A question ...

[Hans]

Originally Posted by Sandi

Didn't AIVAS say something about their makeup indicated some form of intelligence? Maybe they interact telepathically.

Sandi, I always thought it was the opposite and Pern's enemy is mindless. Anne has stated this many times but you never know if things change.

[Spaceman Spiff]

Originally Posted by P'ter

W - e - l - l : perhaps the Red Star's apapsis is BEYOND the oort cloud and there's a gas giant out there on which thread fulfills the niche occupied by ants on Earth. The planet's viability as a habitat would probably have to depend on a high rate of geothermal activity.

In our star system at least, the Oort cloud is a light-year from the sun. I don't know if Pern's system is different, but that it's really stretching it for the Red Star to swing that far out so (relatively) quickly. So in that case, I highly doubt that it would swing out farther even than the oort cloud. I also doubt that there is a gas giant that close, or it would probably disturb the Oort cloud and the planet wouldn't be able to drag such a massive tail of material behind it, not to mention the phenomenal effect it would have on the eccentric's orbit. It would probably be kept in the giant's orbit rather than going back to Rukbat, or at the very least, it would certainly not have such a relatively regular elliptical orbit around Rukbat.

Also, the eccentric planet is not a habitat for Thread. The ovoids originate in the Oort cloud, and any that are on the surface of the planet are only pulled in by its gravity. Thread could not live there, since there is nothing for it to eat to sustain its already short and destructive life-span outside of its shell.

[P'ter]

In that case; on what does it feed in the oort cloud? Given the conditions out there.

Unless they evolved during the Rukbat system's formation when everything was a lot smaller and therefore closer and hotter. This would mean that they've been in stasis ever since.

[Spaceman Spiff]

They're certainly not in stasis, otherwise Aivas's zebedee project would have failed. I can't remember details, but there is something that springs out of them, I think that Aivas theorized it may have been for reproduction or a foreign parasite or something like that. But even if it were a parasite, it shows that life definitely can function in the Oort cloud.

As for its sustenance in the Oort cloud, there may be an entire space-faring ecosystem. Actually, if Thread actually evolved in space, there is almost certainly other varieties of life there, as evolution branches out in all directions. It may not be as diverse as on earth because of the harsh conditions, but there would surely be something else that evolved that Thread lives off, or even that lives off of Thread. Unless there is so little variety that they cannibalize each other.

[Sandi]

Originally Posted by Hans

Sandi, I always thought it was the opposite and Pern's enemy is mindless. Anne has stated this many times but you never know if things change.

This is an extract from page 341 of my copy of All The Weyrs of Pern. It is part of a conversation between Jaxom and Aivas.

"It is extrapolated by the closer examination of the Thread ovoids that there is life, not a you know it, and not even as we see it brought here by the Red Star, but a whole ecology of life-forms throughout the Oort Cloud. Some of them are probably quite intelligent, judging by the complexity of their nervous systems; but when they arrive here, they have lost most of their liquid helium and so can be termed only ‘rude mechanical.' It is these degenerate, warmth-tolerating forms that make it to the surface of Pern; they don't live long enough to replicate themselves there, of course or on the Red Planet. It is only these ‘mechanicals' that can reproduce without helium in Pern's orbit........."

[ghost8772]

of course it was also termed a very disorganised system by AIVAS in the same book. So, speculatively, the organism that becomes thread might have a different function and capabilities at -273C than at say 30C. it doesn't eat everything it touches until it gets warm.

[Hans]

Sandi, thank you for the quote. Hmm, that would mean they kind of die during the journey to Pern, doesn't it? And of course it poses an Annconsistency because of her saying she created a mindless enemy (as opposed to the intelligent enemy, the Nathi, from the colonists relatively recent history).

You quote also indicates that there are several kinds of Thread, because some of them are intelligent, thus some of them are not... überThread?

Thanks again, I never picked up on this obviously and it does need more attention *sigh* as so many things that keep lying around until there is time. Ah... to be able to go between times...

