Traveller Ringworld

[roygbiv]

Originally posted by Tom Kalbfus:
This loop of cable has no angular momentum since its not rotating. the only angular momentum is in the part of the ring world that is rotating. I can see that your pride won't allow you to conseed a single point,

No, I will concede this point.

Actually, I have been visualizing this construct incorrectly. Your ring is not pulled rigid, but "pressed" rigid by the gravitational attraction of the star's center of mass. I think I'm starting to see what you're getting at.

I think your description of the base unit of construction as a cable is also a little misleading. Cables aren't meant to be compressed through their vertical axis; they're designed to withstand "stretch" along their vertical axis. They provide structural support by pulling on other objects or against each other, but that doesn't seem to be what you're trying to do here and that's why I confused gravity and angular momentum in your model. In effect, you're bulding an arch, except your arch will span 360 degrees. So you don't need cables, rather you need trusses, or some combination of the two.

Now that I've conceded this point, will you at least address my assertion that your ringworld posits as much super-science (making gigantic cables from a stellar acretion disk, creating a maglev train the length of one earth orbit, powering that maglev with only solar power--all you've offered so far...) and that it's only your preference for your vision that sets it apart from Niven's design?

 

[roygbiv]

Originally posted by Tom Kalbfus:
So, that's an engineering problem.

So that's your answer for every objection.

There is no substance on the chemical periodic table that has the properties of scrith.

Tell me, Tom. Do you allow bonded superdense hulls in YTU? Scrith seems like a straight line extrapolation from them.

I believe it to be possible while Niven's ring world may or may not be.

That's just it: you're defending your beliefs. You believe that steel cables, several miles thick and thousands of miles long will behave in a vacuum approximately as their miniscule cousins still do on earth. You believe that it will be possible to extract all the materials you need by skimming a planetary accretion disk. You believe that it's possible to build a maglev train as long as one earth's orbit. You believe that the stellar output available to you will be sufficient to power that train. You believe, etc., etc.

Niven makes several fantastic concessions and his biggest is that nuclear manipulation of matter is possible (which is why Pak can turn hydrogen into scrith). He bothered to work out the math, however, which makes his model more credible to me. His ringworld, being a rigid band, is less complicated and less prone to catastrophic failure than yours is, simply because it has no mechanical joints.

You make a greater number of fantastic concessions and handwave everything else away. You've been arguing for a more complicated, more error-prone construction simply because you don't like the idea of scrith.

Finally, your ringworld model is not consistent with the OTU. You're going out on a limb and insisting that everyone follow you, but you haven't given me enough reason to go.

 

[savage]

So the new idea is a bridge around a star?

Alright leaving an asteroid belt bad idea. Similar mass Gas Giants equal distant around the same orbit should be fine. Ringworld needs material for repairs unless it plans on eating itself. I don't think anyone wants to wait 100 yrs...and when the repair material shows up it throws off the ring. Heck the ring world manufacturing planet would need to be bigger than earth.

Dust versus planets is easier?? So you have a magic machine collecting dust versus a magical machine moving and breaking planets...I'll take the planets. If I find iron and need iron I can use the iron instead of making everything.

We are talking about Traveller right! well just use the magic of anti-gravitic plates and any space faring race can use their hull material to build a ringworld.

Savage

 

[TKalbfus]

Now that I've conceded this point, will you at least address my assertion that your ringworld posits as much super-science (making gigantic cables from a stellar acretion disk, creating a maglev train the length of one earth orbit, powering that maglev with only solar power--all you've offered so far...) and that it's only your preference for your vision that sets it apart from Niven's design?

