The Mesosphere

The mesosphere is the third layer of the Earth's atmosphere, located above the stratosphere and below the thermosphere. It extends from about 50 kilometers (31 miles) to 85 kilometers (53 miles) above the Earth's surface. The mesosphere is characterized by decreasing temperatures with increasing altitude.

Key Concepts to Understand:

Temperature: The mesosphere is the coldest layer of the Earth's atmosphere, with temperatures decreasing with altitude. The top of the mesosphere, known as the mesopause, has temperatures as low as -90°C (-130°F).
Atmospheric Composition: The mesosphere is primarily composed of molecular nitrogen (N2) and molecular oxygen (O2). It also contains small amounts of ozone (O3) and other trace gases.
Mesospheric Clouds: Noctilucent clouds, also known as polar mesospheric clouds, are occasionally observed in the mesosphere. These clouds are made of tiny ice crystals and are most visible during the summer months at high latitudes.
Role in Earth's Atmosphere: The mesosphere plays a crucial role in protecting the Earth from meteoroids. When meteoroids enter the mesosphere, they burn up due to friction with the atmosphere, creating bright streaks of light known as meteors or shooting stars.

Study Guide:

When studying the mesosphere, it's important to familiarize yourself with the following key aspects:

Temperature trends in the mesosphere and the significance of the mesopause.
The composition of gases in the mesosphere and how it differs from the layers above and below it.
The formation and characteristics of noctilucent clouds.
The role of the mesosphere in protecting the Earth from meteoroids and the phenomenon of meteors.

Understanding the mesosphere is essential for grasping the larger concepts of atmospheric science and the interactions between different layers of the Earth's atmosphere.