Axial Tilt

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Thorf
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Axial Tilt

Post by Thorf » Fri Apr 10, 2009 3:46 pm

I'm trying to find what information is given about Mystara's axial tilt in official sources, but I'm having problems coming up with anything.

From what I can see, there is frequent mention of the axis shifting due to the Rain of Fire - almost every Gazetteer mentions the event in its timeline - but no info on what exactly happened, or the nature of the axial tilt.

Does anyone know if there's any more official info on this? Is it just assumed that it's the same as earth's tilt, which is to say about 23.5 degrees?

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Re: Axial Tilt

Post by Zendrolion » Fri Apr 10, 2009 4:05 pm

I'm not 100% sure, but I don't remember any canon reference about the axial tilt, so I'd assume it to be the same of Earth.

BTW, I remember LoZompatore calculated the precataclysmic axial tilt using the info from PWAs about Ethengar being the former North Pole and KW being in the arctic region (which doesn't match with HW set's precataclysmic map). IIRC, he came up with the discoveries that seasonal variation between southern and northern hemisphere was inverted pre-BC 3000.
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Re: Axial Tilt

Post by Thorf » Fri Apr 10, 2009 4:23 pm

Yes, I remember Michele's work too. It's a very exciting study. :D

I want to analyse the official precataclysmic map, and see if it matches up at all with the world map, or if it was effectively just a drawing. (I'm thinking it was most likely just an artist's impression of the pre-Rain of Fire world rather than a proper map.)

I also want to take the world map - especially the updated map, with the expanded Far End Ocean - and tilt it back to its previous position. That's why I want to know the axial tilt; if I have the tilt in degrees, I can probably quite easily generate a map using the previous north pole.

Incidentally, I don't think Ethengar can possibly have been the north pole, because it's simply too far south. Ethengar is south of Landfall, which TM1 lists as being at 40 degrees North. Even if it were in the high 30s, that would still make the axial tilt 50 or 60 degrees! Nevertheless, GAZ12 does explicitly state that it was the former north pole. I think this will need to be glossed over. It seems possible that it could be within the precataclysm Arctic Circle... maybe...

Anyway it should be interesting to see how the map turns out.

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Re: Axial Tilt

Post by Ashtagon » Fri Apr 10, 2009 4:41 pm

Aren't the tropics and Arctic circles marked on some of the official maps? Those pretty much define the axial tilt for you, if marked.
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Re: Axial Tilt

Post by Zendrolion » Fri Apr 10, 2009 5:11 pm

Thorf wrote:Incidentally, I don't think Ethengar can possibly have been the north pole, because it's simply too far south. Ethengar is south of Landfall, which TM1 lists as being at 40 degrees North. Even if it were in the high 30s, that would still make the axial tilt 50 or 60 degrees! Nevertheless, GAZ12 does explicitly state that it was the former north pole. I think this will need to be glossed over. It seems possible that it could be within the precataclysm Arctic Circle... maybe...
Well, we're talking of an apocalyptic cataclysm, something like the one who caused the extinction of dinosaurs on Earth. From most all official written (i.e. maps excluded) sources, we know that:

1) the KW was covered in ice during pre-Blackmoor era (and some sources openly say it was under "polar icecap");

2) Ethengar was the North Pole (GAZ12); by the way, this would mean that the old northern polar opening (the small one) was located in Ethengar, and this could explain why Ethengar's terrain differs so much from that of surrounding lands (the Immortals "sealed" the old openings with an almost featureless plug).

3) The elven homeland of Evergrun becomes the South Pole after the Great Rain of Fire, while Blackmoor becomes the North Pole.

If we consider Ethengar as the old North Pole, we can guess the axial shifting. Moreover, this affects also Blackmoor's pre-cataclysmic position; as it's likely to have been between 40 and 50 degrees of latitude (at least, according to DA adventures), the axial shift must have been huge - otherwise we'll end up with a precataclysmic Blackmoor which sits still beyond the Arctic Circle, which is inconsistent with its description in the DA series.

