Wesnoth calendar

[Simons Mith]

Actually, I suppose a much more fundamental question to answer first is - are we going to have an Earth-style solar system, rather than a more magical world like, say, the Glorantha of the RuneQuest RPG setting?

[esr]

Speaking as the current Mr. Continuity Guy, I say we go with a more SFnal approach - actually model the solar system and try to be consistent. This will be important for works-in-progress like Thunderstone that will be more SFnal in flavor (with space travel as part of the background).

One thing I can contribute is my belief that Irdya has two moons: A Greater Moon somewhat like our Luna and a Lesser Moon that is much smaller and in a closer orbit - doesn't resolve to a sphere with the naked eye. When Wesnothians say "the Moon", they mean the Greater Moon. (I think the Lesser Moon may be a captured asteroid, not even spherical. Like Phobos.)

I like Simons Mith's calendrical suggestions. He's thinking about the right things.

Aetheryn and I have been thinking about calendars from a different angle. We've had to work out some details of the Elvish calendar and its relationship to the Wesnothian one. Here's what we know:

The Elvish calendar is in years since the Compact of Harmony, Karas Erenthi or KE in Elvish. The Compact of Harmony ended the Elvish tribal wars, 1 YW is sometime in the 6th millennium KE, I think we set it at 6751KE. Scholars of other civilzations not infrequently use Elvish dates as a sort of common long-count.

Both human and elvish years begin on the vernal equinox. Human months are solar and fixed relative to start of year. Elven months are true lunar cycles and precess relative to the solar year; Elves don't use months much, preferring to reckon in terms of quarter-year seasons. We haven't fixed the Greater Moon's period yet.

[Iris]

Something that should be considered for the calendar is that Irdya doesn't always have one sun. After the Fall (which I set to occur on 1799 YW, with help or suggestions from the work or ideas of Aethaeryn, AI, Espreon, esr and myself) Irdya has two light sources, with the original sun being caled Sela, and the new sun being called Naia, by at least elves ([acronym=Under the Burning Suns (quartex)]UtBS[/acronym], [acronym=Invasion from the Unknown (shadowmaster)]IftU[/acronym], [acronym=After the Storm (shadowmaster)]AtS[/acronym]), merfolk (UtBS), humans (in the wiki, they named it; also mentioned in UtBS, IftU, AtS), dwarves (IftU) and orcs ([acronym=The Silver Lands (Espreon)]TSL[/acronym]).

Naia was created long before the Fall in this timeline, but long, long, long after all mainline campaigns (with the obvious exception of UtBS) and one somewhat-forgotten UMC campaign which once set the end of the main timeline for the History of Wesnoth wiki page, A New Order.

The time-of-day schedule when Naia was initially created is not known. We know that it changed with the pass of time (mentioned in UtBS:10 and IftU:10), most drastically after the Fall and the failed attempt to lift a third sun, and that UtBS, IftU, AtS and TSL use the following schedule, with n standing for whatever is required for a scenario's strategical design:

First schedule:

• First dawn (Naia appears)
• First morning
• First midday (Sela appears)
• First afternoon (Naia hides first)
• First dusk (Sela hides)
• Short darkness (not so dark apparently)

Second schedule (longer than the first schedule):

• Second dawn (Naia?... apparently farther away, appears)
• Second morning
• Second midday (Sela, apparently, appears; not as bright as Naia in the first schedule, but brighter than before still)
• Second afternoon (Naia hides first again... I think)
• Second dusk (Sela?... hides)
• Long darkness, part 1
• Long darkness, part 2, a quarter moon appears in the pic
• Long darkness, part 3
• Long darkness, part 4, Naia's light starts to illuminate that section of Irdya

I do not know if whoever made these images actually knew of the relevant bits mentioned in UtBS:1 (defining Naia as the sun appearing on the first dawn) and UtBS:10 (defining Sela as the original sun) and intended Sela to have become farther away from Irdya and acquire that reddish hue. Or perhaps Naia is just too bright. I'm not an astronomer, either.

Not sure if Naia is a true sun either. If it was, I guess it'd be rotating along with Sela over their orbit like a binary system? In such case, Irdya would have to be some farther away from it to be safe, I guess. But the suns' period cannot be as high as to allow them to swap places in the second schedule, can it? Then again, what are these suns orbiting? What galaxy is it?

I'm feeling dizzy already. I'll let someone else deal with this for me.

[Aethaeryn]

I always thought the second sun wasn't a real sun but just a real bright object in orbit that basically serves the same purpose to the pre-space-traveling civilization. I don't see how a conversion from a one-star to a binary system can be kind on a planet at all. Besides, it would be really powerful magic to create another star.

