[World Design] Implications of a longer day

[Baron Opal]

That is, until you factor in the local nature gods and goddesses, whose worship make the climate more clement.

Which is a great solution. The weather is controled, although perhaps guided might be a better word, by the local powers-that-be. Out beyond the borders of the kingdom the weather is untamed, made even more violent as a backlash against the control exerted within civilized bounds. If you're brave enough, or desperate enough, you could hitch a ride on the hurricane force winds and let them blow you across the boundary.

 

[Gez]

Which is a great solution. The weather is controled, although perhaps guided might be a better word, by the local powers-that-be. Out beyond the borders of the kingdom the weather is untamed, made even more violent as a backlash against the control exerted within civilized bounds. If you're brave enough, or desperate enough, you could hitch a ride on the hurricane force winds and let them blow you across the boundary.

Also, in classical pagan religions, there was the belief that if the temple to so-or-so deity was profaned, the city or country risked natural disaster. (In fact, the destruction of pagan temples such as the Alexandrian Serapeum under Theodosius, without any apparent consequence, was instrumental in getting Christianity to replace paganism as it "proved the falsity of the old beliefs.")

Well, except this time, it wouldn't be baseless superstitions.

 

[The Grumpy Celt]

I am following this closely because it is surprisingly similar to a setting I am developing for a novel I am planning. The setting I am developing also has the lengthened period of day and night, and a secondary source of illumination that does not provide heat.

Basically, I had been fascinated by length of day on the moon, and the nature of it being the smaller body and satellite of a larger celestial object.

Further, I was interested in the fact the Centari solar system is binary; Alpha Centauri A & B (Proxima doesn’t count). Any planet in orbit of either of those stars will receive some illumination, but a negligible amount of heat, from the other star.

The planet I am developing is a traditional celestial body, rather than the islands. However, I’ve put all the significant bodies of water on one side, the side facing the larger celestial object.

The side facing the larger object and with the water is the side of “life,” the side without water and facing the darkness is the side of “death.”

I am very interested in how things develop in your setting as it is markedly similar to mine.

 

[Aexalon]

The setting I am developing also has the lengthened period of day and night, and a secondary source of illumination that does not provide heat.

Basically, I had been fascinated by length of day on the moon, and the nature of it being the smaller body and satellite of a larger celestial object.

Further, I was interested in the fact the Centari solar system is binary; Alpha Centauri A & B (Proxima doesn’t count). Any planet in orbit of either of those stars will receive some illumination, but a negligible amount of heat, from the other star.

Are you writing hard-sci-fi, or fantasy? Are you working with the following assumptions?

• Being a wide double star with a period of 80 earth years, and distances varying from 11.2 to 35.6 AU, Alpha Centauri A being a bit more (1.5x) luminous than our sun (meaning your habitable zone is going to be around 1.2 to 1.3 AU), and Alpha Centauri B being a bit dimmer (0.5x), you shouldn't be having too many periodical effects (the difference in energy input between maximum distance and minimum distance is about half a percent).
• You would have two other light sources of course: your planet -which most likely will be equally stationary in the moon's sky, and a magnitude anywhere between 4 and 12 (depending on distance, size and albedo; I presume you're talking about a gas giant here) lower than the sun, but relatively "big"-, and the 2nd star -with a magnitude varying between 5.7 and 8.5 lower than the sun, but rather "small"- (resulting in a variation in energy input between minimum & maximum distance of 0.4%).

(for the audience: An AU is the distance between the Earth and the Sun, also known as an astronomical unit. A magnitude is a relative unit of luminosity, equal to the 5th root of a factor of 100. I.e. something with an apparent magnitude 5 higher than something else seems to shine 100 times as bright).



Back on topic: the planning committee is currently examining ways to keep people living predominantly on the planetside faces of the islands. Punitive arrangements where the Worldtree only mitigates temperatures on the planetside face proved unworkable (the weather caused by these +50 to -30 temperature changes would have to somehow miraculously stop at the border between planetside and starside ... too deus-ex-machina).

The planet I am developing is a traditional celestial body, rather than the islands. However, I’ve put all the significant bodies of water on one side, the side facing the larger celestial object.

The fact that you have a more traditional large moon/planet-like object makes it easier to differentiate between the different sides. We can't have every island of Garden miraculously have temperature-difference-dampening water bodies on their planetside, but not on their starside.

Which is a great solution. The weather is controled, although perhaps guided might be a better word, by the local powers-that-be. Out beyond the borders of the kingdom the weather is untamed, made even more violent as a backlash against the control exerted within civilized bounds. If you're brave enough, or desperate enough, you could hitch a ride on the hurricane force winds and let them blow you across the boundary.

Since we're having to rely on a Garden-wide effect created by the Worldtree Aiëde, having such heavy-handed "zones of save living" (and there'd have to be one on almost every island) proved too complicated, as indicated above. For other, less convoluted setups, where you could get by with one protected zone, it would work very well, I think.

Also, in classical pagan religions, there was the belief that if the temple to so-or-so deity was profaned, the city or country risked natural disaster. (In fact, the destruction of pagan temples such as the Alexandrian Serapeum under Theodosius, without any apparent consequence, was instrumental in getting Christianity to replace paganism as it "proved the falsity of the old beliefs.")

