[Dragaera] Fwd: Moon(s) and Tides (was Re: Jhegaala etc.)

[Ken Koester]

Rebecca Harbison wrote:

>
> On Jul 18, 2008, at 11:18 AM, Jon Lincicum wrote:
>
>> Matthew Jennings wrote:
>>
>>> Conspicious by its absence: a moon.  Is the Dragaeran 'planet'  
>>> moonless? Did
>>> we already know this. Would have been handy for Vlad.
>>>
>> In /Phoenix/, Vlad talks about the winds and tides when going to  
>> Greenare. Tides means moon. QED.
>>
>> It is somewhat curious that we do not see mention of it. But then,  
>> perhaps it is a much smaller moon, or it was a new moon during the  
>> two or three days he's in town stirring up trouble before he's...  
>> inconvenienced, and not in a position to notice anymore.  
>> Alternatively, perhaps the moon is composed of dark matter and not  
>> visible at all?
>
>
> The Sun (at least on Earth), also produces tides -- they make up  
> about a third of the strength of the total tide on Earth.  Assuming  
> normal gravity, if a planet orbited a sunlike star and had no  
> satellite, the tides would be weaker than Earth's, and happen at  
> about the same time every day (high tide around midday and midnight,  
> low tide around dawn and dusk), but they would be present.  They also  
> would be nearly constant in strength at the same location -- local  
> places might have stronger effects depending on the shape of the sea  
> bottom (as, I'm sure, any sailor could tell), but there wouldn't be a  
> strong spring tide and a weak neap tide over the month.
>
Depends on how close it orbits the primary as to how strong or weak it 
might be, but given "sunlike", yeah, probably weaker, but perhaps not as 
weak as Earth's solar tides.  There might be a sort of hysteresis effect 
making the tides lag beyond the times you specifiy, base on the shape of 
the coast, offshore land masses, channels, etc.  The sea bottom itself 
wouldn't be as influential as the shape of the coast; the bottom off 
Savannah is much the same as anywhere up to massachusetts, yet Savannah 
has the highest tides south of Maine, solely because it sits in the 
middle of a deep indentation.  also, the orbit is unlikely to be 
perfectly circular, so you would get seasonally stronger/weaker tides, 
similar to spring & neap tides (but not as frequent).

Snarkhunter