Ok here's my model: You have an inner ring that rotates and an outer ring that does not. The inner ring levitates off the inside of the outer ring. The outer ring is not so much a cable as a band of metal 1,000,000 miles wide, some 50 miles thick and in completely shadowed by the inner ring. Since the outer ring receives no sunlight it gets very cold, so cold in fact that it becomes superconducting. The inner ring generates a magnetic field that is reflected by the superconducting outer ring. Like magnetic poles repell each other so the outer ring repells the inner ring and their is no contact between the two. This is fairly simple. The outer ring does not need to be refrigerated to stay cold, in the vacuum of space, all it needs to do is stay out of the sunlight. Running a current through the bottom of the inner ring should generate a magentic field around the inner ring, the bottom of the inner ring should be faily cold as well and could be superconducting, which means there is no electrical resistance for the current running through the bottom of the inner ring. Very little energy input is required to maintain this system. No exotic physics is required. I'm not insisting that everyone follow this model, my only point is to show that the technology to build this thing is not as high as you think. With self reproducing robotic factories, or nanotechnology it is doable, despite its huge scale. I don't know how to make the nanotechnology or the self reproducing robotic factories, but if I could describe the futuristic technology exactly I would patent it. And why exactly do you think mining a dust cloud is so impossible? It requires some scoops, much like those on interstellar ramjets.
Now grav technology to blow up planets would obsolete a ring world, so I'm assuming that ringworld builders don't have this technology. FTL technology would make the ringworld pointless, so I not assuming they have this technology either. I don't think a ringworld is TL21. Grav technology comes fairly early in Traveller so the ringworld has to be at a tech level less than that.

 

[savage]

I'm not seeing the advantage you'll need more material than in the Sol system. After Dysans Sphere came out Niven wanted a simpler solution. The sphere would require more material than Sol provides. So does your solution. If we're going to leave that basic behind all of the other can also be dumped.

anti-gravitics/gravitics science fantasy is a part of traveller. Some refs dump it based our present technology beliefs. But it doesn't completely remove the reason of a ring. It changes how it would function in traveller. You still have reasons to rotate the ring, and you still need heat and light. Actually, Niven's inner ring with solar arrays could probably provide infinite power to the ring... the gravitics might only be adequate to replace the jets improving safety.

Savage

 

[TKalbfus]

I'm not seeing the advantage you'll need more material than in the Sol system. After Dysans Sphere came out Niven wanted a simpler solution. The sphere would require more material than Sol provides. So does your solution. If we're going to leave that basic behind all of the other can also be dumped.

The Solar System doesn't provide any scrith however. If you have the technology to transute Hydrogen into scrith then Larry Niven's ringworld would make sense, but if you don't have that technology you build something like my ringworld. I have nothing against Niven's design, all I'm saying is that it represents a higher tech level than my version of the ringworld. A ringworld would have to be TL8 if it were to fit in with the Traveller Technological tables. Grav vehicles appear at TL10 while air/rafts appear at TL8. My guess is that a TL8 air/raft is supported by ducted fans or jets and can only operate in a thin atmosphere or greater, while a TL10 air/raft uses grav units and can operate in a vacuum. The jump drive gets discovered at TL9. Personally I think FTL comes too early in Traveller. I like there to be civilizations that spend a long time at TL8 and early TL9 that build things like ringworlds and interstellar ramjets. I think its a mistake to make a ringworld into a super artifact of TL21+ that's beyond the ken of mere mortal humans. I don't want to have to many techno-deities running around in my Traveller universe. No 'Q's in other words. Therefore I prefer to build my ringworld with a minimum of techno magic and its an interesting challenge to see how one can be built with real materials.

Thw Wright Brothers airplane came before jets. Airplanes and helicopters should come before grav vehicles and slower than light star ships should come before FTL star ships. My ringworld is a more primitive version of Niven's ringworld as such it requires more material that our Solar System can provide, but their are other solar systems that have more material to start with, and its best to catch them before the are fully formed and before all that material becomes locked away inside planets and stars. I don't like this "ego-thing" that I have going with the other guy who seems determined to knock down this idea, perhaps because he didn't think of it. I don't care, I don't think of this as a contest between competing ideas where the winner gets a trophy or something. I just want to provide a good idea that everybody can use.

 

[savage]

I'm certainly not in the "beat up Tom category". I'm not certain anyone else is either based on past readings...and I've certainly agreed with you on other threads.

There has been some confusion and always different view points. I've directed mine towards engineering process not mathmatics or physics...
What is easier to build? Will it last and be safe for billions? (Niven's really didn't), and is it economically feasible.
Niven used Sol for his math calculations because it was his only and best example. Your non-FTL race would be darn lucky to find a better solar system within a short distance that makes this feasible. I would be far from disagreeing with the possibility and I too think FTL jump drive is discovered a bit early in the average world.

Its just a suggestion but...why don't you put together your thoughts on an alternate ringworld, do the math, put it in a whitepaper with graphics and see what feedback you get. It can only help to improve your idea into the theoretical.

