Re: Dirty Snowball Worlds

On Feb 20, 3:39 am, Tux Wonder-Dog <wes.par...@[EMAIL PROTECTED]
> wrote:
> John Park wrote:
> > Dave Farrance (DaveFarra...@[EMAIL PROTECTED]
) writes:
> >> Logan Kearsley <chronosur...@[EMAIL PROTECTED]
> wrote:
>
> >>>World Idea #1: A tidelocked planet orbiting a red dwarf. The
> >>>temperature goes above freezing at the substellar point, maybe
leading
> >>>to the formation of lakes or a small sea, otherwise just increased
> >>>sublimation that keeps it relatively ice free. Question- do glaciers
> >>>across the hemisphere creep towards the substellar point, or would it
> >>>be more likely that the whole above-freezing region would remain ice-
> >>>free, with mostly-static icesheets thickening as you get further
away?
> >>>Or something else entirely?
> >>>Over on the dark side, temperatures get too cold even for the natives
> >>>to find comfortable but there's no sunlight anyway, so it doesn't
much
> >>>matter. Perhaps there's a CO2 icecap around the antistellar point?
>
> >> I don't know enough about planet formation to comment on World Idea
#2,
> >> but the problem with the above idea is that it will get *very* cold
on
> >> the darkside.  The entire atmosphere except for any helium would
freeze
> >> out.  The water would also eventually find its way around to the
darkside
> >> via sublimation.
>
> > Wouldn't that depend a bit on how thick the atmosphere was and how
> > efficient its wind system was in moving energy around? (As far as I
know,
> > despite its slow rotation--and because of its thick atmosphere--Venus
has
> > no significant temperature difference between its day and night
sides.)
>
> It very much depends on the atmosphere's density and its composition.
>
> You would have a "hot spot" which would shift with libration
(precession? as
> well?).  This would create at least one atmospheric cell - in the form
of a
> static cyclone.

I have never had this adequately explained- some of the simulations
result in two cyclones, mirrored across the equator, and others result
in a single cyclone. In the single cyclone case, what determines the
direction of rotation?
And what happens when the planet's rotational period is significantly
longer than 24 hours?

-l.