[Dragaera] Dragaera and Moons **Minor Vallista Spoiler, nothing plot related**

[Jon]

On 11/6/2017 8:51 PM, Jerry Friedman wrote:
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> ------------------------------------------------------------------------
> *From:* Jon Lincicum <lincicum at comcast.net>
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> >       From: Scott Schultz via Dragaera <dragaera at lists.dragaera.info>
> >
> >> -----Original Message-----
> >> From: Dragaera [mailto:dragaera-bounces at lists.dragaera.info] On Behalf
> >> Of
> >> Jerry Friedman via Dragaera
> >> Sent: Saturday, November 04, 2017 1:47 PM
> >> To: dragaera at lists.dragaera.info
> >> Subject: Re: [Dragaera] Dragaera and Moons **Minor Vallista Spoiler,
> >> nothing plot related**
> >> Sent from my iPhone please excuse typos
> >> > ----- Original Message -----
> >> >
> >> > From: "Konrad Gaertner via Dragaera" <dragaera at lists.dragaera.info>
> >> > To: dragaera at lists. To.info
> >> > Sent: Friday, November 3, 2017 5:04:29 AM
> >> > Subject: Re: [Dragaera] Dragaera and Moons **Minor Vallista Spoiler,
> >> > nothing plot related**
> >> >
> >> >> On 11/2/2017 10:19 PM, Jon via Dragaera wrote:
> >> >> Spoiler Space
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> >> > [snip]
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> I understood Scott to be suggesting that Littlemoon was in a 
> synchronous orbit close to the eastern or western horizon from where 
> Dolivar lived, so slight changes in Dragaera's rotation (or 
> Littlemoon's orbit?) would bring it it slightly above and slightly 
> below that horizon.  I still have trouble imagining it, though.

Well, yes, I suppose it's possible if the moon were exactly 
geosynchronous, but not exactly along the equator, then the apparent 
"path" it carves out in the sky might cause it (from some locations on 
the terminator line of visibility of the moon) to "rise" and "set"--but 
in such a case it would basically pop up very briefly, then "set" again 
within a day or two, and always remain very close to the horizon.

But in such a case, it wouldn't take a terribly long journey east or 
west to reach a point on the planet where either it was always visible, 
or always hidden. I have trouble reconciling that situation with the way 
Dolivar talks about it.

>
> It's still a big coincidence.  And from what I've been reading today, 
> our geostationary satellites have to use onboard thrusters to stay in 
> their orbits--"station keeping".

True. But that's due mostly to tidal forces caused by the orbit of our 
own Moon. It's entirely possible that "Bigmoon" and "Littlemoon" could 
have an established orbital resonance that keeps Littlemoon in place, 
naturally.


Majikjon

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