Earth's Atmospheric Layers
Earth itself is comprised of many different layers, but the atmosphere around Earth also has several layers. Each layer has its own unique qualities, from the one closest to the ground to the boundary with outer space. Scientists and those who study aerospace topics have given each layer a name and studied them to better understand what makes up our atmosphere and each layer's individual role.
The first and lowest layer of the atmosphere is known as the troposphere and begins at the ground level. It goes up to about 33,000 feet above sea level, and this is where all humans and animals exist and thrive. This is the layer where all weather occurs, so every storm, tornado, or hurricane is formed within the troposphere. You'll see most clouds within this layer because almost all of the water vapor in the atmosphere is located here. As you go higher up in this layer, you'll notice that the air pressure begins to drop and temperatures begin to get colder.
- The Troposphere: This page contains information, fast facts, and a quiz about the troposphere.
- The Atmosphere: Click here for a diagram of the atmosphere and information about each layer.
- Clouds Above the Troposphere: Learn more about clouds and how they're formed high above this important layer of earth.
- Discovery Timeline: This page features a timeline showing important dates in the history of discovering the different atmospheric layers of earth.
The second layer around Earth is called the stratosphere, and it goes from the very top of the troposphere to about 30 miles above the ground. This layer is where the ozone layer is found, and its role is especially important in protecting Earth from the harmful UV rays from the sun. In contrast to the troposphere, this layer begins to get warmer as you go up higher rather than colder. The air is much more stable, and there are fewer updrafts, making it the ideal place for large jets and airlines to fly thanks to its low turbulence level that provides a smooth, safe ride. You will find the jet stream right at the border between the troposphere and the stratosphere.
As you go up, the next layer is known as the mesosphere. This layer extends to a height of about 50 miles above the earth. In this layer, most meteors will burn up before they hit the ground. Temperatures get colder the higher you go, and this layer actually experiences the coldest temperatures in all of the layers of Earth's atmosphere, reaching as low as -130 degrees Fahrenheit at the top. This layer does not produce enough oxygen for humans to breathe because the air is much too thin.
In the thermosphere, much of the sun's UV radiation and X-rays are absorbed. This creates extremely high temperatures that go as high as hundreds or even thousands of degrees. This layer of Earth's atmosphere is very similar to outer space, which is why many satellites orbit the earth within this layer. The beautiful Northern Lights happen here, too.
- The Thermosphere: This link provides an in-depth description of the thermosphere.
- Layers: NOAA explains the various layers of Earth's atmosphere at this website.
- The Northern Lights: Learn more about the Northern Lights and how they're formed here.
- The Thermosphere: NASA offers information about this layer of the atmosphere on this page.
The layer of Earth's atmosphere known as the ionosphere is actually a combination of areas within the mesosphere and thermosphere where the sun's energy has loosened electrons from atoms and molecules. As this happens, they become electrically charged and create something called ions. These ions are how the ionosphere got its name, and this layer has special attributes all its own. While it's not technically an official layer of Earth's atmosphere, it is still an essential part because of its ability to create ions and process the sun's energy.
- Earth's Ionosphere: This website explains more about how the ionosphere works and how it interacts with energy.
- Ionosphere: Click through these pages to learn more about Earth's ionosphere.
- The Earth's Ionosphere: This page provides diagrams and in-depth information about how the ionosphere functions.
- The Atmosphere: National Geographic takes a closer look at Earth's atmosphere and its many layers.
Many of those in aerospace exploration consider the exosphere to be the final layer of the atmosphere before entering outer space. The air up here is extremely thin, and it is much more space-like than any other layer before it. The air within the exosphere is slowly leaking into space, so there is not a definitive boundary to determine where it actually ends. It is estimated that the exosphere is anywhere from about 62,000 miles to upwards of 120,000 miles above Earth's surface.