[edith]

Intelligence could mean an insect like intelligence, something relatively primitive, compared to a plant.
The thread that falls is possibly something that works very slowly at 3K- a way of digesting food or something, which, after the death of the "brain" of the ovoid carries on multiplying until it runs out of something. It could just be a mass of proteins (enzymes and the rest) that unravels (think of it as the ovoid's guts) as it falls and carries on digesting until it dies. It could even be a symbiote (like a mychorriza (sp)) that helps the "intelligent" part cope while it is alive in the low temperature region.

[Weyrbrat]

This is probably wrong, but in dragonflight the thread come down as dust when freezes. I'm not sure about the nighttime climate of Pern, but would thread freeze in the cold?

[Hans]

Correct Weyrbrat, "Crackdust, blackdust..." Yes, Thread freezes in cold/low temperatures.

[Spaceman Spiff]

[QUOTE=Hans;126319]Sandi, thank you for the quote. Hmm, that would mean they kind of die during the journey to Pern, doesn't it? And of course it poses an Annconsistency because of her saying she created a mindless enemy (as opposed to the intelligent enemy, the Nathi, from the colonists relatively recent history).[/color]
Thread ovoids are completely harmless to humans in space. But by the time Thread falls through the air where they fight it, it IS mindless. So yes, she created a mindless enemy.

But when Aivas says "when they arrive here, they have lost most of their helium", does that mean they have lost most of it within their shell on the journey through space toward Pern, or have they lost it when they break out of the shell through the atmosphere?

You quote also indicates that there are several kinds of Thread, because some of them are intelligent, thus some of them are not... überThread?

It would depend on exactly what you mean. If you are defining Thread as any life that comes from the Oort cloud, then definitely. But he said that there was a whole ecology, which means many different species. It's unlikely that every species acts in the same destructive way. There will be simpler forms of life, and more evolved and intelligent forms. Surely they come in different forms. Maybe they all have shells, but the insides are different. Some might have coils inside, some might just have a jelly, some might have a jumble of balls, who knows. Some might be completely harmless if they fell on Pern. Or perhaps it's only the destructive ones that have the extremely resilient shells to make it through the atmosphere far enough to spill out its coils, and the other lifeforms have less tough shells and burn up entirely, not getting a chance to fall on Pern at all. There might even be massive asteroid-like ovoids with huge alien bodies inside. It could be that the asteroid that collided in Skies of Pern WAS one of these massive life-forms that only appeared to be a normal asteroid! (this is really far out, but you never know) But I think it very unlikely that all of them are like the destructive threads that make it to the surface of Pern.

[Spaceman Spiff]

Originally Posted by ghost8772

of course it was also termed a very disorganised system by AIVAS in the same book. So, speculatively, the organism that becomes thread might have a different function and capabilities at -273C than at say 30C. it doesn't eat everything it touches until it gets warm.

Who says a creature has to be organized to have intelligence? :shrug:

[Sandi]

I think there are different types of "organisms" in the Oort cloud. Aivas was dedicated to eliminating all of them. I got the impression that the more advanced forms were based on that helium stuff and without it they were essentially dead. I think Edith's take on it is about the same as mine. All that's left after the journey through Pern's atmosphere is basically the "guts" of the things and they just keep on digesting until they collapse.

[ghost8772]

Actually if I remember this right, when they were dissecting the ovoids, they noted that there were several different organisms within, and AIVAS had noted that it was very disorganised. my mind clicked on the Portugese man-of-war idea of a composite organism made up of different creatures. AIVAS had noted that some of the organisms could actually be intelligent but by the time it entered Pern's atmosphere, most of the liquid helium had evaporated, so what was left was the "rude mechanical" thread.

Now about cold weather breaking up thread, Thread running at a minimum a 300 C change, having a temperature difference in lower atmosphere of 30 C really should not make a difference. So there must be something about entering atmosphere itself that would cause that small of a temperature difference to have such a catastrophic effect on the thread filaments.

[Hans]

Still, ghost, it's a 'bookfact' that Thread dies in lower Pernese atmosphere tmperatures and they don't even have to be below freezing (especially not in Todd's books).

So, we'll have to deal with that. Maybe it's something that combines the low temps factor with other parameters, like something in the Pernese atmosphere.