Well, except this time, it wouldn't be baseless superstitions.

The idea of Garden being endangered by the death of the Worldtree is deeply engrained into the campaign setting. The wound struck by the Dreaming Dark festers, and it would be only a matter of time until the Dreaming Dark itself once again found the runaway planet, now no longer capable of escaping anywhere. The tentative campaign title "At World's End" should be sufficiently indicative of this

There is one implicit and simple reward arrangement: planetside has light during the night, enabling the inhabitants to do useful things at night without having to resort to artificial illumination or types of darkvision.

Another (mixed reward/punitive, depending on your interpretation of the default state) arrangement could see (certain types of) magic only work in planetlight / in sight of the planet (i.e. it's not because the suns are overhead, that the half-full planet's light doesn't count anymore). This would cause magic-rich cultures to dislike venturing onto starside of their (or other) islands, while leaving room for magic-low/void cultures to have starside all to themselves. The next step could be to tie the strength of said magic to the phase of the planet, and/or link the refresh cycle to those same phases. Problem is that the period of the planet's phases is ALSO 60 standard hours, too long to not have to adjust per-day type spellcasting classes (not that this is a bad thing, but I'm just noting it).

 

[Pbartender]

30h/10h/10h/10h:
The upside: no waste of midnight light, less long day.
The downside: assymetrical, complicated, not that great a solution to the long waking hours problem.
Applicability: might be a good template for diurnal animals.

Do any of you have an opinion on these three? Other ideas for cycles? Different applicabilities for these or other cycles?

Why not take this cycle and adjust it to 20/10/20/10? Creatures stay awake during the daylight and the nighttime hours, but sleep through dawn and dusk. In effect, you'd be treating one entire day as two 30-hour "days" -- one during the daylight hours, the other in (relative) darkness).

• It's symmetrical.
• At 30 hours per wake/sleep cycle, it's very, very close to the earth standard we're used to.
• It retains a reasonable ratio of waking to sleep.
• You get a very cool effect in which every other "day" is dark, which makes the world feel a little more alien right off the bat.
• Sunrise and sunset become important events (akin to midnight in both cases) that are rarely observed due to sleep cycles.

Also remember that you can different cycles for different creatures. I can see native creatures, plants and monsters that are active during only one half of the cycle or the other. That by itself could make for someinteresting plot developments and complications...

For example, most vampires only live on the side of the moon away from the planet and only come out during the 30-hour night.

 

[Aexalon]

I may have ignored an early participant ... rectifying that now, even if it means another sidetrack

Interesting that this is brought up. My homebrew revolves around two stationary solar bodies, but each set apart from each other and also have planetary bodies that revolve between them. The orbit or the primary world (where my homebrew takes place) has a 36 hour day cycle, with a month consisting of 6 weeks (10 days each) and 16 months to a year.

First let me sart off by staing that the primary planet I use in my homebrew is *huge*; nine times the size of Earth. It has nine satellites, each one the size of Earth. Eight of these moons are linked werecreatures they affect by alignment. The ninth, actually has an atmosphere much like our own and supports its own ecosystem.

I'm not entirely sure how my lunar cycle works, I just eyeball it. One thing though is a prophecy, should all moons ever be full for one full night, a cataclysm could befall the world, tearing it to pieces and quite possibly become an asteroid belt once all pieces settled.

With stationary you probably mean that their orbits are circular (unlike Alpha Centauri A & B's). With respect to any planetary bodies in-system, they could be considered unmoving. They do move relative to the stellar background, of course, but such movement also already results from the path your inhabited moon takes in the system.

When you said "that revolve between them", do you mean in a figure-8 pattern? That type of orbit is notoriously unstable. And with an orbital period of 1440 earth days, that would also mean that the stars are fairly close for a wide pair, and that your planet would have a significantly larger energy input in the middle than on either end (up to twice as much). Not criticism, just informing you. Nothing magic can't explain away, if necessary.

Nine times the size or nine times the mass? First there's the cube law, which (for example) means anything 3 times as big (in one dimension) has 27 times the volume. Then there's gravity, which compresses stuff the more there is of it. E.g. Jupiter's diameter is only ~18% bigger than that of Saturn (73% more volume actually, due to Saturn being flatter than Jupiter), yet is slightly over 3.3 times as massive.

Nine moons, nothing wrong with that. All of'em orbiting the central planet (likely a gas giant too), you'd have quite a visual spectable. Note that inferior moons (those closer to the planet than your inhabited moon) can only be seen as entirely full against the background of the planet itself (depending on what you call "full" of course. If 90% will do, this might not be the case, and you might be able to see them being full-ish almost anywhere in their orbit). Superior moons (those further away) can only appear full on the other side of the planet. Again, requiring perfection in "fullness" would require x-ray vision to see through the planet, but the 90% rule could mitigate that as well. If you want to do something with that doom scenario, I'd suggest rephrasing it as a conjunction (i.e. a lineup of all moons on one side of the planet, preferrably including the sun as well ... think "Lara Croft: Tomb Raider"), instead of "full moons" which might very well be invisible. When viewed from your inhabited world when standing on the terminator (the edge between dark and light), you'd see a multiple eclipse towards where the sun is, and multiple full moons (and the full planet) directly opposite them in the sky. That would definately rock (maybe even literally).