So I don't think a 50-degree axial shifting would be a problem - quite the opposite, indeed. After all, the ancient world was destroyed by it. :shock: :twisted:

Obviously all of this doesn't match with HW precataclysmic map, which is contradicted by almost all official written sources.
Ashtagon wrote:Aren't the tropics and Arctic circles marked on some of the official maps? Those pretty much define the axial tilt for you, if marked.
That's right, of course. :)
So probably the tilt it's the same of Earth (at least judging from the position of circles in HW set's Outer World map).
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causes of their victories and defeats, so as to avoid the defeats and imitate the victories" N. Machiavelli, The Prince, XIV, 5

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Re: Axial Tilt

Post by Thorf » Fri Apr 10, 2009 5:22 pm

Ashtagon wrote:Aren't the tropics and Arctic circles marked on some of the official maps? Those pretty much define the axial tilt for you, if marked.
Aha... Very interesting. I've always wondered what decided the position of the tropics and Arctic circles. Thanks!

Unfortunately they are marked somewhat imprecisely on the official maps. They look to be in the region of 21 or 22 degrees from the equator or poles. It would probably be no problem going with the real world's 23.5. (The real world actually doesn't have a completely fixed axial tilt, but we don't need to go into that for Mystara.)
Zendrolion wrote:So I don't think a 50-degree axial shifting would be a problem - quite the opposite, indeed. After all, the ancient world was destroyed by it. :shock: :twisted:
I agree with all your points. My problem was that I was assuming the world started off with no axial tilt - 0 degrees - which needn't be the case at all, now that I think about it. So actually the tilt can be as big as we need it to be, and we can define the current axial tilt at whatever value we want - i.e. the same as real world earth, so that the seasons are familiar to us. So if the change in tilt was 50 degrees, it means the original tilt was -27 (or 73) degrees (I think both numbers end up being the same thing).

Thanks! :D
Obviously all of this doesn't match with HW precataclysmic map, which is contradicted by almost all official written sources.
That doesn't affect my wanting to convert the projection and apply an axial tilt to it so that we can see just how much (or how little) it really fits. :D Even if it's totally wrong, we can still use the coastline shapes to make a more accurate map.

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Re: Axial Tilt

Post by night_druid » Fri Apr 10, 2009 6:22 pm

I'd assume it to be reasonably close to Earth's, if Mystara experiences seasons. As far as the Blackmoor explosion, that seems to have triggered a chain-reaction of magical effects; I'm not sure the explosion alone would be enough to cause a tilt without being so big that it'd kill off all life on the planet. Nevermind the polar caps being blown off (which would have choked the atmosphere to an unbreathable state unless magic were involved). I'd just assume that both before and after the Blackmoor explosion the planet had an Earth-like tilt. ;)
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Re: Axial Tilt

Post by Chimpman » Fri Apr 10, 2009 6:39 pm

Hi Guys! This is a really interesting conversation, but I'm wondering if a few folks with better knowledge than I can better clarify a few things for me. First, let's see if I have the concept of axial tilt right.

Axial tilt: The Earth (or Mystara) spins during its orbit (creating day/night cycles). If we were to imagine a giant rod being stuck through the planet, from north pole to south pole, this would be the axis from which the earth spins. If that pole were completely perpendicular (90 deg) to the orbit of the earth, that would be an axial tilt of 0, correct? It's not perpendicular, but instead tilted at some angle from the plane of orbit, giving it an axial tilt of 23 deg. This angle is also what causes the seasons.

I have to admit that I always assumed the shifting of the continents (moving Blackmoor to the north pole) was caused by something other than an axial tilt. Imagine if the earth's outer mantle was like the rind of an orange, sitting loosely atop the magma core. In this case would it be possible for the crust to shift without changing the axis of the planet? Hmmm... now that I think more on this I suppose that the polar openings would actually prevent such an occurrence. Without the openings I'm not sure that you can tie the spin of the earth (and it's axis) to the crust of the earth. With the openings, it seems like they can not be divorced at all.

