The layers of earth’s atmosphere

Earth has four layers in its atmosphere.

The troposphere is 12km up, this is the layer closest to the earth and where the weather occur (clouds). The air is the thickest here, its mass is about 80% of the total of all the layers of the atmosphere and most of the heat that comes from here is reflected back off the earth’s surface.

The stratosphere is the next layer, it goes to 50km up, and it has the ozone layer in it. Its pressure is 1/1000 of that at sea level.

Next layer is the mesosphere that is 80km up, this is the coldest layer at -100°C and has all the weather balloons in it and is where a lot of the meteoroids burn up because the density of air is just enough to start that happening.

http://en.wikipedia.org/wiki/File:Earth%27s_atmosphere.svg

The fourth layer and final is the thermosphere and the air is so thin that any change in heat is very extreme this why the temperature is very high, it can be 1500°C and goes all the way up to 350km above the earth’s surface. The aurora borealis also occurs in this layer. The exosphere is at the top of this layer. This is where the atmosphere begins to meet the vacuum of space and the international space station orbits here as well