LAYER CAKE OF AIR

Earth’s atmosphere extends about 6,000 miles (9,600 kilometers) above the surface of Earth, where we live. You can think of the atmosphere as having several layers. Most of our weather comes from winds, temperature changes, and water vapor in the layer nearest Earth’s surface. This layer is called the troposphere. Most of the clouds you see in the sky are floating in the troposphere. The stratosphere is the layer above the troposphere. Jet airplanes fly in the stratosphere because there are few clouds up so high and the ride is usually less bumpy. Earth’s ozone layer is in the stratosphere. The ozone layer absorbs, or soaks up, harmful rays from the Sun. These harmful rays would probably destroy life if they reached Earth’s surface. The atmosphere gets thinner and thinner in the next layers up, the mesosphere and thermosphere. The top layer of Earth’s atmosphere is the exosphere. The atmosphere ends here, about 6,000 miles (9,600 kilometers) above Earth’s surface. The thin air here gradually merges with outer space.