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Old Mar 23 2009, 11:52 PM   #41
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Default Re: ThreadFall Charts & Pern Calander

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The threadfall chart from Dragonsdawn - wasn't that just for the first set of falls? I'm pretty sure it's neither comprehensive nor complete.

*checks*

Ah yes - just the falls on the first 50 days of the Pass. There would presumably be blanket coverage of the planet, with fairly predictable variations from the baseline pattern illustrated in that chart over time. Another thing to remember - Threadfall ramps up to a higher frequency and shifts about further into the Pass as well.


As far as Fall patterns go, astronomically it doesn't make a great deal of sense. The easiest way of handwaving an explanation is to bring Pern's magnetosphere into the equation. Variations in the axial tilt of the red star and its orientation relative to Pern are pretty meaningless parameters, as the RS goes in and out of the system very fast relative to the length of the Pass (Kepler's laws won't allow things any other way ). You need the Red Star to seed pretty much the whole inner system with Thread, and then just let Pern sweep through it one orbit at a time. Predictability of Falls depends on a local phenomenon, and magnetic interactions plus SERIOUS clumping of the Thread ovoids are the best candidates. Apparent fall direction can be treated much like the radiant of a meteor shower, but much like meteors, in the absence of any other controlling factor you're not going to be able to predict where on the planet is going to get the best show.
Before blaming the magnetosphere, how about giving the two moons their due...
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Old Mar 24 2009, 05:14 AM   #42
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Default Re: ThreadFall Charts & Pern Calander

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Before blaming the magnetosphere, how about giving the two moons their due...
Because I'm an astrophysicist, and we blame magnetic fields for everything?

Seriously though, I'm doing it because Thread doesn't fall in anything as obvious as a Pernese lunar cycle.

Timor we can pretty much ignore completely. It's comparable to the Martian moons in size and distance from its primary, and on astronomical scales is pretty much insignificant - it's not even going to be a functional part of raising tides compared to Belior's influence. As for Belior, it's still just a lump of rock, and gravity is a pretty weak force. I can see Belior collecting its own halo of Thread and some increase in minor cratering throughout the Pass (and boy, you could do some great remote experiments on lunar geology with spectroscopy of the impact debris), but it's simply too far away from Pern to be much of a factor.

Yes, it's possible to come up with a scenario where Belior was the major influence on Threadfall patterns, but there are several problems with that. First, why didn't the colonists mention it in Dragonsdawn? With all the exploration they were doing over the source of Thread, they'd have mentioned that if it were an issue. Second, the total lack of any lunar-cyclic behaviour in Threadfall patterns. Third, unlike the oceans, Thread ovoids are not a bound system on Pern-local scales, and Pern itself must be added into the equation. In terms of the volume of ovoids that would fall within the timescale of a single Thread-fall, any tidal forces from Belior that act on the ovoids would act on a large virialised random field pretty much equally, and would be more or less insignificant relative to Pern's own gravitational attraction - and to my mind that really argues against generating significant clumpiness.

It could be made to work your way, true - but I think it's far easier to handwave over the problems in both models with a bit of EM.
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Old Mar 24 2009, 04:11 PM   #43
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Default Re: ThreadFall Charts & Pern Calander

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Because I'm an astrophysicist, and we blame magnetic fields for everything?

Seriously though, I'm doing it because Thread doesn't fall in anything as obvious as a Pernese lunar cycle.
Didn't Wansor have equations that used the planetary bodies in the Pern(Rukbat) system to calculate when thread was going to fall at any one place?

If so, then it seems (according to AMC), that it is the planetary bodies and not the electromagnetic field of Pern which is the causation of the thread fall at any one place.

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Old Mar 24 2009, 04:29 PM   #44
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Default Re: ThreadFall Charts & Pern Calander

Yes but at planetary distances, surely it is their magnetic fields interferring with Pern's that causes the problems.

Which bring us back to .....
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Old Mar 24 2009, 04:56 PM   #45
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Yes but at planetary distances, surely it is their magnetic fields interferring with Pern's that causes the problems.

Which bring us back to .....
I would think that their EM fields would have less effect on Pern than their gravitational fields.

And don't forget that the "debris" comes at Pern in waves, as there were several waves that went past the Dawn Sisters in AtWoP.

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Old Mar 25 2009, 12:40 AM   #46
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Default Re: ThreadFall Charts & Pern Calander

Much of Threadfall just doesn't work.

The rapid periodicity almost has to be linked to rotation, as does the north to south progression (but never south to north). So the axial tilt and orientation of Pern, and the Red Star, and the orbital periods of the moons are going to figure in somehow. No doubt gravitation and magnetic fields are factors as well.

The sheer volume of Thread dragged into the inner system just doesn't fit with a dinky little Pluto-type planet. The Red Star desperately needs to be retconned from a Plutino into a gas giant if it's going to drag enough of this crap into the inner system to create a 50 year rain. Heck, make the thing a brown dwarf that is "almost" escaping Pern's orbit at outer end of its orbit and therefor "hovering" in the Oort cloud long enough to gather enough of this crap to then drag it to the inner system. Another possibiliy could eschew the Red Star enitrely and have Thread originate in the gas giant's atmosphere as an indigenous life-form. As it comes in toward the inner edge of its orbit it could be shedding atmosphere like Osiris and spinning off Thread as it does so.

Just a few of the things the author could have dome (had she started writing these stories in the last few years.
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Old Mar 25 2009, 03:35 AM   #47
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Default Re: ThreadFall Charts & Pern Calander

That's like saying that Jules Verne would have been able to write 'Around the World in 80 Minutes'.
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Old Mar 25 2009, 04:10 AM   #48
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Default Re: ThreadFall Charts & Pern Calander

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That's like saying that Jules Verne would have been able to write 'Around the World in 80 Minutes'.
Nah, that'd be boring, and he was very much into genre. Round the Universe, more like!
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Old Mar 25 2009, 04:20 AM   #49
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Default Re: ThreadFall Charts & Pern Calander

OHMYGAWD

"Jouney to the Centre of the Galaxy"

Captain Nemo and his starship The Ether.
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Old Mar 25 2009, 05:43 AM   #50
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Default Re: ThreadFall Charts & Pern Calander

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"Jouney to the Centre of the Galaxy"
You want to read some Vernor Vinge then. Or even better, Greg Benford.
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Old Mar 29 2009, 11:25 PM   #51
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Default Re: ThreadFall Charts & Pern Calander

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That's like saying that Jules Verne would have been able to write 'Around the World in 80 Minutes'.
Sure. But authors have a right to update their work if they wish. Many don't simply because they've moved on and don't care to do so; it's not profitable for their publishers; hidebound fan(atic)s would go into apoplexy. The author sells well enough and is popular enough, she could probably get away with it.

Heck, they "remaster" albums all the time.
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Old Dec 5 2011, 01:49 PM   #52
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Default Re: ThreadFall Charts & Pern Calander

hey there... I see the links here have died. this is quite an old thread and all :p I'd love to see an example of how to attempt a threadfall chart, and if anyone has helpful links that would be much appreciated. I'm grateful to Yakima for the hard work and starting this topic that had so much advice for me to use. I'd LOVE to see the chart! I don't now if I'll be making a finished chart of my own, but my main goal is to calculate when and where thread is falling for my weyr calendar... basically same reasons as Yakima. Is there anywhere I can see a visual example like this by fans?
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