[Ardent]

How about turning a gaseous planet into a dwarf star?
If it is near the critical mass, with just a bit of magic you could send it over the brink

[thespaceinvader]

Second moon? Where did THAT come from o_O you'd thinkk someone might have mentioned it over the course of history I'd agree that modelling the solar system is a good idea, particularly given the different calendars that pop up. Although I'd understood both new 'suns' to be bright objects in orbit around the planet rather than anything else. Particularly the second one, given the opening of UtBS...

[melinath]

What exactly is the status of UMC Dev as lore? Also, is the two-sun thing really something we need to worry about now? Perhaps we should focus first on getting a calendar for the mainline time period.

[thespaceinvader]

Debatable. Personally, I'd consider most of S_M's post UtBS campaigns to be canon, but not a lot else currently - the other semi-canon campaigns have either been mainlined (LoW, DM) or fallen off the face of the earth (That sailing one... Fleeing Elensefar, was it called?)

[Daxion]

Please keep in mind, that in a biary-star system not all orbits are stable and periodic.

from Wikipedia:

Science fiction has often featured planets of binary or ternary stars as a setting. In reality, some orbital ranges are impossible for dynamical reasons (the planet would be expelled from its orbit relatively quickly, being either ejected from the system altogether or transferred to a more inner or outer orbital range), whilst other orbits present serious challenges for eventual biospheres because of likely extreme variations in surface temperature during different parts of the orbit.

While this seems trivial, this has another interesting effect.

Quoting from: Elisa V. Quintana, Jack J. Lissauer (2007). "Terrestrial Planet Formation in Binary Star Systems". arΧiv: 0705.3444v1. http://arxiv.org/abs/0705.3444.

Binary companions also limit the extent of the terrestrial planet region in
nascent planetary systems orbiting one member of the stellar pair.

To me this seems that at least the motion of the second star is mainly decoupled from the day/night cycle.

(...) we conclude that the constraint qB=10 AU is
sufficient for binaries to leave terrestrial planet systems unperturbed. With
smaller binary periastron values, the resulting extent of the terrestrial planet
region is diminished. When binary periastron decreases to 5 AU, the typical
system extends only out to ap ∼ 0.75 AU and no system has a planet with
semimajor axis beyond 0.9 AU (but note that we did not perform simulations
with qB = 5 AU and small eB ).

Keep in mind that an AU is the average distance Earth-Sun. Meaning that the second sun is
at least 5 AU away (if not larger). And that means the second sun is not very big in the sky.

Another problem I do have with 2 suns is: there isn't really any know process that transforms a stable binary-star system into
a single star system. Except a thermonuclear (Type Ia) supernova. I can imagine that a planet might survive such an event, I'm sure it would have a very catastrophic effect on the biosphere.

In my opinion this rules out a binary star system. At least from the physics stand point (we could still fiddle with magic in there).
Having a different type of object as a moon which glows, is from this standpoint possible, however I don't know of any effect that can bring an
asteroid-sized object to glow like a sun over the period of several years. Geothermal and nuclear reactions come to mind, but none of them should be able to create a surface temperatur of about 4-6k degree Kelvin.

So much from the physics side

-Dax

[AI]

Naia was lifted into the sky to "banish the darkness". As the only way to do this with binary stars would be to place the planet at L1 (between the stars), which is unstable, it seems more likely it was placed in a sela-synchronous orbit around irdya.

The orbit obviously changed since then, the question is how and when. A possibility is that the lifting of Gaia interfered, causing one satellite to come crashing down while making the other's orbit highly eccentric.

[thespaceinvader]

Why this fixation on a binary star system? A lit moon would work just as well, and make a lot more scientific sense.

[Skrim]

I also very much doubt that Naia is a real star. The amount of matter needed to create a real new star, and the size of the new star, ought to dwarf the dimensions of Irdya itself(unless Irdya is ineffably huge, which I somehow doubt).


I think Naia would actually be a ball of fusing plasma much, much smaller than an actual star, and much closer to Irdya than Sela(which is an actual star). As for explaining how the plasma is being held together and maintaining fusion temperatures(without enough mass for gravity to the job as in a real star), we can invoke magic. Given the canonical abilities of magic in the Wesnoth-verse, and given that Naia was constructed by the High Council of Archmagi, I think it's safe to limit it's role to this much.

[AI]

In case I wasn't clear, a sela-synchronous orbit around irdya means it orbits the planet, staying in the shadow of the star's light. (thus illuminating what would have been night)

[Skrim]

A "lit moon" or a fusing ball of magically-confined plasma or some other radiant satellite could fit into the orbit described by AI, constantly being 'eclipsed' by Irdya. Though, it's orbit did go eccentric at some point to produce the Long Dark.

[thespaceinvader]

Ah, i see what you mean, AI.