Ok, so assuming that is is an axial tilt that shifts Blackmoor to the north pole, wouldn't that mean that the ancient world had vastly different seasons and lengths of days? For example (to take things to the extreme) if the axial tilt was 90 deg wouldn't that mean that the northern hemisphere would be in perpetual daylight during the summer months, and in perpetual night during the winter months?
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Re: Axial Tilt

Post by Gawain_VIII » Fri Apr 10, 2009 7:22 pm

The way I see it is that the axial tilt, when viewed from the solar plane, is the same as r/w Earth. The planetshift from GRoF did not effect the axis (again, when viewed from the solar plane) but rather the "earth" moved--essentially changing the direction the planet moved (froma planet-side PoV).

Try and visualize it thus:

Take a globe, and drill a hole from Lake Superior (50 N/90 W) through to French & Southern Antartic Lands in the south of the UIndian Ocean (approx 50S/90E)... This represents the "old axis". Place the globe on it's stand using the old axix and spin it. The axial tilt is still 23 degrees. When things blow up, the Earth shifts beneath the axis to match the current holes/poles--the axis (invisible line) itself doesn't actually change.

I hope that makes sense... I'm bad at describing the abstract thoughts that run through my head.

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Re: Axial Tilt

Post by Chimpman » Fri Apr 10, 2009 8:31 pm

Gawain,
That's pretty much the way I was viewing it as well. The more I think about it though, the more unsure I am that this could be possible. For the planet's crust to shift, yet the spin remain at 23 deg, wouldn't that mean that the entire planet's rotation would have to be stopped, the planet shifted, and then the spin started again at 23 deg?
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Re: Axial Tilt

Post by metal » Fri Apr 10, 2009 10:27 pm

I'm just thinking out loud (I'm not a scientist, nor do I play one on TV, and I didn't stay at a Holiday Inn Express last night).....
I think the shift would be possible-
1. Event that causes the shift of poles happens.
2. The planet starts to "tumble". Technically the poles would drift across the planet during this tumble.
3. The planet stops tumbling with the poles in their current positions.

During this tumble the planet doesn't speed up or slow down it's normal rotation. If you were standing on one spot on the planet your days may be out of wack (if you survived the GRoF) while the tumble happened.

Just spouting out an idea. I'm sitting here with a ball trying to figure this out.

Another thought-

Has anyone looked to see if there is any RW example to compare to? i.e. some planetary body getting smacked by something else to throw it off?

Off to search..............
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Re: Axial Tilt

Post by Thorf » Sat Apr 11, 2009 4:40 am

Yes, the seasons and indeed daylight hours would indeed be different from the modern world's. On the other hand, how about this:

The world's original axis was about -30 degrees. (At this stage this is just an example.) Official sources state over and over again that the Great Rain of Fire shifted the planet off its axis, so I don't think we can really get around that. The effect of the Great Rain of Fire was to throw the planet's axis to the current, earth-like position: 23 degrees. This means an overall change of 53 degrees or so, but the seasons and daylight hours would not be hugely different from before. They would however be reversed.

I think it all depends on where we define as axial tilt 0. This is what was confusing me at first, since I was assuming that the world started at an axial tilt of 0 before the Great Rain of Fire. But it was never defined as such, so there's no reason we can't start from a negative tilt. :)

I can't really comment on the discussion about the possibility of this. The fact is that official sources state it happened so much that we can't really do anything about it anyway. :?

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Re: Axial Tilt

Post by Zendrolion » Sat Apr 11, 2009 12:47 pm

Thorf wrote:Yes, the seasons and indeed daylight hours would indeed be different from the modern world's.
Yes, as i said they were probably inverted: northern emisphere had winter while post-GRoF would have had summer, and so on.
The world's original axis was about -30 degrees. (At this stage this is just an example.) Official sources state over and over again that the Great Rain of Fire shifted the planet off its axis, so I don't think we can really get around that.
I agree: almost all official sources talking about the GRoF agree on the fact that the cataclysm caused the shifting of the planet's axis. We can't ignore them outright.

