Re: Multiple thalassogens


Logan Kearsley wrote:
> <chornedsnorkack@xxxxxxxxxxxx> wrote in message
> news:1132851832.446546.240030@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> <snip>
> > > > > > > > > But what about an ocean of SO2 floating on an ocean of CO2,
> > > > > > > >
> > > > > > > > Dubious. Liquid SO2 is miscible with a plenty of organic solvents, I
> > > > > > > > suspect with CO2 as well.
> > > > > > >
> > > > > > > Hm. I find that odd, as SO2 is polar and CO2 is not.
> > > > > >
> > > > > > The difference is there, but not that huge.
> > > > >
> > > > > Almost as big as it is with water. CO2 is completely non-polar, while SO2
> > > > > has a dipole moment of 1.63 D- less than water at 1.85 D, but still higher
> > > > > than ammonia at 1.47 D.
> > > > >
> > > > Comparing water and SO2, wou will notice that SO2 has a molecular mass
> > > > of 64 and water has 18, yet SO2 boils at -10 Celsius and water at +100.
> > > > The difference is that water can form hydrogen bonds and SO2 cannot,
> > > > lacking available H.
> > >
> > > True. That brings up the possibility of another thallasogen: H2SO4, which
> > > has a much wider liquid range than water.
> > > I assume H2SO4 would remain highly corrosive even when not in solution with
> > > water,
> >
> > I assume that especially when not in solution...
> >
> > > but would it be possible for it to coexist with a CO2 ocean?
> >
> > I suppose so. Depending on what the bottom is, though.
>
> Seems to me that that's not so much an issue of coesxisting with CO2 as it
> is an issue of existing at all.
>
True.

> > Venus now has clouds of around 75% H2SO4 - the concentration ought to
> > vary, perhaps someone can comment. The acid rains constantly down, but
> > evaporates in hot lower atmosphere without reaching the surface. The
> > vapour somehow returns back up and condenses.
> >
> > Venus also has 90 atm CO2. But the lower levels are hot.
> >
> > If Venus were cooled appreciably then one would expect the sulphuric
> > acid rain to get further down. If the temperature were low enough, or
> > if the total quantity of available sulphuric acid were increased, the
> > acid might reach the surface. Then it depends on whether there are
> > available bases or if those are exhausted. In the latter case, Venus
> > might end up with lakes and oceans, and rivers and springs, of strong
> > sulphuric acid.
>
> I'm sceptical of sulphuric acid oceans on Venus. I don't think there's
> enough in the clouds to make a whole ocean out of. But lakes and rivers,
> yes, and on a planet with much more surface sulphur, then oceans.
>
> > Also when the temperature of Venus' atmosphere at the 73 atmosphere
> > level reached 31 Celsius, the carbon dioxide would form a surface of an
> > ocean. I expect that while small amounts of sulphuric acid can dissolve
> > in carbon dioxide, and small amounts would evaporate into the overlying
> > gas phase, sulphuric acid would not be freely miscible and would sink
> > to the bottom of carbon dioxide.
> >
> > You can have clouds on both sides of the ocean surface, as
> > precipitation of liquid sulphuric acid can happen both in gaseous and
> > liquid carbon dioxide, but the density and viscosity of the surrounding
> > carbon dioxide, as well as surface tension of sulphuric acid, changes
> > discontinuously on the surface of carbon dioxide... And of course, you
> > can have critical opalescence. I wonder what precisely happens to swell
> > that reaches critical point...
>
> Oo! Clouds of one thallasogen inside the liquid layer of another is a cool
> thought. I assume the same thing could happen with water?

As in, clouds of water? Yes. Actually, if you have enough carbon
dioxide, water could be sandwiched as an ocean - or as discontinuous
layer.

As in, clouds of something else in water... you would want a
thalassogen with appreciable vapour pressure as well as limited
solubility in water

> Swell that reaches the critical point would probably just vaporize
> (supercritical fluidize?) I'm not quite sure how to visualize that, though.
> Maybe waves just never get above a certain height because the tops evaporate
> off. That would be a very finely-tuned situation, though, and further
> cooling would leave us with a regular liquid/gas interface, whose appearance
> we know well.
>
Not quite.

The critical point of carbon dioxide is 73 atmospheres and 31 degrees
Celsius.

At 0 Celsius, the vapour pressure of liquid carbon dioxide is 34
atmospheres. At the triple point, -56 Celsius, it still is over 5
atmospheres.

This means that liquid-gas interphase of a carbon dioxide ocean has a
rather low contrast between the density of gas and the density of
liquid already at the triple point. Carbon dioxide would also have low
viscosity compared to water, low viscosity contrast between liquid and
vapour, and low interface tension. The contrasts would decrease as the
temperature climbs closer to 31 Celsius.

<snip>

> > Incidentally, a fluid with excellent intrinsic stability is HF...
>
> Which also happens to have an inconveniently low cosmic abundance.
> Otherwise, I'd be designing creatures living in HF solvent using NH3 as an
> oxidizer and CF4 as a carbon source.
>
> <snip>
> > > > > Stephen Gillett's suggestion for how to get a world with
> > > > > SO2 oceans starts out similar to that, and has most of the water get
> > > > > dissociated, with the hydrogen lost to space, leaving behind loads of free
> > > > > oxygen to react with the sulphur.
> > > > > The hydrogen originates, I presume, from hot sulphur reacting with water
> > > > > vapor to form sulphur oxides?
> > > > Yep. Perhaps over the intermediate H2S. And as above, double-checking
> > > > there would probably be not much hydrogen.
> > > >
> > > > Naturally, lakes of brimstone would have to be hotter than on Earth -
> > > > +119 Celsius minimum. They can coexist with water if there is an
> > > > elevated pressure. The heat may come from the sunlight or else from
> > > > internal heat.
> > >
> > > Something Venus-ish, perhaps, with a thick (compared to ours, anyway)
> > > atmosphere of carbon dioxide causing an enormous greenhouse effect (but not
> > > nearly so enormous as Venus's- just enough to keep the average temperature
> > > above 100C). A thicker atmosphere means more even heat-distribution, though,
> > > which could make the idea of frozen sulphur at the poles a problem. Might
> > > just have to put it closer to its sun.
> > >
> > Well, Venus additionally has slow rotation - and therefore limited
> > Coriolis forces.
>
> This is true, but a thicker atmosphere means more even heat distribution
> regardless.
> Maybe we could actually do without lots of CO2 in this case, as water vapor
> is already a more effective greenhouse gas, and if the water is boiling off
> at the equator, there's going to be lots of it in the atmosphere.
> Actually, that might be a problem with the water boiling off at the equator-
> the extra vapor in the atmosphere will increase the pressure until no more
> evaporates, and since the pressure will be fairly evenly distributed over
> the whole globe, that means either no liquid water or liquid water
> everywhere.
>
You could have unsaturated water vapour atmosphere in the tropics, and
a saturated one in the polar regions. The mechanics would also be
simplified by presence of an inert permanent gas - but Mars does not
need one.
> -l.
> ------------------------------------
> My inbox is a sacred shrine, none shall enter that are not worthy.

.

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