[P'ter]

If they are space entities; then their usual 'atmospheric' pressure would be a fraction of a pascal. Entry into Pernese atmosphere would increase this dramatically. So perhaps, once they've lost their hard outer shell they just implode.

[tatiana]

Originally Posted by ghost8772

Actually if I remember this right, when they were dissecting the ovoids, they noted that there were several different organisms within, and AIVAS had noted that it was very disorganised. my mind clicked on the Portugese man-of-war idea of a composite organism made up of different creatures. AIVAS had noted that some of the organisms could actually be intelligent but by the time it entered Pern's atmosphere, most of the liquid helium had evaporated, so what was left was the "rude mechanical" thread.

Now about cold weather breaking up thread, Thread running at a minimum a 300 C change, having a temperature difference in lower atmosphere of 30 C really should not make a difference. So there must be something about entering atmosphere itself that would cause that small of a temperature difference to have such a catastrophic effect on the thread filaments.

Having just re-read "All the Weyrs of Pern" today, I do recall that Aivas stated that it was the friction of entering Pern's atmosphere that removed the hard shell of the ovoid protecting the thread...with that extreme heat livening up the fungus-like (mycorrhiza) thread, then it would make sense that slightly cooler temperatures could break up the threads -- like how a glass casserole dish that had been cooking for awhile when removed from the hot oven and placed on a cooler, room temperature counter could crack and break. Or at least, that's how I imagine it, 'specially since I did that once, heh.

[T'mynn]

Or removing a VERY ice cold mug from the cooler, putting room tempurature water in it then microwaving it to 200 F. The mug cracked and I cried. It was my favorite mug and I was half asleep.


Atmosphereic rentry tempretures can easily exceed 2000+ degrees F. The thread shell hadn't the advantage of a ceramic heat sheild to protect it as one of our shuttles does. Any intelligant life would've expired within an extremely short time inside it once the shell burned off. This probably happened a mere second after atmospheric entry.

[GinnyStar]

Originally Posted by Emeraldrose

I scanned over Dragonseye and found the reference to the first thread fall that the Weyrs were able to fight mentioned by GinnyStar....It was a PreDawn fall and Late Evening falls are also mentioned...The thread is lumionous in the dark appearing as a banner....The Weyrs also were fighting over snow......so apparently the falls can begin in the darkness but not sure if Late Evening is the latest that thread falls...

Thanks Emeraldrose for the help. I have my good and bad days for reading print.

Right now I just get the missed threads I haven't had time to read or re-read sometime. A

Right now I am listening to audio MP3 CD Dragonheart, a gift from someone over at the NKT from oversea (1 st. MP3 CD for me. / Dragon's Fire was 1 st. on CD for me / Rest on on tape which I well have to replace which I can find the cash)

Here is a few idea for size would the Red Star = How big the path of Thread would be? Watchrider do watch at night as part of job (some book off the top of my head can't recall which one or if in DLGP its comming out of.)
Also Pern's less land and water water,

[GHarris]

Originally Posted by T'mynn

Or removing a VERY ice cold mug from the cooler, putting room tempurature water in it then microwaving it to 200 F. The mug cracked and I cried. It was my favorite mug and I was half asleep.


Atmosphereic rentry tempretures can easily exceed 2000+ degrees F. The thread shell hadn't the advantage of a ceramic heat sheild to protect it as one of our shuttles does. Any intelligant life would've expired within an extremely short time inside it once the shell burned off. This probably happened a mere second after atmospheric entry.

I think the idea is that it does have a very hard shell that can withstand those temperatures, but then when it cools down, it cracks (and releases the lifeform). IIRC, they had to use a diamond blade in AtWoP to open one up.

And it is that unprotected life form that freezes and is susceptible to water.

GH

[T'mynn]

My word, that's a hard shell with a not so pleasent gooey center.
Sorry. <snicker> I couldn't resist that.

I haven't gotten my hands on All the Weyrs of Pern yet. I'll reserve any theories until I've obtained the book.

