davefoc
Philosopher
Here's a definition of pressure:
Pressure is an expression of force exerted on a surface per unit area.
It's from this site: http://whatis.techtarget.com/definition/pressure
It doesn't use the word container. You seem to believe because you found a definition of pressure that uses the word container a container is necessary for pressure to exist. How does the fact that there is a definition of pressure that doesn't use the word affect your idea about the need for a container for pressure to exist?
Assuming you are serious, I have wondered for awhile if you just don't understand the mechanism by which planets (including earth) prevent their atmospheres from escaping.
This is a link to the Wikipedia article on the atmosphere of the earth:
https://en.wikipedia.org/wiki/Atmosphere_of_Earth
If you go to the section of "Principal Layers" you will see a description of the layers of the atmosphere. One take away from this section is how the atmospheric pressure of earth gradually declines until it is at the pressure of the interplanetary space. You might in particular take a look at the exosphere article. This is the layer thats pressure gradually declines to the pressure of interplanetary space.
It is reasonable to wonder if some gas doesn't escape from exosphere into interplanetary space. Gas molecule speeds are distributed and even if the average speed of the molecules is not large enough to escape earth's gravity some of the molecules near the edge of the exosphere are going fast enough that they do escape the earth's atmosphere so in a sense you're right in that a solid container would be necessary to completely prevent the loss of gas to interplanetary space. However this is a very slow process that is really only significant for the lighter molecules in the atmosphere like helium and hydrogen.
Pressure is an expression of force exerted on a surface per unit area.
It's from this site: http://whatis.techtarget.com/definition/pressure
It doesn't use the word container. You seem to believe because you found a definition of pressure that uses the word container a container is necessary for pressure to exist. How does the fact that there is a definition of pressure that doesn't use the word affect your idea about the need for a container for pressure to exist?
Assuming you are serious, I have wondered for awhile if you just don't understand the mechanism by which planets (including earth) prevent their atmospheres from escaping.
This is a link to the Wikipedia article on the atmosphere of the earth:
https://en.wikipedia.org/wiki/Atmosphere_of_Earth
If you go to the section of "Principal Layers" you will see a description of the layers of the atmosphere. One take away from this section is how the atmospheric pressure of earth gradually declines until it is at the pressure of the interplanetary space. You might in particular take a look at the exosphere article. This is the layer thats pressure gradually declines to the pressure of interplanetary space.
It is reasonable to wonder if some gas doesn't escape from exosphere into interplanetary space. Gas molecule speeds are distributed and even if the average speed of the molecules is not large enough to escape earth's gravity some of the molecules near the edge of the exosphere are going fast enough that they do escape the earth's atmosphere so in a sense you're right in that a solid container would be necessary to completely prevent the loss of gas to interplanetary space. However this is a very slow process that is really only significant for the lighter molecules in the atmosphere like helium and hydrogen.

