Atmosphere - Layers

Layers

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The atmosphere around the earth is made up of layers that are distinguished by temperature.

The first layer closest to the earth is the troposphere. This layer contains about 75% of the total mass of the atmosphere. This is where all plants and animals live and breathe. Climate and weather also occur in this layer.

The next layer is the stratosphere. It extends to about 30 miles above the earth. Ozone in this layer stops many of the sun's harmful ultraviolet rays from reaching the earth. This layer plus the troposphere make up 99% of the total mass of the atmosphere.

The third layer is the mesosphere. The temperature can drop to -173 degrees Fahrenheit. This is where we see "falling stars," meteors that fall to the earth and burn up in the atmosphere. At certain times of the year, we can see many of these "falling stars" when the earth goes through the pieces of a broken comet.

The thermosphere layer has many temperature changes. Energy from the sun is absorbed and bounced back. The top of this layer can get to 441 degrees Fahrenheit.

The exosphere is the highest layer of the atmosphere. It extends to 40,000 miles above the earth's surface. The thermosphere and the exosphere together make up the upper atmosphere.

Radio waves transmitted from the earth bounce off tiny energy particles called ions, located in the upper atmosphere, and return to a different location on the earth. The upper atmosphere also contains the magnetosphere. This layer produces the beautiful "northern lights" or "aurora borealis."

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Last modified: Tue May 12 13:02:51 PDT 1998