Aviation and Aerodynamics for Schools
Initiative Aviation Base Hamburg: Education

Informations about the Atmosphere

last updated 09/05/2013

   
The atmosphere of our earth does not reach very far into space. From an orbit you see it very distinct just before dawn as a blue stripe above the horizon. Click onto the image to load a hires image of this last Space Shuttle mission (source: NASA 2011).
You load a short movie of this here: sunrise_shuttle.mov (source: NASA 2011)
This image shows a hurricane. But you can see the atmosphere very nicely. (source: NASA). Click onto the image to load a hires image. Closest to Earth’s surface, the orange-red glow reveals the troposphere—the lowest, densest layer of atmosphere, and the one we live within. A brown transitional layer marks the upper edge of the troposphere, known as the tropopause. A milky white and gray layer rests above that, likely a slice of the stratosphere with perhaps some noctilucent clouds in the mix. The upper reaches of the atmosphere—the mesosphere, thermosphere, and exosphere—fade from shades of blue to the blackness of space.
(source: NASA 2011)
   
     

ISS crosses the Carribean, the US, and the north pole. Load films here, too! Source: NASA 1/2012
Hires Image,
Film 14MB (Quicktime), Film hires 96MB

Moonset over South America, filmed from the ISS (shows the thickness of the atmosphere).
Source: NASA 2013
Film web, Film hires

     

 

The standard data of the atmosphere (US standard atmosphere) are:

Pressure p = 101325 Pa = 760 mm Hg

Temperature T = 288.15 K = 15°C

Density rho = 1.225 kg/m3 = 0.001225 g/cm3

Molar Mass M = 28.964 g/mol

 

Composition of Air in %

Nitrogen N2 78.084
Oxigen O2 20.9476
Argon Ar 00.934
Carbon Dioxide CO2 00.0314
Neon Ne 00.001818
Helium He 00.000524
Krypton Kr 00.000114
Methane (Natural Gas) CH4 00.0000087
Hydrogen H2 00.00005

 

 


 

Velocity of Sound in Air depending on Moisture at 20°C (68°F)

344 m/s (343.477 – 344.742 m/s)

1238,4 km/h (1236.52 – 1241.07 km/h)
769.5 mph (768.338 – 771.165 mph)

 

For dry air as a an ideal gas:

T in °C      T in °F       v in m/s      v in km/h v in mph

-100

-148

263.5

948.6

589.4

-50

-58

299.5

1078.2

670.0

20

68

343.4

1236.24

768.2

40

104

354.8

1277.28

793.7

80

176

376.7

1356.12

842.7

Differences in pressure almost do not play any role for the speed of sound.


 

Viscosity of Air

Temperature and   Viscosity in 10-5 poise (µPas)

K
°C
°F
µPas
100
-173
-279.67
7.1
200
-73
-99.67
13.3
300
27
80.33
18.6
400
127
260.33
23.1
500
227
440.33
27.1
600
327
620.33
30.8