An interesting pressure proof

The engineer ought to know this one as well as I...I'm trying to remember the theorem, and I'll find it in my book if I look hard enough.  There's a rule we use: pressure distributions are even only on a sphere, sort of as a rule of thumb.  What is meant by that is say, in the case of a pressurized aircraft, the forces on the skin (from the inside being pressurized) are only equal in the case of a sphere.  In all other situations we have to re-enforce and mold shapes to minimize the variances....I'll find it this weekend.

I never said the forces on the inside of the dome would be equal. I said the pressures at ground level would be, and I still think I'm right, regardless of any engineering rules of thumb you may have. There's no force to account for pressure differences at different points at the same elevation, so the pressure must be constant. I think the engineering principle must not apply in this case, or else applies in some way other than the way you think it does.

Perhaps beyond the 150' ice wall which contains the oceans there is a higher wall of ice or rock which contains the atmosphere

... but wasnt the guards guarding the worlds edge? what behind the edge? more earth?

Sorry jadexg, not quite sure if I follow.  If I am correct in what you are referring to, it is that the stress equal only in a sphere, not exactly the pressure.  There are stress concentrations at corners, making them weak points in a container.  That is why filets and radii are added to corners to round them out.  

However, I would say that the pressure inside a compressed O2 cylinder would be just about equal everywhere, whether in the middle or at a corner (at the same level, of course).

Sorry jadexg, not quite sure if I follow.  If I am correct in what you are referring to, it is that the stress equal only in a sphere, not exactly the pressure.  There are stress concentrations at corners, making them weak points in a container.  That is why filets and radii are added to corners to round them out.  

However, I would say that the pressure inside a compressed O2 cylinder would be just about equal everywhere, whether in the middle or at a corner (at the same level, of course).

there's a differance though, being that the O2 is compressed. the air on earth isn't compressed the greatest portion of the air around us in nothing.

Uh, ok.  Then the pressure in an open baseball stadium would be the same in the middle of the field as it is in the corner of the dugout (again at the same level).

The explanation I seem to remember hearing from somebody, to explain that the pressure near the rim would be lower than near the middle, was supposed to apply to the case where a dome enclosed the Earth and thus the air column above an observer near the rim would be much shorter than the air column in the middle.

However, this doesn't mean the pressure would be less: as skeptical scientist mentioned, if the pressure there were less, then the air in the middle would press outwards until the pressure were equalized at any given altitude.

Just imagine a conical basin filled with water.  The pressure will, as always, only be a function of depth: if somehow the pressure in the lower corner decreased, the rest of  the water would sink and repressurize the water in the corner.

So you're saying that the earth is basically a giant snowglobe?

Sweet..