Hovering above the stratosphere and nestled beneath the mysterious expanse of the thermosphere, the mesosphere remains one of the Earth’s final frontiers in atmospheric science. This middle layer of our atmosphere, often overlooked yet crucially important, serves as the guardian of the Earth, burning up meteors before they can reach the surface and playing a key role in atmospheric chemistry. But what really is the mesosphere, and why does it matter?
In this post, we will ascend into the cold and lesser-known reaches of the mesosphere, exploring its characteristics, importance, and mysteries. From noctilucent clouds to the coldest temperatures within our atmosphere, join us on a journey to uncover the secrets of the mesosphere and understand its place in the tapestry of our planet’s atmosphere.
What is the Mesosphere?
The mesosphere is the third layer of the atmosphere. This layer is above the stratosphere and below the thermosphere. The word ‘mesosphere’ is derived from the Greek words ‘Mesos sphaira,’ which translates to ‘middle sphere.’ Meso means middle because it is the middle layer of the atmosphere. So, its name is the mesosphere.
What is the mesosphere made of? The mesosphere contains a layer of liquid iron and nickel. It also covers noctilucent clouds,” or polar mesospheric clouds. It is a solid layer covering 78% nitrogen and 21% oxygen. All other chemical species form the remaining 1%.
Height: It extends from about 50 to 85 km or 31-53 miles above the planet.
Characteristics of the mesosphere: Mesosphere is a cold and middle layer.
- The mesosphere extends from the top of the stratosphere to about 80 kilometers or 50 miles above the earth’s surface.
- It is vacuumed as it contains a limited amount of helium and hydrogen.
- Meteors burn in this layer due to friction with air molecules.
The mesosphere temperature: Fewer air molecules absorb incoming electromagnetic radiation from the sun. The carbon dioxide in the atmosphere also helps to make this layer.
- The temperature range is minus 5 degrees Celsius (-5°C) to minus 93 degrees Celsius (-93°C).
- Temperature decreases with altitude.
- It means the air gets colder as we go higher in the mesosphere, near about minus 93 degrees Celsius. Mesopause is the boundary between the mesosphere and the thermosphere. That’s why the mesosphere is the coldest layer of the Earth’s atmosphere.
Color: Various colors occur here because each layer’s particles and dominant gases act as prisms, filtering out specific light colors. The mesosphere layer commonly looks green and blue.
Temperature: At the base of the mesosphere, near the mesopause (the boundary with the thermosphere), the temperature can range from about -90 degrees Celsius (-130 degrees Fahrenheit) to -40 degrees Celsius (-40 degrees Fahrenheit). However, the exact temperature can vary depending on latitude, season, and time of day.
As you move higher up within the mesosphere, temperatures continue to drop. At the top of the mesosphere, near the stratopause (the boundary with the stratosphere), temperatures can reach as low as -120 degrees Celsius (-184 degrees Fahrenheit) or even colder.
Important facts about the mesosphere: Mesosphere has a lot of fascinating facts. Here are some common facts about it.
- It is less dense than a stratosphere due to the thin layer of gases.
- Aircraft cannot fly high enough to reach the mesosphere. Most aircraft fly in the troposphere and in the stratosphere, but they cannot fly in the mesosphere because they cannot reach that much height of the mesosphere.
- The mesosphere protects the earth’s surface from being hit by most meteoroids.
- It experiences atmospheric gravity waves and atmospheric tides.
- It protects the ozone layer from greenhouse gases and keeps other layers safe.
- An unknown type of lightning occurs in the mesosphere layer. It is referred to as ‘sprites’ or ‘elves.’
- This clear is very important for the earth’s protection. The mesosphere burns most matures and asteroids before reaching the earth’s surface.
Mesosphere Facts
The mesosphere is one of the layers of the Earth’s atmosphere, sitting above the stratosphere and below the thermosphere. It’s a fascinating and somewhat mysterious layer, primarily because it’s less studied than other atmospheric layers like the troposphere (where we live and which contains most of the weather) and the stratosphere (home to the ozone layer). Here are some key facts about the mesosphere:
Location and Thickness
The mesosphere extends from about 50 to 85 kilometers (31 to 53 miles) above the Earth’s surface. This range can slightly vary depending on the source.
Temperature
The mesosphere is characterized by decreasing temperatures with altitude. Temperatures can fall as low as -90°C (-130°F) near its upper boundary, making it the coldest layer of the Earth’s atmosphere.
Meteor Showers
The mesosphere is where most meteoroids burn up upon entering the Earth’s atmosphere, creating what we see as shooting stars or meteor showers. This happens because the mesosphere, despite its thin air, provides enough resistance to superheat and vaporize the meteoroids due to friction.
Weather Phenomena
It is home to unique weather phenomena, including noctilucent clouds. These are the highest clouds in the Earth’s atmosphere, situated in the mesosphere, and are visible from the ground under specific conditions, usually at twilight. They are made of ice crystals and appear to glow at night, a phenomenon known as “night shining.”
The mesosphere also experiences strong wind patterns and atmospheric tides, influenced by the sun and the lower layers of the atmosphere.
Research and Exploration
The mesosphere is difficult to study. It’s too high for balloons to reach and too low for satellites to orbit. This has earned it the nickname “the ignorosphere.” Research is conducted using sounding rockets, radar, and satellites passing through on their way to higher orbits.
