Query for Dr. Ganymeade

[mad13142000]

So, I just got done reading John Barnes' book 'Earth Made of Glass'...
It posits an interesting world...
Briand
circling an F star, it is a borderline Greenhouse world...

..an intermediate case between Venus and Earth, with 7 atmospheres of pressure above dense salt-saturated seas...very active plate techtonics (with many more and smaller plates than Earth)...a madly active atmosphere constantly rolled and burned as local concentrations of reducing and oxidizing gasses ran into each other at high temperature and pressures; the results dropped into the seas, keeping them forever a saturated cauldron of more exotic material than anyone could catalog...
Near its South Pole, volcanic hotspots...blasted up...forming a few imense plateaus - really islands in the sky- that reached 12 km above average surface altitude, well up into Briand's stratosphere...gravity 1.3 standard...

The civilization lives on these plateaus that have been terraformed to keep a 'bubble' of oxygen rich air centered in the polar high...But assuming that native life could and would mimic the same effect...
Surely the IISS would label the planet an Exotic or Dense, High Atmosphere, and probably wouldn't ever catagorize it as a habitable planet...
I liked the description he gives (especially the fight against the blinding, Actinic glare the star gives off, and the bizzare features of the atmosphere (including large clouds of flammable gas reaching into oxygen layers and then lighting up)) But I wonder if it would maybe give some ideas on how a planet labeled X could be viewed as being able to have life, even if in a small area (total area habitable on this planet was only 550,000 sq. km)...no domes, no filters, but they live on a planet that would kill in less than a second if they were anyplace other than their small 'home'...
Just a thought
-MADDog

 

[Straybow]

Two problems. First the stratosphere is, by definition, above the troposphere. A polar high, or any other adiabatic weather effect, is by definition confined to the troposphere. Some other means would be needed to block whatever wind patterns exist in the stratosphere of such a planet.

Because of diffusion effects it would be impossible to keep toxic chemicals out of the "bubble" without a literal bubble. Too many molecules could have nasty effects on health and agriculture in the ppm range. Carbon monoxide is deadly at 50 ppm in ~24 hrs.

To guage the diffusion effect, CFCs are such heavy molecules that they should settle to ground level. Winds can only carry them up 9-15 km, where the troposphere ends. Yet CFC molecules migrate by diffusion to the ozone layer, being detected in samples taken 5-6 km above the troposphere in the polar regions.

Domes would be the only possible way to isolate an N2/O2 bubble for a human colony.