The Atmosphere and Its Layers

Atmosphere Definition and Function

• The atmosphere is the layer of gases surrounding the Earth or other celestial bodies.
• It acts as an envelope around the Earth, held in place by gravity.
• The atmosphere protects the Earth's creatures from ultraviolet wavelength rays and maintains the necessary temperature for human life.

Atmosphere Composition

• The atmosphere is a mixture of different gases, water vapor, and dust particles.
• The composition ratio varies depending on geographical conditions.
• Nitrogen (78%), oxygen (21%), and argon (0.9%) are the main components, with carbon dioxide (0.03%) and others making up the remaining part.
• Methane, neon, and phosphorus are present in small amounts (0.1%).
• Ozone gas is a crucial component, absorbing ultraviolet radiation and preventing it from reaching the Earth's surface.

Layers of the Atmosphere

• The atmosphere is divided into five layers based on temperature and density.

Troposphere

• The lowermost layer, with a height of approximately 18 km at the equator and 8 km at the poles.
• This layer is where all weather changes occur.
• Thickness is maximum at the equator due to heat transportation by convection currents.

Stratosphere

• Located above the troposphere, extending up to 50 km.
• Temperature remains constant up to 20 km, then increases due to the presence of ozone gas.
• Ozone gas acts as a filter, absorbing ultraviolet radiation and preventing it from reaching the Earth's surface.

Mesosphere

• Located between 50 km and 80 km.
• Temperature decreases with altitude, reaching -100°C at the top.

Thermosphere

• Contains electrically charged particles (ions) known as the ionosphere.
• Radio wavelength broadcasting occurs due to reflection from these layers.
• Temperature increases due to ultraviolet light presence.

Exosphere

• The uppermost atmospheric layer, with gases dispersed due to lack of gravitational force.
• Air density is low due to the far distance from the Earth's surface.

Importance of the Atmosphere

• Provides oxygen for breathing and carbon dioxide for plants.
• Essential for human life, providing air for living organisms to breathe.