Apply this to a flat earth:

The Earth's atmosphere is a layer of gases surrounding the planet Earth that is retained by the Earth's gravity…

There is no definite boundary between the atmosphere and outer space. It slowly becomes thinner and fades into space

Even assume that this happens on a flat earth—how can it be true without gravity? Why wouldn’t the earth’s atmosphere dissipate into space while the planet keeps moving upward? Inertia MIGHT push a little of the air up with it, but since air is gaseous rather than solid, it would naturally spread out (diffuse) away from the planet or any other specific spot anyway.

citation: http://en.wikipedia.org/wiki/Earth%27s_atmosphere

Try typing "Equivalence principle" into Wikipedia instead.

If that doesn't convince you, then how about this:

If my calculations are correct, then the value of **y** (elevation above sea level) for a given radius to the Ice Wall **r** to have one molecule of the atmoplane (using the atomic mass of nitrogen) in a cylinder of height **h** formed by the Ice Wall with its base at elevation **y** is given by (**y**, **r** and **h** are the *magnitudes* of the measurements in metres, all numerical data given to three significant figures):

**y** = 1.07 * 10^{28} [ 56.7 + ln { π**r**^{2} ( 1 - e^{-9.36 * 10-29h} ) } ]

As you can see, for any finite value of **r**, we can make **h** as large as we like, such that there will always be a value **y** where we will only find a single molecule in that space. Pick any **r** for the radius of the Greater Ice Wall, and pick any **h** such that having a single air molecule in a cylinder of that size would convince you that there is no danger of the atmoplane flowing out into space, plug them into that equation and you will get the necessary height of the Ice Wall for that data.

I admit that at first you had me confused.

I read about the equivalence principle via a lot of different (and unconnected) websites. Here's the thing--the equivalence principle, in any of its three forms, applies to objects that

*fall.* Gases do not fall; their mass is not heavy enough. Otherwise we'd all have to crawl around on the floor to breathe, if we could breathe at all.

I have some things to say about the equation, but please explain it more clearly first. I don't follow from where you derive your variables, or the equation itself, for that matter. For instance, I don't know why you have to use e, ln, or 10 to the negative twenty-ninth power... among other things. Did you get it from a website? If so please include the link.