Logan Kearsley wrote:
> On Feb 21, 4:22 am, Tux Wonder-Dog <wes.par...@[EMAIL PROTECTED]
> wrote:
>> Logan Kearsley wrote:
>> > 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?
>>
>> I think it would be the libration that would determine the direction of
>> rotation. It'd be heating an area that would shift within a few degree
>> per orbit, and the effect would be the same as swinging a stone on the
>> end of a string.
>
> As far as I can tell, libration wasn't included in the simulations.
>
>> Could someone who knows a bit more than I do, explain the two cyclone
>> concept? The only reason I can think of why there would be two
cyclones
>> is that there is still more rotation in the system than should be in a
>> tide-locked planet. And thus there is still a north/south-hemisphere
>> atmosphere ...
>
> How much 'should' there be? It is what it is. I suspect that's a large
> part of what's happening.
> Or, an alternate explanation might be that I'm horribly
> misinterpreting the graphs. I don't *think* I am, but I'll throw it
> out there as a possibility, 'cuz the article never actually mentions
> cyclones; one must infer them from the temperature and pressure plots.
I've read the article. I think I made an error - I had assumed that the
atmospheric circulation would be centred around the hot spot and otherwise
had become static, whereas they had worked on a different assumption -
that atmospheric circulation would be directional as in the Earth's
atmosphere, eg, east-to-west and vice-versa, north-to-south and
vice-versa,
and that the hot spot wouldn't override directional circulation.
That said, the atmosphere is divided into two cells based on hemisphere;
that's basic. I didn't see two cyclones, though - it looked like a
simplified version of the Earth's atmosphere.
Wesley Parish
>
<snip>
>
> -l.
|
