If you’ve ever climbed a mountain or been to the beach, you know that the atmosphere is different at different levels. This lesson explains how the structure of the atmosphere is really like a layer cake.
Imagine that you’re preparing for a rocket launch in which you and your crew will launch from the surface of the Earth in an attempt to repair the International Space Station.
While it may be hard to believe, you actually won’t be leaving the Earth’s atmosphere for this mission! This is because the atmosphere of Earth actually extends hundreds of miles above the surface. In this lesson, we’ll prep you for your mission by making sure that you’re familiar with each layer of the Earth’s atmosphere, starting at takeoff and ending with your rendezvous with the damaged satellite.
The starting point for your mission is the troposphere, the lowest level of Earth’s atmosphere. For the most part, this is where most of the aspects of the atmosphere that affect us on a daily basis occur.
We breathe the air of the troposphere with its mix of mostly nitrogen with some oxygen and carbon dioxide, and we experience the weather that occurs in its highest reaches. In fact, the troposphere extends 14.5 kilometers above sea level, meaning that even while in a commercial airliner, we never leave the troposphere.At only 14.5 kilometers up, you’re nowhere near close enough to be able to service the Space Station. However, considering that your rocket travels at 8 kilometers per second, which is a bit slow for a rocket, to be honest, you’ll be out of the troposphere in less than 2 seconds. In doing so, you’ll be one of a small few to leave that layer of the atmosphere.
Continue upwards and you’ll be in the stratosphere, the second of Earth’s layers of the atmosphere. Here you’ll find a few clouds, but the fact is that most of the weather takes place in the troposphere. Instead, you’ll find only two real markers of human activity in the stratosphere. The first of these is the condition of the ozone layer, a blanket of air that helps to keep ultraviolet light out of the lower levels of the atmosphere. This is particularly helpful, as ultraviolet light can cause some serious damage to much of the life on Earth.Second, you may see the distant jet trail of a spy plane.
Most spy planes, such as the infamous U-2, fly in the stratosphere to avoid being shot down by less capable planes. However, as rockets can still reach them, they are still in danger.Speaking of rockets in the stratosphere, as this layer of the atmosphere is only 40 kilometers from top to bottom, you’ll be through it in 5 seconds from the time you entered it.
I hope you remembered to dress warmly for the next layer of the atmosphere. The mesosphere comes next, and it is the coldest of the four layers of the atmosphere. It’s too far up to benefit from the warmth-catching abilities of the planet’s clouds, but too far down to be warmed directly by the sun. In any event, it stretches from the top of the stratosphere, or around 55 kilometers above the earth, for another 30 or 40 kilometers. This is also the start of the ionosphere, where trillions of charged atoms and molecules provide the network necessary for radio transmission to work. Still, as the region is only a few kilometers from top to bottom, your rocket makes its way through in another 4 seconds.
Thermosphere and Beyond
Less than ten seconds into your trip, and you are already in the layer of the atmosphere that will serve as your final destination. The thermosphere is the highest of the four main layers of the Earth’s atmosphere. It starts past the mesosphere, so about 100 kilometers or so above the Earth’s surface, and then continues for 600 kilometers. Like the mesosphere, it is also home to the ionosphere. However, it is also home to some of Earth’s satellites, as well as the International Space Station.
As a result, it is your final destination.That said, if you were curious, if your rocket kept going the extra two minutes or so to get out of the thermosphere, you’d find yourself in the exosphere. Up here are more satellites, but mostly the atmosphere gives way to the depths of space.
Let’s review. In this lesson we looked at the different layers of the Earth’s atmosphere.
There are five of them worth noting:
- The troposphere is the lowest level of Earth’s atmosphere and extends from the surface to about 14.5 kilometers.
- The stratosphere is the second of Earth’s layers of the atmosphere and extends for 40 kilometers past the Troposphere.
- The mesosphere comes next, and while it’s only another 30-40 kilometers from one end to the other, it is the coldest of the four layers of the atmosphere. It is also home to the lower part of the ionosphere, where trillions of charged atoms and molecules provide the network necessary for radio transmission.
- The thermosphere is the highest, extending for more than 600 kilometers. It is where the International Space Station is.
Beyond it is the exosphere.
When the lesson is finished, you may be able to:
- Identify the layers of the atmosphere
- Give information about the characteristics of each layer
- Recognize the conditions and objects that one might find in the four layers of the Earth’s atmosphere