By the way, looking at OW precataclysmic poster map (the one included in HW set), we can see that the GRoF made the axial tilt shifting about 40 degrees from its pre-cataclysmic position. Apart from other problematic features of that map, the 40 degrees shifting is more or less consistent with Ethengar being the North Pole before BC 3000, and Blackmoor being beyond the Arctic Circle after BC 3000 (this would put Blackmoor at about 40 degrees of latitude, and Ethengar's about that latitude also).
I think it all depends on where we define as axial tilt 0.
IMO axial tilt 0 would match, on the northern emisphere, the middle point of a line connecting the pre-cataclysmic (Ethengar?) and post-cataclysmic (Blackmoor?) North Pole.
This is what was confusing me at first, since I was assuming that the world started at an axial tilt of 0 before the Great Rain of Fire. But it was never defined as such, so there's no reason we can't start from a negative tilt. :)
IMO pre-GRoF xial tilt 0 is not to be hoped; a planet's axial tilt of 0 would mean that climate is rather stable, to the point of absence of seasonal changes - climate and temperatures are always the same year-round, there are not everlasting day and night phenomenons beyond polar circles, and so on. This would mean that in Blackmoor's time Mystara had no seasons - something I'd like to avoid, and which is not supported by DA modules either.
Last edited by Zendrolion on Sun Apr 12, 2009 6:47 pm, edited 1 time in total.
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Re: Axial Tilt

Post by LoZompatore » Sat Apr 11, 2009 6:30 pm

The world's original axis was about -30 degrees. (At this stage this is just an example.) Official sources state over and over again that the Great Rain of Fire shifted the planet off its axis, so I don't think we can really get around that. The effect of the Great Rain of Fire was to throw the planet's axis to the current, earth-like position: 23 degrees. This means an overall change of 53 degrees or so, but the seasons and daylight hours would not be hugely different from before. They would however be reversed.
I definitely agree with this theory ;)
Zendrolion explained very well the whole thoughts about the evaluation of axial tilt, nevertheless.
When I tried to evaluate the axis shift in my old topic about Blackmoor I was thinking about something very similar to what Thorf wrote above. If you want to adhere to canon remember that, accordingly to DA modules, there should be seasonal variations in pre-cataclysmic Blackmoor, which means that before the Great Rain of Fire Mystara's axis should have been tilted, too. ;)

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Re: Axial Tilt

Post by Chimpman » Thu Apr 23, 2009 8:12 pm

Ok, I'm still trying to get a handle on this. So if Ethengar was the old north pole (complete with polar opening), then much of the KW would have been under ice at the time. What would the areas north of the KW have been like? Would (for example) Hyborea have been in a more temperate zone? What would have been the ancient position of the equator?
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Re: Axial Tilt

Post by Birchbeer » Mon Apr 27, 2009 9:25 pm

Another side point, would the moons have been altered in position to Mystara as well so they would remain consistent? Otherwise wouldn't the moons pre cataclysm looked like the were going backwards in the night sky?

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Re: Axial Tilt

Post by Hugin » Mon Apr 27, 2009 10:00 pm

Birchbeer wrote:Another side point, would the moons have been altered in position to Mystara as well so they would remain consistent? Otherwise wouldn't the moons pre cataclysm looked like the were going backwards in the night sky?
That is a really interesting question that I've never thought about before! I'm not sure but, I think it would only affect the perceived altitude of the moon in the sky. Any other ideas out there?

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Re: Axial Tilt

Post by micky » Mon Apr 27, 2009 10:45 pm

interesting thread and discussion.. nothing to add since I slept through earth science in school 20 odd years ago :lol:

but good reading
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