[Emeraldrose]

The Ovoid captured by the firelizard from space and put in airlock on the Yokahoma (sp)
did not open up and it was definitely stated that the friction of entry into Pern's atmosphere was necessary to release the thread...
We know that there were 2 long intervals because of the two trips with the ship engines
but did the sprinkling of the "zebedees" to kill off the thread in the Oort cloud itself help lower the amount of threadfall?

[Danel]

Well I hate to be posting so much after comeing out of lurkdom, but being an avid poster on Badastronomy web site I think I'll chime in on this one too.

Nightfalls.

The easiest explaination would be that although the red star's never brings in closer to the sun then Pern's orbit, and that it technially releases thread always on the night time of Pern, it takes time for thread to get through the atmospere and then trickle down. The thread oviod hits the tropospere during perns night time, and changes from from the heat into its slowly falling thread state. By the time this form of thread gets to the lower stratosphere, hours have passed, and by the time it's gets to the lower atmosphere where it can be fought, even more hours have passed. So most falls occure during daytime hours.

Other possible explanations. The air is colder on the night side of the planet, and thread freezes in the upper atmosphere without the sun to keep it warmer. Rendering it harmless as Black/Crack Dust.

There are other resons I could think of to support no night falls, but those two sort of leap out at me.

[Hans]

Don't you ever feel bad about posting much! *wags finger*

(especially not after coming out of lurkdom )

[Danel]

Ahhhhhh ahhh! I've been soundly rebuked by the master archivist, however will I recover?

I suspect I'll be sounding off on the science of Pern a lot as topics come up. Being an amateur vulcanologist, I sort of like science. Or maybe I should say I've acquired a taste for it over the years, sort of like for a robust ale.

*edit to add*

Or Benden wine!

[Maleus]

Quite sorry to interfere so late too

Regarding the night falls, I myself always wondered how there could be daily falls at all! And I do since I saw a chart of the Rukbat system in the DLG showing Pern and the Red Star orbits:



OK, the "Pass" mention looks quite wrong, since we know the Red Star just go through the system for a few turns and leaves threads behind. And we know thread falls all turn long, and not only when Pern's orbit cross the Red Star's area.
As you can see, the Red Star is always farther from Rukbat than Pern. Meaning it leaves threads outside Pern's orbit. So, unless there is a very strange spiral falling effect, threads should fall on the dark side of Pern

I had a hypothesis once. Threads left by the Red Star could be attracted to Pern due to gravitation laws within the system (because Pern is the closest massive object?). But once they reach the planet, they would stay all around, like a spherical cloud, going down slowly. Then, when on the day side, some of them, the lowest, would be "pushed" to ground by the solar wind coming from Rukbat. It would explain why threads would "survive" for 50 turns and still fall on Pern regularly only during the day.
Does it worth anything?

[P'ter]

I still think that the diagram is astronomically wrong.

If the Red Star's orbit was transposed to cross INSIDE Pern's, then the daytime only falls would be explained.

[Brenda]

The air is colder on the night side of the planet, and thread freezes in the upper atmosphere without the sun to keep it warmer. Rendering it harmless as Black Dust.

I like this idea.

[Danel]

Originally Posted by P'ter

I still think that the diagram is astronomically wrong.

If the Red Star's orbit was transposed to cross INSIDE Pern's, then the daytime only falls would be explained.

Well, from what I know, objects on a hyperbolic orbit that take them from the Kruiper belt or Oort cloud close to a star, have the most speed as they aproach the point of orbit closest to the star.

In otherwards, an object in a 250 year hyperbolic orbit, would only spend a brief time of that orbit turning around to head back out of the inner system. Like only half year at most. (See Haleys comet, etc..)

So the 50 years of thread fall would not be due the planet being in a close orbit for fifty years, but from thread being depositied close to Pern, and gravity eventualy attracting it over time to fall on the planet.

[ghost8772]

Originally Posted by Danel

Well, from what I know, objects on a hyperbolic orbit that take them from the Kruiper belt or Oort cloud close to a star, have the most speed as they aproach the point of orbit closest to the star.

In otherwards, an object in a 250 year hyperbolic orbit, would only spend a brief time of that orbit turning around to head back out of the inner system. Like only half year at most. (See Haleys comet, etc..)