The main comment I had for everyone is that a well designed ringworld would provide resources (perhaps alternates) that would allow a race to regrow after a disaster and change directions when growing normally. A resource starved/ high maintenance env. is a bad thing.

There are many alternate possibilities to a race using the ringworld, as I tried to point out. I like the lowtech theory. Perhaps it took them 10,000,000,000 years to reach TL8. Its a practical direction for them. Perhaps their in the empty sector and space is limited. They need to make the best use of all of it. And with their attentions on building RW their research on FTL is extremely underfunded. I also like the TL21+ superartifact with scrith (perhaps a fancy word for Traveller superdense). Don't really go into the ancients grandfather did everything that was cool philosophy. Saying that I am a big fan of the Krell. This is a good Krell project.

About this space dust thing. How does the TL8 world turn it into iron, copper, water, grass, and air?

Savage

 

[roygbiv]

EDITED

Originally posted by Tom Kalbfus:
The outer ring is not so much a cable as a band of metal 1,000,000 miles wide, some 50 miles thick and in completely shadowed by the inner ring. Since the outer ring receives no sunlight it gets very cold, so cold in fact that it becomes superconducting...

I typed up quite a long refutation of your model, which I'm not sure if you've seen or not, but I'm now thinking better of it.

I wasn't trying to make this discussion personal, Tom and I'm sorry if you felt that you were being attacked.

 

[GBoyett]

Hey Guys...

This topic has actually got me doing two things:

1. Bought a new copy of the Ringworld Trilogy. I'm currently 1/3 thru RW.

2. I'm developing a Traveller adventure around a starship crew accidently finding a Pocket Universe with a RW! This adventure is going to be a Bar Mitzah gift to a friend's son in September.

 

[roygbiv]

EDITED: Felt that this was directed too strongly at Tom. Not trying to make this personal, just agreeing to disagree

Originally posted by Savage:
I would be far from disagreeing with the possibility and I too think FTL jump drive is discovered a bit early in the average world.

I think this assumption that jump/FTL discovery is linked with technological progression is a fault of Traveller tech tables which show almost a straight line development across the board.

There can be a hundred plausible reasons why a system develops technology far in advance of the Imperium and yet never develops interstellar capability.

What if that system had been passing through a "gravity wave" (say from a nearby neutron star) for several millenia which caused every ship which attempted jump to precipitate out of J-space one week later and in exactly the same spot? I could see that nascent jump technology would be attempted for, say a few hundred years, and then abandoned as impossible. You don't even need a gravity wave: some quirk of the planetary system could be causing this precipitation. Maybe there's something unusual about the primary star: maybe it exherts some peculiarly strong tidal forces which screw up the local n-space/j-space junction.

With nothing else to occupy their time, and with a survival imperative because of system overcrowding, an intelligent race may develop fantastic levels of tech in some areas (bioengineering, gravitics, nuclear materials manipulation) but lag completely in others.

Factor in social and historical pressures as well: we can make cars that run for 100 years, but no automaker is going to do that...

There are many alternate possibilities to a race using the ringworld, as I tried to point out. I like the lowtech theory. Perhaps it took them 10,000,000,000 years to reach TL8.

I don't think that a race can build a ringworld at TL 8. Just building the orbital manufacturing facilities to produce Tom's superconducting band would present an insurmountable challenge. You couldn't use steel or molybdenum or any other "common" element without some serious re-working. This discussion hasn't veered into the realm of what happens to metals which are exposed to vacuum, interstellar dust and hard gamma radiation for millenia. Any race which could attempt this, whether they've achieved jump or not, is going to be fantastic at manipulating elements at the nuclear level.

And some superspecies of VonNeumann machines is just as much a handwave as scrith. Nanotech is almost non-existent in Traveller, and certainly doesn't appear at TL 8.

Its a practical direction for them. Perhaps their in the empty sector and space is limited. They need to make the best use of all of it.

The thing is, they could, using TL 8-9 technology to pull Kuiper body objects into the inner system and hollowing them out to use as living space. They could make a trip out to the Oort cloud and drag iceball comets back insystem to use for water, organics and other volatiles. I think a truly crowded, pre-interstellar system is going to look more like Glisten. They're going to be too busy trying to survive to cannibalize their system to build a ringworld that they don't need. (ever read The Mote in God's Eye?)

