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

dusty at sayersnet.com dusty at sayersnet.com
Fri Nov 3 09:25:04 PDT 2017


> ----- Original Message -----
>
> From: "Konrad Gaertner via Dragaera" <dragaera at lists.dragaera.info>
> To: dragaera at lists.dragaera.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
>>
>> 1
>>
>> 2
>>
>> 3
>>
>> 4
>>
>> 5
>>
>> 6
>>
>> 7
>>
>> 8
>>
>> 9
>>
>> 10
>>
>> 11
>>
>> 12
>>
>> 13
>>
>> 14
>>
>> 15
>>
>> 16
>>
>> 17
>>
>
> [snip]
>
>>> to the rotational period of the planet itself. Effectively, it means
>>> this moon must orbit at a point close to (but not exactly at) the
>>> natural altitude for a fully geosynchronous orbit. It cannot diverge
>>> from this orbital period by more than about 2 hours per day (given
>>> Dragaera's 30-hour day), however, or else it would always take fewer
>>> than nine days to appear again in the sky at any particular point on
>>> the
>>> surface of the planet.
>>
>>Is this the only option using normal physics? I'm asking because in
>>another series I'm reading, there's a world with a moon that is similar
>>in size and phases to Earth's, but is only visible every eighth day.
>
> This is the only solution I can see that does not involve the observer
> being at some extremely specific location (such as near one of the poles,
> which does not seem to be the case given the shirtless condition of the
> character in the scene), or some other
> extremely-significant-yet-entirely-unmentioned factor, such as dust clouds
> obscuring the view of the moon, for example. This does not appear to be
> the case here, given the phrasing of the passage.
>
> Regarding how one could have a moon that was visible only once every eight
> days--well, that makes no sense to me using normal physics. There's no
> normal orbit that would cause a body the size of the moon to be visible
> for only one day, then completely missing the next 7. Even with a highly
> elliptical orbit with an 8 day period, an object the size and mass of the
> moon would still have to be pretty clearly visible as a moon on days 7 and
> 9 (and visible at least as a bright star the rest of the time) else, it
> would either have to be moving so fast that there's no way it would be
> able to maintain an orbit, or else it's orbital period would have to be
> much longer than 8 days. (And I hate to think what the impact of tidal
> forces of such an object in such an orbit would be like on the planet's
> surface. Yikes!)
>
> Certainly there could be exotic solutions involving other factors such as
> temporal displacement via wormholes, obfuscation by clouds, or the moon
> getting repeatedly kidnapped by space goblins, but none of these are a
> result of orbital mechanics alone.
>


Maybe it's actually some sort of satellite or space station or other
artificial construct in space that has an artificially unusual orbit.






More information about the Dragaera mailing list