) radiation.
• Mesosphere: The middle layer burns up most meteors before they can reach the Earth’s surface, preventing them from causing harm. 
• Thermosphere: The second-highest layer absorbs high-energy X-rays and ultraviolet radiation from the sun, raising its temperature and creating the ionosphere, which allows for radio communication. It is free of clouds and water vapor.
• Exosphere: The outermost layer, acts as a transitional boundary with space and helps protect Earth from cosmic radiation and solar winds.

 

Temperature Changes In The Atmosphere

The temperature changes in the atmosphere vary with each layer, and the reasons for these changes differ:

Troposphere: Temperature decreases with altitude because it’s warmed by the Earth’s surface.

Stratosphere: Temperature increases with altitude due to the absorption of UV radiation by the ozone layer.

Mesosphere: Temperature decreases with altitude as there is little ozone and less air to retain heat. It is the coldest layer.

Thermosphere: Temperature increases sharply with altitude as sparse molecules absorb high-energy solar radiation.

Exosphere: Temperature can be very high due to solar radiation absorption, but the air density is so low that it wouldn’t feel hot.

 

Fun Facts

Here are some interesting facts about the atmosphere:

• The International Space Station orbits in the thermosphere.
• The troposphere contains about 75% of the atmosphere’s mass.
• The thermosphere can reach temperatures up to 2,500°C (4,500°F) or higher during the day.
• The exosphere contains hydrogen and helium, the lightest gases, which can escape into space.

 

Review

Let’s quickly recap what we learned about the layers of the atmosphere:

• Which layer of the atmosphere is closest to the Earth’s surface? Troposphere
• In which layer of the atmosphere does the ozone layer exist? Stratosphere
• Which layer is free of both cloud and water vapor? Thermosphere
• Which layer is the outermost layer of the Earth’s atmosphere? Exosphere
• Which is the coldest layer in the atmosphere?  Mesosphere