The middle layer of the Earth’s atmosphere is the mesosphere. Located above the stratosphere and below the thermosphere, the mesosphere extends from about 50 to 85 kilometers (31 to 53 miles) above the Earth’s surface. In this layer, temperatures decrease with altitude, making it the coldest atmospheric layer.
What is the Mesosphere?
The mesosphere is a crucial component of Earth’s atmosphere. It acts as a protective shield, burning up most meteoroids before they reach the Earth’s surface. This layer is characterized by decreasing temperatures, with the top of the mesosphere, known as the mesopause, being the coldest part of Earth’s atmosphere.
Characteristics of the Mesosphere
- Temperature: The temperature in the mesosphere decreases with altitude, reaching as low as -90°C (-130°F) at the mesopause.
- Altitude: It ranges from approximately 50 kilometers (31 miles) to 85 kilometers (53 miles) above the Earth.
- Density: The air in the mesosphere is thinner than in the lower layers, but still dense enough to slow down meteors.
- Composition: Primarily composed of nitrogen and oxygen, with trace amounts of ozone and water vapor.
Why is the Mesosphere Important?
The mesosphere plays a critical role in protecting Earth from meteoroids. As meteoroids enter the atmosphere, they encounter increased friction in the mesosphere, causing them to burn up. This natural barrier prevents most meteoroids from reaching the Earth’s surface.
How Does the Mesosphere Compare to Other Atmospheric Layers?
Understanding the mesosphere’s position and function is easier when compared to other atmospheric layers. Here’s a breakdown of the Earth’s atmospheric layers:
| Layer | Altitude Range | Temperature Trend | Key Characteristics |
|---|---|---|---|
| Troposphere | 0-12 km (0-7.5 mi) | Decreases with altitude | Weather occurs here; densest layer |
| Stratosphere | 12-50 km (7.5-31 mi) | Increases with altitude | Contains the ozone layer; jets fly here |
| Mesosphere | 50-85 km (31-53 mi) | Decreases with altitude | Burns up meteors; coldest layer |
| Thermosphere | 85-600 km (53-373 mi) | Increases with altitude | Auroras occur here; contains the ionosphere |
| Exosphere | 600 km (373 mi) and up | Gradually fades into space | Outermost layer; merges with outer space |
What Phenomena Occur in the Mesosphere?
The mesosphere is home to several unique phenomena:
- Noctilucent Clouds: These are the highest clouds in Earth’s atmosphere, visible only at twilight.
- Meteors: Often referred to as "shooting stars," these are meteoroids burning up upon entering the mesosphere.
- Atmospheric Tides: These are global-scale oscillations that occur due to gravitational forces and solar heating.
People Also Ask
What is the Coldest Layer of the Atmosphere?
The mesosphere is the coldest layer of the atmosphere. Temperatures can plummet to -90°C (-130°F) at the mesopause, making it significantly colder than the layers above and below it.
Why Do Meteors Burn Up in the Mesosphere?
Meteors burn up in the mesosphere due to the increased friction and heat generated as they travel through this layer. The air, although thin, is dense enough to cause meteoroids to incinerate before reaching the Earth’s surface.
How Does the Mesosphere Affect Weather?
While the mesosphere itself does not directly affect the weather, it plays a role in atmospheric circulation and dynamics. The interactions within this layer can influence the stratosphere below, which in turn affects weather patterns.
What is the Mesopause?
The mesopause is the boundary between the mesosphere and the thermosphere. It is the coldest point in the atmosphere, marking the transition to the warmer thermosphere above.
Can Planes Fly in the Mesosphere?
No, planes cannot fly in the mesosphere due to the low air density and extremely cold temperatures. Commercial aircraft typically fly in the lower stratosphere where conditions are more stable.
Conclusion
The mesosphere is a fascinating and essential part of Earth’s atmosphere. It serves as a protective barrier against meteoroids and hosts unique phenomena like noctilucent clouds. Understanding this layer helps us appreciate the complex dynamics of our planet’s atmosphere. For more on atmospheric layers, consider exploring topics on the stratosphere or the thermosphere for a deeper understanding of Earth’s protective envelope.