Question

Discuss the structure of the atmosphere.

Short answer

The Earth's atmosphere is divided into five primary layers: the troposphere, where most weather events occur; the stratosphere, home to the ozone layer; the mesosphere, where meteors burn upon entry; the thermosphere, characterized by extremely high temperatures and containing the ionosphere; and the exosphere, with its light gases and the boundary of space

Step-by-step solution

Troposphere

Start by describing the troposphere, which is the lowest layer of the Earth's atmosphere. Discuss its characteristics, such as its depth, temperature gradient, and the presence of most weather phenomena.

Stratosphere

Next, detail the stratosphere, where the temperature gradually increases with altitude. Discuss the presence of ozone layer within this layer and its importance.

Mesosphere

Afterwards, describe the mesosphere, characterized by decreasing temperatures with increasing altitude. It's the layer where most meteors burn up when entering the Earth's atmosphere.

Thermosphere

Proceed to the thermosphere, a layer with an extremely high temperature that can reach up to 2000°C. However, it wouldn’t feel hot to a human in direct contact because of the near-vacuum state. It also contains the ionosphere, an area filled with charged particles.

Exosphere

Finally, the uppermost region of the Earth's atmosphere is the exosphere. It's primarily composed of light gases such as hydrogen, helium. The boundary of space lies within this layer.

Key concepts

Troposphere

The troposphere is the lowest layer of Earth's atmosphere, extending up to about 8 to 15 kilometers (5 to 9 miles) from the Earth's surface. This layer holds the majority of the atmosphere's mass and is where we experience weather. The temperature in the troposphere generally decreases with altitude, which is why mountain tops are typically cooler than the base.
Most of the clouds form in this layer due to the presence of almost all the water vapor in the atmosphere. This is also where air mixes to create winds and weather patterns.

• The temperature decrease rate in this layer is approximately 6.5°C per kilometer.
• It contains about 75% of the atmosphere’s mass.
• Turbulence and convection currents happen here.

Stratosphere

The stratosphere sits just above the troposphere, extending from about 15 kilometers to 50 kilometers (9 to 31 miles) above Earth's surface. Unlike the troposphere, temperatures in the stratosphere increase with altitude.
A critical feature of this layer is the ozone layer, which absorbs and scatters ultraviolet solar radiation, protecting life on Earth from harmful UV rays.

• Temperature increases with altitude due to ozone absorption of solar radiation.
• It is largely free of weather disturbances.
• Commercial airliners often cruise in the lower stratosphere to avoid turbulence.

Mesosphere

Above the stratosphere lies the mesosphere, which extends from about 50 to 85 kilometers (31 to 53 miles) above the Earth. Here, the temperature decreases with altitude once again, making it the coldest layer of the atmosphere, with temperatures reaching down to -90°C in its upper regions.
The mesosphere is where most meteors burn up upon entering Earth's atmosphere, creating spectacular meteor showers.

• Temperature decreases to around -90°C.
• Meteors burn up in this layer, causing "shooting stars."
• Scientists study this layer using sounding rockets and radar.

Thermosphere

The thermosphere extends from about 85 kilometers to 600 kilometers (53 to 373 miles) above the Earth. In this layer, temperatures can soar up to 2000°C or higher.
However, because the air is so thin, it wouldn't feel hot to us. The thermosphere contains the ionosphere, a region filled with charged particles, which play a crucial role in radio communication.

• Temperatures can reach up to 2000°C.
• This layer is where the auroras occur.
• The International Space Station orbits within this layer.

Exosphere

The exosphere is the outermost layer of Earth's atmosphere, stretching from around 600 kilometers to 10,000 kilometers (373 to 6,214 miles) above the planet. This region transitions into outer space.
In the exosphere, atoms and molecules are so far apart that they rarely collide with one another. It is composed mostly of lighter gases like hydrogen and helium.

• Considered the fringe of Earth's atmosphere.
• Contains very low density, mostly hydrogen and helium.
• The boundary with space is somewhat undefined, blending into the vacuum of space.