----- Original Message -----
From: Robert A. Howard
Subject: GM: Re: Re: A new calender
> From: "Doc"
> Gods, now THAT'S a can of worms. So much for the latest dormant stage.
>
> The calendar is going to depend upon Lots-O-Things. Is it solar (like
the
> Gregorian calendar currently in use) or lunar (like the Islamic or
Chinese)?
> Or is it some crossbreed (the Mayan calendar, which I won't even BEGIN to
go
> into)? Or something else entirely?
> end quote:
>
> It's seasonal. There are 4 seasons to the year (Spring, Summer, Fall and
> Winter). However, it is not a solar year. The planet in question is a moon
> of a Jupiter-style planet with rings (okay, about 10x bigger than Jupiter,
> but still *grin*). I'm not sure how long the orbital period is around the
> brown dwarf (basically it is about the visual size of our own moon, as I
> believe the gravitational influences would then be about the same as
Luna).
> The brown dwarf star, in turn, orbits a green star, far enough out that
it's
> in the coldish part for allowing water (more ice than water). It's the
brown
> dwarf's own additional heat output and the gravitational influences that
> keep the water liquid. :)
>
Of _course_ you can't keep things simple. As long as I've been
kicking around here, you'd think I'd remember...
Alright. You have a moon of a brown dwarf, itself in orbit around a star.
(A green one! Clearly not limiting yourself to the usual types...) Now
THAT'S ugly. To be far enough from the BD for it to appear the size you're
talking, it's pretty far out from the primary. Assuming the BD is supplying
a good amount of heat, you can get away with putting the thing out past the
equivalent of Mars' orbit; objects with enough heat to create their own
habitable zones do wonders for placement flexibility...
Plus, you probably need a brighter star than Sol in order to get a similar
amount of light at that range. The fact that you have a green tint to the
light makes things more interesting, but I'm digressing VERY far right now.
(Or maybe the sun just _looks_ green...hmm...)
> As you can see, it's a bit harder to just have a traditional solar
calendar
> or such. ;) But I figure an planetary wobble (of the axis) of about 1 year
> would allow for proper "seasons". :) And if the brown dwarf was in a
mostly
> circular orbit, then there'd not be much variation of year-to-year
weather.
>
Not quite. You're on target on the axial tilt, since that's what causes
seasons on Earth, but the distance from game world to the star is going to
vary depending on where you are in orbit around the dwarf star. Overall it
probably isn't going to cause too much difference, since the bulk of the
heat is coming from the dwarf instead of the star.
> But it's mostly just window dressing. There are still 4 seasons, and the
> year is based on that. I'm sure there are astrological calendars as well,
> but as I'm not sure on the exact orbital length of the brown dwarf, that
> doesn't matter for now.
Despite the wonky physics of the setup (but hey, this ain't Traveller), you
shouldn't have too much of a problem. You might want to look at the
possibility of "Grand Seasons" from the fact that you technically have two
heat sources, but that's more climate than a practical matter of calendar
cycles. (Though it could also make for an interesting point of long-term
timekeeping, perhaps taking the place of centuries or such. Certainly the
elves would be aware of it, and would certainly take it into account...)
One last side note: Unless the orbits are seriously out of the plane of the
ecliptic, you're going to have VERY regular eclipses. Think on that when
you're setting up your calendar--an event that regular and spectacular will
certainly play a role in defining years, and probably gets marked by a major
holy day in most religions...
---Doc---
GURPS fan - GMAST-L Old One (once banished)
Philosopher - Alternate Historian - General Crank
email: bravado@mindspring.com
web: http://www.mindspring.com//~bravado
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