The layers of the atmosphere are divided by their temp. The first layer (Troposphere) is the warmest at the bottom and then it gets colder as you go up. The Stratosphere starts out cold and then it gets warmer as you go up. After that comes the Mesosphere, it starts out warm and then gets colder as you up just like the Troposphere. Last but not least is the Thermosphere, the first part is cold and then it gets hotter. The Thermosphere is the hottest layer (2,730 degrees F) according to thermometer. We would not feel the heat though, so to us and our bodies we would feel like we were freezing.
The greenhouse effect is something many people know about but they know very little about. What it is, is the suns rays come down and hits the earth and the earth absorbs the heat and on the way and on the way in the atmosphere absorbs some of the heat. Then the heat from the earth when the ground gets colder it bounces against the atmosphere and back on to the ground and the ground absorbs some and bounces the rest back to the atmosphere.
The gasses in the atmosphere are mainly nitrogen and oxygen, there are however a few very little amount of other gasses. The chart shows the other gasses, though Argon is not always considered alone, most of the time it is considered with the other gasses. (Carbon Dioxide, Methane, Nitrogen oxide, and water vapor) These gasses are in balance, they give us the air we need to breathe, if they were off balance they would be breathable.
Without the atmosphere protecting us from the suns radiation heat we would all die of overheating. Though be cause we are polluting the earth the Ozone layer (the one that protects us the most) has been getting holes in it so its not protecting us as well as it used to.
The atmosphere even though we may not know it is right around us right now, we are in the Troposphere, even right to the ground we are in the atmosphere. The Troposphere is where planes fly and clouds are at, this is where weather happens, the clouds can't go any higher than the Troposphere.
The Thermosphere is where the satellites fly. There has been many discussions on where the thermosphere has ended but everyone has a different idea.
The pressure is the greatest where we live. When we go higher in the atmosphere it gets less.
The mesposphere is what protects us from meadiors. Also astroids