Final answer:
Earth's atmosphere is composed of five main layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The troposphere is the closest to Earth and where most weather occurs, while the ozone-rich stratosphere is the second layer. Nitrogen and oxygen are the primary gases in the atmosphere.
Step-by-step explanation:
The Composition of Earth's Atmosphere Layers
The atmosphere of Earth is divided into several distinct layers. Each layer has unique characteristics and plays a vital role in supporting life on our planet. Below is an overview of these layers:
- Troposphere: This is the lowest layer of the atmosphere, extending up to 12 km above sea level. It contains roughly 80% of the Earth's atmosphere by mass and is where most weather events originate. In the troposphere, air density and temperature decrease with height.
- Stratosphere: Located above the troposphere, this layer stretches from 12 to 50 km above sea level. It is home to the ozone layer, which absorbs harmful ultraviolet B rays. The presence of ozone is crucial as it protects living organisms from UV radiation.
- Mesosphere: This layer extends from 50 to 80 km above sea level. It is where meteors typically burn up upon entering Earth's atmosphere.
- Thermosphere: Extending from 80 to 700 km above sea level, the thermosphere is where the Northern and Southern Lights occur. It has very low air density and high temperatures.
- Exosphere: The outermost layer of the atmosphere, the exosphere extends beyond 700 km above sea level and gradually fades into outer space.
The primary gases within Earth's atmosphere are nitrogen (78.1%) and oxygen (21.0%), with minor gases like argon, carbon dioxide, and water vapor making up the remainder.