My guess is that the atmosphere is not sucked in by the vacuum of the space because, the pressure gets lower the higher you go and is zero at the point of touching the space. There has to be less and less air particles as one moves upward. Getting to the point where there is only a layer of one particle. If the atmosphere is 100 km thick and the Earth's radius is 6370km, then the 100km wide atmosphere is only 1.5698587 % thicker at the sea level than at the end of the atmosphere! If the distribution of air molecules was the same! No wonder why at 10 000m above the sea level the pressure change hits your ears only slightly more than going downhill on Earth. The distribution of the air molecules can be calculated by taking into account the air resistance. It's about .16 m/s2 (ever wondered why the earthly acceleration isn't exactly 10 m/s2 but 9.84 m/s2?). Hence, 0.16 out of 10 is 1.6260162 %. The difference is an unbelievable and shocking 0.0561575 % or simply 0.05 %. Thats makes 1 in 2000 deviation. When taking into consideration relative error, I infer that the distribution of air molecules in the atmosphere is even! Hence the atmospheric pressure can be calculated because at 10 000m above sea level the pressure will be 10 % lesser than at the sea level.

PAWEL KOLASA