Understanding Earth’s atmospheric layers

View of the Earth’s atmosphere from space.

When you look up at the sky, what do you see? Clouds? Rain in the distance? Occasionally a high-soaring plane. But, did you know most of this activity happens just a few miles above the Earth’s surface?

The rest of the atmosphere, which comprises of five distinct layers, stretches several thousand feet high. In this article, we’ll break down the various layers of the Earth’s atmosphere and explore the exciting features of each one.

The layer closest to the ground is called the troposphere. This layer stretches from the planet’s surface to around 5 to 9 miles high, depending on latitude. This layer contains the air we need to live and 99 percent of the planet’s water vapor. It is also where most weather happens.

Cumulonimbus cloud stretches to the lower fringes of the stratosphere over a city.

The next layer is the stratosphere, stretching as high as 31 miles above the surface. The stratosphere is exceedingly important since it houses the ozone layer, which protects all living organisms from harmful UV rays emitted by the Sun. Jet planes and towering cumulonimbus clouds usually reach the lower levels of the stratosphere.

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Reaching 50 miles from the surface is the mesosphere. Meteors flare up into bright fireballs in this layer, and at the higher reaches, temperatures can fall to a frigid -121 degrees Fahrenheit — the coldest temperatures in the atmosphere. Noctilucent clouds also appear at this level.

Noctilucent clouds appear high in the mesosphere. They are extremely rare clouds that usually have a bluish or silvery appearance.

The fourth layer is called the thermosphere stretching 440 miles from the surface. Thermometers stop working in this layer due to low air density. Temperatures in the upper thermosphere can range from about 500° C (932° F) to 2,000° C, but if you step outside without a spacesuit, you will freeze in seconds. The International Space Station orbits here, and it’s also where auroras appear.

Finally, we come to the exosphere, the final boundary before the reaches of outer space. This layer reaches 6,200 miles from Earth. Most of our satellites orbit at this level, where solar winds whip around the planet.