Atmospheric mixing on walnut earth

Suppose we had an Earth-like planet based on Saturn's moon Iapetus. Iapetus has an equatorial ridge, 13 km high, which runs around it. Scaling that up to an Earth-sized planet, it would have a ridge almost 120 km tall. (Handwaving things like hydrostatic equilibrium aside for now; it doesn't matter how the ridge formed, it's just there.)

Given that 120 km is over the line of "space", the two sides of the planet would be effectively cut off from each other. I know there's some air above that line, because the International Space Station has drag, but if the two sides of the planet had vastly different atmospheres (say, one half has a nitrogen-based atmosphere like Earth, while the other has a carbon-dioxide-based one like Venus), would that be stable for reasonably long timescales or would they just diffuse over the top?

posted almost 6 years ago

Skyler‭

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