I agree with, was it ninthcouncil, or maddog, that the ringworld would be built as a folly. Something gratuitous, designed by a society who has all the tech, all the time and no pressing need other than curiosity. It was probably an Ancient thought experiment: maybe one of those parties that just got carried away.

We can postulate all we like, but the Leenitakot ringworld was built by the Ancients. Like it or not, the Ancients had either jump or some form of FTL capability. The fact that Leenitakot has an unfinished ringworld suggests that it was a kind of experiment, attempted then abandoned, instead of some desperately needed housing project.

Of course, you can put whatever you want IYTU.

 

[roygbiv]

Originally posted by George Boyett:

2. I'm developing a Traveller adventure around a starship crew accidently finding a Pocket Universe with a RW! This adventure is going to be a Bar Mitzah gift to a friend's son in September.

Please post it here, or somewhere on the web, when you're done!

I'm always looking to stea...ahem acquire good adventure ideas.

 

[GBoyett]

Originally posted by roygbiv:
</font><blockquote>quote:</font><hr />Originally posted by George Boyett:

2. I'm developing a Traveller adventure around a starship crew accidently finding a Pocket Universe with a RW! This adventure is going to be a Bar Mitzah gift to a friend's son in September.

Please post it here, or somewhere on the web, when you're done!

I'm always looking to stea...ahem acquire good adventure ideas. </font>[/QUOTE]I'm planning to release/publish it.

Here is a small sneak preview.

The RW pocket universe is found in the Spinward Marches. Exact location is in the Abyss found in Vilis, Lanth, and Lunion subsectors. GT:Behind the Claw Pg 90 mentioned stories of starships disappearing in the area, which is something I played with long before GT.

I think you get the general Idea.

 

[Zutroi]

For the major gearhead to consider:

As long as you require attitude jets, they can also serve to reduce the stresses experienced by the RW. Not enough to avoid scrith or Tom's superconducting maglev system, I'm sure, but with enough of them it could make a small dent...

Also, I believe Tom's mention of 'reflecting' the magnetic field is in fact a reference to the well-known phenom of dropping a magnet onto a superconducting surface. The magnet stops and just floats there, as long as the superconductive state persists. This method is obscenely simple to implement and has been chosen by several serious maglev demonstration projects as it completely eliminates the need for active feedback controls on the levitation system.

 

[roygbiv]

Originally posted by Zutroi:
For the major gearhead to consider:

From the way you present that, you make it sound like a bad thing.

I've reconsidered my position and removed one of my responses. I may have been getting a bit too strident. It's Tom's TU, afterall.

Also, I believe Tom's mention of 'reflecting' the magnetic field is in fact a reference to the well-known phenom of dropping a magnet onto a superconducting surface.

I'd never heard it referred to that way. Thanks.

Tom, if you saw that post before I edited it, I'm sorry I jumped on that so hard.

 

[mad13142000]

One would think that a civilization with grav technology would use that in place of magnetic attraction...
Some well placed grav plates would act like the weird 'structural integrety field' thingy from Star Trek...(not that I'm advocating ST here) and help keep it together better than superconductors...
I still see no way to keep it stable without big engines (bussard ramjets or some other big rocket)

Just a thought
-MADDog

 

[savage]

Tom, Hope you'll take my suggestion on white papering seriously. As redefined by some of the others I think I'm getting the drift. Interesting.
Specifically if you go for low tech. Perhaps TL9 is better. Space planes, stations, and other features make it a little easier to implement.

Still not buying into the Dust cloud if its low tech. blow up the planets.

This is not necessarily a folly. A race that prefers unity, achievements for ego, or has significant space problems from overpopulation. Perhaps reproduction is not a choice but a necessity to survive. A ring world allows them a new location to blossom. Your candidate might be in a small cluster of 2-3 stars within a parsec but without FTL and habitable worlds. RW brings out several advantages, free solar power, safety, racial unity, and strength.

I'd say there are a few of these floating about.
I'm sure that if we could build one we would just to do it.

Savage

 

[TKalbfus]

Its just a suggestion but...why don't you put together your thoughts on an alternate ringworld, do the math, put it in a whitepaper with graphics and see what feedback you get. It can only help to improve your idea into the theoretical.