Importance to Earth’s System
The mesosphere plays a crucial role in protecting the Earth from space debris. Causing meteoroids to burn up prevents many space rocks from reaching the Earth’s surface, acting as a protective shield.
It also contributes to the upper atmosphere’s chemistry, particularly in destroying and creating atmospheric compounds that can influence the climate and air quality in the lower layers.
Chemical Composition
Like the rest of the atmosphere, the mesosphere mostly comprises nitrogen and oxygen gases. However, the density of the air is much lower than in the troposphere, with fewer molecules to absorb and radiate the sun’s heat.
Pressure and Density
The pressure and density of the air decrease significantly with altitude in the mesosphere. This decrease in pressure and density is why the air is too thin to breathe, and the temperature drops.
The mesosphere, with its cold temperatures, meteor showers, and noctilucent clouds, adds a layer of complexity and fascination to our understanding of the Earth’s atmosphere. Its challenging conditions for study continue to intrigue and motivate scientists to develop new methods for exploration and research.
What happens in the Mesosphere?
The mesosphere is an important atmospheric layer where several interesting phenomena occur. Here are some key features and processes that take place in the mesosphere:
Temperature decrease: As mentioned earlier, the temperature decreases with increasing altitude in the mesosphere. The mesopause, the boundary between the mesosphere and the thermosphere, represents the coldest part of the Earth’s atmosphere.
Airglow: In the mesosphere, various chemical reactions emit faint light, known as airglow. These reactions involve the interaction of molecules and atoms with solar radiation, producing glowing emissions that can be observed from the Earth’s surface during nighttime.
Mesospheric winds: The mesosphere experiences strong winds known as mesospheric winds. These winds are mainly caused by gravity waves, disturbances in the atmosphere generated by weather patterns, or topographical features. Mesospheric winds can have significant impacts on atmospheric circulation and dynamics.
Meteoric ablation: The mesosphere is where most meteoroids (small celestial objects) enter the Earth’s atmosphere. When meteoroids encounter mesospheric gases, they undergo rapid heating and disintegration due to friction, known as ablation. This process creates visible meteors or “shooting stars” as they streak across the night sky.
Noctilucent clouds: Noctilucent clouds, also known as polar mesospheric clouds, form in the mesosphere at high latitudes during the summer. These thin, glowing clouds consist of ice crystals and can be observed in the twilight sky after sunset or before sunrise. They provide valuable information about the state and composition of the mesosphere.
What does the Mesosphere do?
The mesosphere plays several important roles in the Earth’s atmosphere and overall climate system. Here are some key functions of the mesosphere:
Absorption of Solar Energy: The mesosphere absorbs some of the Sun’s incoming ultraviolet (UV) radiation. This absorption helps protect the lower layers of the atmosphere, including the ozone layer in the stratosphere, from excessive UV radiation. The absorption of solar energy in the mesosphere also contributes to heating the upper atmosphere.
Airglow and Atmospheric Chemistry: The mesosphere is responsible for the production of airglow, a faint emission of light caused by chemical reactions in the upper atmosphere. These reactions involve interactions between atoms, molecules, and ions, contributing to the atmosphere’s overall chemistry. Studying airglow provides valuable insights into the composition and dynamics of the mesosphere.
Gravity Wave Generation: The mesosphere is a region where gravity waves are generated. Gravity waves are disturbances in the atmosphere that result from various sources, such as weather systems, mountains, or convective processes. These waves are crucial in transporting energy and momentum throughout the atmosphere and influencing atmospheric circulation.
Meteoric Input: The mesosphere is where most meteors burn up upon entering the Earth’s atmosphere. As meteoroids collide with the mesospheric gases, they undergo rapid heating and ablation, creating visible meteors or “shooting stars.” This input of meteoric material into the mesosphere has implications for the overall composition of the upper atmosphere.
Noctilucent Cloud Formation: Noctilucent clouds, which form in the mesosphere, provide insights into the state of the upper atmosphere. These clouds consist of ice crystals, primarily observed near polar regions during summer. Monitoring and studying noctilucent clouds help researchers understand changes in the mesosphere, including its temperature, moisture content, and dynamics.
The mesosphere is the protective layer of the earth. Modern technology and poisonous gas are affecting this layer day by day. Global warming and ice melting are proof of it. So we should be careful about it.
Our exploration uncovered the mesosphere’s vital roles, from protecting us against meteoroids to hosting phenomena like noctilucent clouds and sprites. This journey has illuminated the mesosphere’s physical characteristics and highlighted the importance of continued research and exploration in this under-studied region.
The mesosphere, with its extreme conditions and elusive nature, reminds us of the vast unknowns about our planet and the importance of scientific curiosity and exploration. May this dive into the mesosphere inspire you to look up at the night sky with a deeper understanding and wonder about the complex layers that protect, surround, and make up our atmosphere. Let’s keep our eyes on the stars and our minds open to the mysteries of the mesosphere and beyond.
References:
Venkat Ratnam, M.; Patra, A. K.; Krishna Murthy, “Tropical mesopause: Is it always close to 100 km?”. Journal of Geophysical Research.
“The Mesosphere – overview | UCAR Center for Science Education.”
IUPAC, Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Online corrected version: “mesosphere.”
Mesosphere (Wayback Machine Archive), Atmosphere, Climate & Environment Information ProgGFKDamme (UK Department for Environment, Food, and Rural Affairs).
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