I read about the experiment of Magdeburg hemispheres [1], where they attached two halves of a sphere only by emptying the sphere from air, and they couldn't pull them apart using 16 horses!
So why doesn't the vacuum in outer space absorb the Earth's atmosphere if it's that powerful?
The obvious answer would be gravity, but how?
I mean, gravity isn't as strong as 16 horses, right?
Space isn't a vacuum. It is filled with ultra low pressure hydrogen.
If you did that vacuum sphere experiment in space, it wouldn't take 16 horses to pull it apart. The force that held the halves of the sphere together was the weight of the displaced atmosphere.
Consider the state of the sphere halves before the inside was emptied. The pressure on the inside and outside was about 14 pounds per square inch. After it is only 14 PSI on the outside and 0 PSI on the inside thus the two halves of the sphere are being held together by that 14 PSI of atmospheric pressure. If you were to take this sphere into space. The pressure holding it together would reduce and it would easily separate.
Gravity is what holds an atmosphere to a planet. But it was the weight of that atmosphere which held the sphere halves together.