Sounds like a good idea. My ringworld is 1,000,000 miles wide or 1,600,000 km wide. 1 AU in radius, it can either be made of some super material or use an engineering workaround to hold it together while it spins. The ringworld will have a floor and on top of that 1 to 20 km of rock, dirt, soil, and water. I think a mechanical Von Neuman system of robots and factories is a good way to build and maintain it. the robots individually will be very specialized and not very bright, their are many different robot types however and like a colony of ants, or a hive of bees they all work together towards a common goal of constructing and maintaining the ringworld. The ringworld floors and walls are made of some kind of smart material, a limited form of nanotech that works with only one type of material and allows the ringworld floors and walls to heal damage done to them over time, much like a creature heals its wounds. On the vacuum side of the rim walls the ringworld floor continues some distance and is covered with automated Von Neuman factories staffed by robots. The robots constantly repair and rework the factories and the ringworld itself. There is an intelligence behind all this, but it is a machine intelligence that is uncreative and only acts according to its specific programming, which is to repair and maintain the ringworld and to send out its starships to collect organic species from a variety of different compatible worlds.
The ringworld is basically a zoo. All the creatures live under 1-G, a standard or thin atmosphere. The day length is around 25 hours and there are seasons accomplished by varying the daylength and regulating the light that gets through the shadow ring.
I was thinking about how Niven achieved night and day, and it occured to me, that nights on his ringworld didn't get very dark. The ringworld band has a width the same as the diameter of the sun and the whole thing is visible as an arch over the sky and the sun, day and night. The arch should illuminate the night more brightly than a full moon on Earth and only the brightest stars would be visible in the night sky, or more likely none at all. Instead of having shadow squares, the shadow ring is composed of a series of shutters that open and close. When the shutters close the entire ringworld experiences night at once, there is no arch in the sky, only a black silloette set against the starry sky. Nights are dark and moonless. The entire ringworld experiences seasons winter, spring, summer, and fall. Each season lasts 90 days. There are climatic regions ranging from Artic to Tropical. This is done by varying the altitude of the various land features. The lowest parts of the ringworld are tropical, the winters never fall below freezing although they are cool, spring and fall are warmer, and the summer is hot. The temperate zones are like the temperate zones on Earth except that the sun is always directly over head. The temperate zones are higher than the tropics and they have their own temparate oceans at a higher altitude than the tropical oceans. Water is circulated between the tropical and temparate oceans by a series of locks and canals. Water is pumped uphill from the tropical oceans to the temperate oceans and is allowed to flow down hill in vast salt water rivers leading back to the tropical oceans. Winter has snow, and spring, summer, and fall are what we would expect. This climatic variation allows for migratory species. Subartic and artic climes are done a similar way. All these climate zones are located within 10,000 miles of each other from any location on the ringworld to allow for seasonal species migration.

 

[jrients]

I think a mechanical Von Neuman system of robots and factories is a good way to build and maintain it. the robots individually will be very specialized and not very bright, their are many different robot types however and like a colony of ants, or a hive of bees they all work together towards a common goal of constructing and maintaining the ringworld.

It would be great if adventurers visiting your ringworld actually mistook these creatures for local insectoids.

 

[Zutroi]

Originally posted by roygbiv:
</font><blockquote>quote:</font><hr />Originally posted by Zutroi:
For the major gearhead to consider:

From the way you present that, you make it sound like a bad thing.

</font>[/QUOTE]Not at all!

Signed - Dr. Zutroi, Emeritus Professor, Regina Institute for Gearheading.

 

[TKalbfus]

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I think a mechanical Von Neuman system of robots and factories is a good way to build and maintain it. the robots individually will be very specialized and not very bright, their are many different robot types however and like a colony of ants, or a hive of bees they all work together towards a common goal of constructing and maintaining the ringworld.
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It would be great if adventurers visiting your ringworld actually mistook these creatures for local insectoids.

The most likely response if PCs attacked the robots would be that they robots would be destroyed as they were not designed for battle. The local ringworld sector computer would make a note of the loss of this robot and immedately order a replacement and a decoy to be constructed. The decoy would show up first at the location where the first robot was destroyed, it looks like that destroyed robot except that's its armored and carries a laser cannon on a pop-up turret. If the decoy is attacked it will fight back at attempt to destroy the attacker. Once the local sector computer is sure that they attacker is destroyed, it will send the true replacement robot and a recycler to collect the damaged robot debris.