All this gibberish of mine presumes a somewhat physically realistic setup, of course ... which might not be (nor need to be) the case .

 

[Pbartender]

Here's something that just occurred to me...

Navigation and Timekeeping.

As a byproduct of living on a tidally-locked world, navigation and timekeeping become much, much easier prospects. Historically, one of the biggest problems of navigators was being able to tell what longitude you were at, because everything in the sky moves from east to west.

On this tidally-locked world, however, you have a single object (the mother-planet) which does not move (appreciably) in the sky, and changes its phase throughout the day... If you live on the planet-side of the moon, even primitive observers could easily come up with a system for navigation (where is the planet in the sky?) and daily timekeeping (what phase is the planet in?).

That alone could make a significant difference in the development of any native cultures (and alien settlement as well).

 

[Angel Tarragon]

With stationary you probably mean that their orbits are circular (unlike Alpha Centauri A & B's). With respect to any planetary bodies in-system, they could be considered unmoving. They do move relative to the stellar background, of course, but such movement also already results from the path your inhabited moon takes in the system.

The twin suns are unmoving. And I forgot that I recently made a change to the cosmology. There are 7 planets that revolve between them, only the middle one locked in a figure 8 revolutionary pattern. Three revolve around one sun, while the other three revolve around the other sun. The primary planeyt, on which the adventures mainly take place, has a huge orbit, revolving around both suns. Due to the wide berth, the sattelites from my homebrew have no chance of being caught in a different gravity well.

When you said "that revolve between them", do you mean in a figure-8 pattern? That type of orbit is notoriously unstable. And with an orbital period of 1440 earth days, that would also mean that the stars are fairly close for a wide pair, and that your planet would have a significantly larger energy input in the middle than on either end (up to twice as much). Not criticism, just informing you. Nothing magic can't explain away, if necessary.

Well, the middle of the system is the one planet that revolves around both suns in a figure eight pattern. The amount of space in between both suns is three times the amount of space between Earth and our Sun. I figure that is just the right amount of space for the figure pattern revolving planet to be able to support an ecology, without being too overheated.

Nine times the size or nine times the mass?

Nine times the size. Just imagine my world world as Earth having porprtions multiplied by 9. I don't think anyonge would have a problem finding parking space in such a scenario.

Nine moons, nothing wrong with that. All of'em orbiting the central planet (likely a gas giant too), you'd have quite a visual spectable. Note that inferior moons (those closer to the planet than your inhabited moon) can only be seen as entirely full against the background of the planet itself (depending on what you call "full" of course. If 90% will do, this might not be the case, and you might be able to see them being full-ish almost anywhere in their orbit). Superior moons (those further away) can only appear full on the other side of the planet. Again, requiring perfection in "fullness" would require x-ray vision to see through the planet, but the 90% rule could mitigate that as well. If you want to do something with that doom scenario, I'd suggest rephrasing it as a conjunction (i.e. a lineup of all moons on one side of the planet, preferrably including the sun as well ... think "Lara Croft: Tomb Raider"), instead of "full moons" which might very well be invisible. When viewed from your inhabited world when standing on the terminator (the edge between dark and light), you'd see a multiple eclipse towards where the sun is, and multiple full moons (and the full planet) directly opposite them in the sky. That would definately rock (maybe even literally).

Well, I'm not sure about the orbot of the moons, but they are all visible from the surface of the planet, each phase visible to anyone looking up into the night sky. Cunjuntions, eh? I may have to relook at that Dragon magazine article.

 

[Angel Tarragon]

Here's something that just occurred to me...

Navigation and Timekeeping.

<snip>

If this is in reference to my homebrew, I am going to say that navigation is readily available and 52% of the world has been explored and mapped, for what the PCs know. And the mother-planet doesn't move so much, she revolves on her axis and only circles the center of the system to complete one yearly cycle.

 

[Pbartender]

Nine times the size. Just imagine my world world as Earth having porprtions multiplied by 9. I don't think anyonge would have a problem finding parking space in such a scenario.

Yeah, you have to be careful, there... If you aren't using magical D&D handwaving, having a much larger planet equates to a much higher gravity.

Using off the top of my head, back of a napkin physics (anyone is welcome to correct and fill in details if I'm too far off, here...), a planet with a diameter 9 times that of earth will have a volume (and, in general, a mass) roughly 729 times (9 cubed) that of earth. Now, the people standing on the surface are 9 times farther away form the center of gravity, which means they will feel approximately 1/81th the total gravity.

Or, gravity should be about 9 times stronger at the surface of this planet than earth normal.

Meaning, someone weighing 200 pounds on earth will weight nearly a ton on this planet.

Of course, it's D&D, so if you aren't concerned with that, you can simply ignore it.

If this is in reference to my homebrew...

No, it's in reference to Aexalon's tidally-locked world.