What is the Earth’s Atmosphere? | Types, Definition, Structure, Function & Facts

What is the Earth’s Atmosphere?

The Earth is surrounded by a layer of gas called the atmosphere. The atmosphere is vital to life on Earth and does much to help preserve life and keep it alive.

Earth’s atmosphere is the layer of gas, collectively known as air, held together by Earth’s gravity that surrounds the planet and forms its planetary atmosphere. Earth’s atmosphere creates pressure, absorbs most meteors and ultraviolet solar radiation, warms the surface through heat retention (greenhouse effect), allows life and water liquid exists on the earth’s surface and reduces extreme temperatures between day and night (day and night temperature variations).

A Big Blanket

The Earth’s protective atmosphere is like an excellent insulating blanket. It absorbs heat from the Sun and traps it inside the atmosphere, keeping the Earth warm, this is known as the greenhouse effect. It also keeps the Earth’s overall temperature fairly stable, especially between day and night.

That way, we’re not too cold at night and not too hot during the day. There is also a part of the atmosphere called the ozone layer. The ozone layer helps protect the earth from solar radiation.

This large blanket also helps train our weather and climate patterns. Weather prevents too much warm air from forming in one place and causing storms and rain. All of these are important for life and the Earth’s ecology.

Air

The atmosphere is the air that plants and animals breathe in order to survive. The atmosphere consists mainly of nitrogen (78%) and oxygen (21%). There are many other gases that are part of the atmosphere, but in much smaller quantities. These include argon, carbon dioxide, neon, helium, hydrogen, and more. Animals need oxygen to breathe and carbon dioxide is used by plants during photosynthesis.

Layers of Earth’s Atmosphere

Earth’s atmosphere is divided into 5 main layers:

Exosphere – The last and thinnest layer. It is 10,000 km above the Earth’s surface.

Thermosphere – The thermosphere is next to it and the air here is very thin. Temperatures can be extremely hot in the thermosphere.

Mesosphere – The mesosphere covers the next 50 miles outside the stratosphere. This is where most meteors burn at the entrance. The coldest place on Earth is at the top of the mesosphere.

Stratosphere – The stratosphere extends the next 32 miles through the troposphere. Unlike the troposphere, the stratosphere gets its heat from the ozone layer that absorbs solar radiation. As a result, it heats up as you move away from the Earth. Weather bubbles rise to the stratosphere.

Troposphere – The troposphere is the layer adjacent to the earth’s ground or surface. It has an elevation of about 30,000 to 50,000 feet. It’s where we live and even where planes fly. About 80% of the atmosphere’s mass is in the troposphere. The troposphere is heated by the Earth’s surface.

Where does Outer Space start?

There is no clear definition between Earth’s atmosphere and outer space. There are a few official guides, most of which are between 50 and 80 miles from the Earth’s surface.