ATMOSPHERE

The [Earth|Earth's] atmosphere surrounds the [planet]. It is a thin, clear, yet heavy [ocean] of [air] above our heads. It weighs down about 3 kg/cm². The atmosphere also protects the Earth. [Comet|Comets], [meteorite|meteorites], [dust], and other things burn up due to [friction] in the [mesosphere]. The atmosphere also keeps the Earth [warm], acting like a blanket, due to the [greenhouse effect].

When the Earth was forming it lost a lot of [heat] and [volcanic gasses]. Some of these gasses were kept close to the [Earth] by [gravity]. The [composition] of the atmosphere is as follows:

  [Nitrogen]: 78%
  [Oxygen]: 21%
  [Argon]: 0.93%
  [Water Vapor]: 0-4%
  [Other Traces]: ?%
  [Carbon Dioxide]: 0.03%

The above are give/take figures. The atmospheric composition is not exact. The sky will not fall if there is 79% nitrogen instead of 78%.

Earth's atmosphere is made of many [layers]. They are as follows:

[Troposphere]:
  closest layer to Earth
  contains [weather]/[clouds]/[smog]/75% of all of Earth's gasses/[dust]/[ice]/[water]



[Stratosphere]:
  little [temperature variation] through stratosphere
  converts [oxygen] into [ozone]
      [Ozone] protects us from [UV rays]



[Mesosphere]:
  melts [meteor|meteors]/[space dust]



[Thermosphere]:
  contains [ionosphere]
      [ionosphere] reflects [radio waves] at night/[absorbs] them during the day



[Exosphere]:
  [H] and [He] molecules escape from the exosphere into [outer space]
  exosphere is [The Edge]
  there is no fine [distinction] between the end of the exosphere and the start of space

Well, that's pretty much it for the [atmosphere].

atmosphere (thing)