# Earths Atmosphere

tlcw | 14:59 Thu 28th Dec 2006 | Science
How many miles up from the Earths surface is its atmosphere end?! Thanks!

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According to wikipedia....

There is no clear boundary between the Earth's atmosphere and space as the density of the atmosphere gradually decreases as the altitude increases. Nevertheless, the Federation Aeronautique Internationale has established the K�rm�n line at an altitude of 100 km (62 miles) as a working definition for the boundary between atmosphere and space. This is used because, as Karman calculated, above an altitude of roughly 100 km, a vehicle would have to travel faster than orbital velocity in order to derive sufficient aerodynamic lift from the atmosphere to support itself. The United States designates people who travel above an altitude of 80 km (50 statute miles) as astronauts. During re-entry, 120 km (75 miles) marks the boundary where atmospheric drag becomes noticeable.
what altitude is it possible to brethe up to, at 10,000 feet you can become hypoxic, but you are still alive.
a lot
If this is a parent asking on behalf of a child, then I reccomment Physics on the back of an envelope Clifford Scwartz.
see Amazon , and see his page 104

ON constant density, P = rho times g times h

If you dont understand this, give up now.

with p a const, you get an answer of 5 mi

far too little

so make p a variable - and the simplest is linear,
then the calculation involves integration,
and you get ( a familiar) exponential relation.

and around 12 I think.

Anyway I enjoyed the book

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kobi

rkp52

Jahulaye

Moil

ellietal