P E E L I N G B A C K T H E L AY E R S O F

T H E AT M O S P H E R E

EARTH’S ATMOSPHERE• Earth's atmosphere is our natural shield against the harsh

conditions of space— including everything from meteors and falling

satellites to deadly ultraviolet radiation from the sun.

• Air It also contains the air we breathe, the weather we experience

and helps to regulate planetary temperatures.

AIR

• The atmosphere consists of layers of gases, called "air", that

surround the planet and are retained by Earth's gravity.

• "Air" is the common name given to the combination of gases used

by organisms for breathing and photosynthesis.

• By volume, dry air contains:

– 78.09% nitrogen

– 20.95% oxygen

– 0.93% argon

– 0.039% carbon dioxide

– Smaller amounts of various other gases and water vapor

ATMOSPHERIC LAYERS

Air composition and atmospheric pressure is not consistent

throughout the atmosphere, however, and varies at different

altitudes, giving the atmosphere 5 distinct principle layers.

TROPOSPHERE

• Beginning at the surface of Earth, the troposphere extends to around 7 miles

up.

• This is the layer we live in and contains most of what we consider to be "the

atmosphere", including the air we breathe and nearly all of the weather and

clouds we see.

• In the troposphere, the temperature of the air decreases the higher you go.

STRATOSPHERE

• This layer exists between 7 to 31 miles above the surface of Earth.

• Unlike the troposphere below, the air temperature actually increases with

altitude making the air stratified.

• When possible, commercial jet aircraft fly in the lower stratosphere to avoid

the turbulence which is common in the troposphere, due to convection.

MESOSPHERE

• The third layer of Earth's atmosphere, the mesosphere extends from around

31 to 50 miles high.

• Considered one of the coldest places on Earth, the average temperature is

around -120°F.

• This layer is where most meteors burn up upon entering Earth's atmosphere

and is the highest elevation at which a cloud can form.

THERMOSPHERE• Spans the area 50 to 440 miles above Earth's surface.

• Where high energy ultraviolet and x-ray radiation begin to be absorbed causing massive

temperature variations. Highly dependent on solar activity, temperatures here can range from

as low as -184°F to as high as 3,630°F.

• Despite the high temperatures, this layer of the atmosphere would still feel very cold to our

skin due to the very thin atmosphere. There is not enough molecules to transfer heat.

• Earth's curvature becomes distinctly clear and space travelers begin to

experience "weightlessness".

• Because of the heavily ionized atmosphere present in the thermosphere, it is also home to the

phenomenon known as auroras.

EXOSPHERE• The final layer of Earth's atmosphere.

• This layer extends from around 440 miles above Earth to nearly 6,200 miles.

• The atmosphere in the exosphere is incredibly thin and no longer behaves like normal gas.

• The atoms and molecules are so far apart that they can travel hundreds of miles without

colliding with one and another.

• This layer contains a large portion of low-Earth orbiting satellites.