So the 50 years of thread fall would not be due the planet being in a close orbit for fifty years, but from thread being depositied close to Pern, and gravity eventualy attracting it over time to fall on the planet.

yep, but trying to think through the physics of it. a cometary tail would mean that Pern would have thread when it initially pierced the tail, and the thread would fall for a few weeks at most after. with no rhyme or reason to the fall. Once the red star passed outside Pern's orbit again, then there would be threadfall about once every six months. Again, a steady fall when pern passed through the tail, but probably not the falls Anne described.

[Almaron]

A statement in the DLG states that if Wher eggs hatch away from humans, the young will be wild. Chances are, these wild Whers fly the night falls. In the early years of Pern, less Whers would have meant that Dragons had to fly the falls. Some point after the Third Pass and before the Sixth, Wher information was forgotten. At some point during then, if enough Whers bred in the wild, they could have done the falls, and the Dragonriders just stopped bothering (or they may have decided to leave it to the Whers, but not recorded why, and it got forgotten).

Also, it could be that night falls were originally a lot more common, and the Red Star could have been closer to Pern. If the engines of the colonist starships exploding pushed the Red Star away (and caused the Long Intervals), it could have made night falls less common, and ultimately impossible, as the falling Thread had to fall further or something that made the survival rate drop.

[P'ter]

If there was a trail of thread left behind by the red planet as it closed in on Rukbat, and as it started to head back out, then it could be that the solar wind is the motive force rather than gravity.

[candamyr]

My biggest problem with Thread is: even if the Red Star comes close enough to Pern's orbit to throw Thread at it - the part of its path that wraps around Rukbat (no matter if outside or inside Pern's orbit) takes it 50 turns, hence 50 turns of Thread, while Pern obviously takes 1 turn to turn around Rukbat once...so how can the Red Star be seen equally from everywhere on Pern at all times during the turn? For that matter: how can Thread fall equally (even if a longer cycle of on/off days were reported for the beginning of a Pass, shortening at the peak of a Pass) throughout a turn? If Thread is thread-bent to reach Pern, in the period of a turn, it at least should take shorter to get there while Pern is near the Red Star's location (resulting in a shorter period between falls) and longer while Pern is on the other side of the sun from the Red Star's current location on its path (resulting in a longer period between falls).

I've found this article done for a school project, which states "As it approaches Pern, the Thread-covered planet is captured likely by the gravity of Rukbat, and is pressed into an erratic orbit nearly parallel to that of Pern. It can keep this up for 50 Turns before then shooting back off towards the Oort Cloud."

Would this mean that the Red Star would, for 50 turns, revolve around Rukbat, alongside Pern, until its expelled again and goes on its 200 turn travel? If so, the orbit is likely to be wider at first, tightening towards the peak of the Pass, then widening again until it escapes from complete gravity again - but this would also mean, that it has to be outside of Pern's orbit for the between-fall times to be longer at first, then shortening (and likely lengthening again), which in turn would also mean that Thread only falls on the dark side of Pern...

Unless of course some spiralling action someone else mentioned comes into effect, maybe driven by solar winds, magentic fields or whatnot, plus the Thread's need to be in the warmth - and they end up on the sunny side eventually, spores popping open and Thread falling...and like sperm, those that make it to the sunny side have a chance to burrow, those that remain on the dark side die...

*scratches head* nothing makes sense...so as stated before, we have to apply the BASS rule?

[Kath]

*puts on doctoral bonnet*

I'm going to rearrange your post mercilessly to try and build up a clear picture and answer your questions at the same time.

Originally Posted by candamyr

I've found this article done for a school project, which states "As it approaches Pern, the Thread-covered planet is captured likely by the gravity of Rukbat, and is pressed into an erratic orbit nearly parallel to that of Pern. It can keep this up for 50 Turns before then shooting back off towards the Oort Cloud."

An interesting idea, but not plausible. It won't work in practise, and the simplest physical explanation works fine.

Would this mean that the Red Star would, for 50 turns, revolve around Rukbat, alongside Pern, until its expelled again and goes on its 200 turn travel? If so, the orbit is likely to be wider at first, tightening towards the peak of the Pass, then widening again until it escapes from complete gravity again - but this would also mean, that it has to be outside of Pern's orbit for the between-fall times to be longer at first, then shortening (and likely lengthening again), which in turn would also mean that Thread only falls on the dark side of Pern...

No.

The laws of physics mean that the Red Star will orbit Rukbat in an ellipse, with Rukbat itself in one of the two 'foci' of the ellipse. (Google 'ellipse+foci' if you want to look at an appropriate diagram.) Because of how elliptical orbits work, the Red Star (RS for short) will move fastest when it's closest to Rukbat, and slowest when it's far away. This is why the RS grows dramatically in brightness before the Pass starts - it's moved out of the Oort cloud, where it spends most of its time.

And here we have Fandom Misconception #1. Don't worry, you're in good and plentiful company.

Originally Posted by candamyr

My biggest problem with Thread is: even if the Red Star comes close enough to Pern's orbit to throw Thread at it - the part of its path that wraps around Rukbat (no matter if outside or inside Pern's orbit) takes it 50 turns, hence 50 turns of Thread, while Pern obviously takes 1 turn to turn around Rukbat once...so how can the Red Star be seen equally from everywhere on Pern at all times during the turn? For that matter: how can Thread fall equally (even if a longer cycle of on/off days were reported for the beginning of a Pass, shortening at the peak of a Pass) throughout a turn? If Thread is thread-bent to reach Pern, in the period of a turn, it at least should take shorter to get there while Pern is near the Red Star's location (resulting in a shorter period between falls) and longer while Pern is on the other side of the sun from the Red Star's current location on its path (resulting in a longer period between falls).

The RS does not spend 50 turns in the vicinity of Pern.
It doesn't even spend 50 Turns in the inner part of the Rukbat system.

The simple laws of orbital mechanics, and the dimensions of a planetary system, mean that the RS will inevitably be in and out of the visible system within a decade or so.

The RS will also not be seen equally bright at all times of the year. Depending on its placement in the sky, some parts of the planet won't see it at all. We know that its orbit is such that it approaches more or less from the sun-ward direction in the Northern Hemisphere winter, and that its orbit lies pretty much in the same plane as Pern's orbit, rather than diving through it at a steep angle. Before the Pass starts, it'll be a nighttime object in summer and a dawn/dusk/day object in winter -- for the northern hemisphere. Reverse things for the south.

The Pass starts when the RS crosses Pern's orbit and moves into the inner system. At this point, it is dragging a whole shitload of thread spores with it. The RS doesn't stick around close to Pern, but the spores do.

The RS will heat up, produce gaseous eruptions, have its atmosphere disturbed by the sloar wind, and all those spores it carries along with it will get tossed away as it goes, pulled out of the RS's own influence by the gravitational disturbance of other objects. There's enough of it that the whole inner system will become thick with debris. Not ideal physics, but it's the best we've got.

Pern moves through this debris-field of thread spores. Pern rotates. The bunches of Thread that the planet intersects will all take roughly the same time to fall to ground, and this way you can get Thread falling in bunches, landing preferentially in the daytime, and hitting all parts of Pern equally, more or less.

What does the RS look like during a Pass? Well, for the first year it'll behave a lot like a REALLY bright Venus. After that, a REALLY bright Jupiter. And then like a fading comet - it'll slowly take on a more or less fixed position relative to the background stars and fade in brightness by the time the Pass is half-way done. It'll be somewhere similar to where it was first spotted, offset by maybe a few tens of degrees in the sky, but more or less accurately you can say that once again it'd be a summer nighttime object in the Northern hemisphere/winter night in the south, lying close to the equatorial plane - it'll be highest overhead near the equator, but not get high above the horizon at higher latitudes.

[Kath]

Originally Posted by P'ter

If there was a trail of thread left behind by the red planet as it closed in on Rukbat, and as it started to head back out, then it could be that the solar wind is the motive force rather than gravity.

Yes. THis is perhaps the best argument I've ever seen. RS dumps the Threads close to Rukbat, when it gets heated the most, and Rukbat drives them back out again in an orderly fashion.

And again, echoing what others have said, the RS will do that first passage of the innermost part of the system in under a Turn.