Ringworld (CT type)

[inexorabletash]

Maybe those extra belts in known space aren't from the Final War, but what is left after you suck the iron core out of an Earth-sized planet through a pocket universe portal and to the megastructure construction zone.

Maybe one of these "mining" portals got left behind in the core of a now-inhabited world.

Maybe it suddenly activates.

 

[Blue Ghost]

Wow, there's a thought. Maybe the material was imported from ANOTHER universe. Hmm...

 

[Chuck Anumia]

My Thoughts

Some thoughts;

One of my biggest beefs with Ringworld or like concepts is getting rid of heat. The reason life works on earth is because the earth spins. This function does two things; it turns the hot side away from the heat source so that it can cool down and dump heat into space, and also generates the magnetic field that protects us from other radiation.

How do you do that with a ringworld?

Just me.

The Material a ringworld is made from (unobtainium or whatever) is superconductive and can be used to transfer heat from one surface (that facing the sun) to the back side (towards space).
ALSO:
The Heat is used to generate power for the ENTIRE ring and the inhabitants of it.
There could be (as suggested elsewhere) be sections of screening (space solar sails or other) rotating at a different rate than the ring to absorb some of the radiation and provide shadow times on the surface of the world.
I am unsure as to how deep the material on the world needs to be to sustain life (1/2 KM? 1 KM? 5 KMs?)
Perhaps the walls are in place and the world simply needs filling and atmosphere?
Or the walls are laying on the surface and need to be raised?
These must come from asteroids, uninhabited and vacuum worlds and gas giants in other parts of space or perhaps a different dimension or parallel universe?
Advance technical devices (handwavium) may (most likely will) need to be used to transport the materials to their final destination.
Why create and inhabit a ringworld?
1. Centralize government over a singular space.
2. Control the use of materials and technology in a central place.
3. Create a habitat for a singular species
4. Create a centralized point for gathering military power to use elsewhere.

 

[aramis]

You can get reasonable sustained farming in under 1m of topsoil - it's being done on rooftops in NYC, Detroit, and Tokyo. It does require some inputs. In the Mat-Su valley, Many of the farms have under 2m before you hit permafrost; that permafrost, for farming purposes, is equivalent to waterproof bedrock.

to use 1G spin "grav" to maintain an atmosphere that people can breathe is at least 50km sidewalls. To maintain earth-standard atmosphere at same 1G, you're looking at least 100m. Really, you want about 500 km for safety' sake, and you NEED the occasional baffle to keep the air moving. Even with baffles, unless they cross the whole width, you're going to have a steady wind out of spinward at altitude. Creative baffling can produce interesting effects - like a sideways wind. Maps of real worlds are going to suffer from abnormal winds for their topology, so should fail to resemble their models fairly quickly. (Niven is aware of this, and handwaves it somewhat in RWE and RWT.)

Niven used something like 100m of dirt on most of the ringworld, and about 1km of foamed scrith beneath, IIRC. Wait - looking in the Ringworld RPG.

Scrith is an unreasonably strong material, virtually indestructible, and much denser than lead. It is the brute matter of all fundamental construction on Ringworld. Beneath fifty feet of soil, there is bedrock; and beneath the bedrock is a wall of impenetrable scrith. The floor of the Ring is made of solid scrith, everywhere at least fifty to a hundred feet thick. Beyond this structural foundation is up to a kilometer of foamed scrith meteor shielding; and beyond that only the vacuum of space.

327,000.'	100km	Air
50'	15.3m	Soil
50'-100'	15.3m-30.6m	bedrock*
50'-100	15.3m-30.6m	Solid Scrith
3270'	1000m	foamed Scrith

[tc=3]Niven's Layer Cake[/tc] [tc=3] bold indicates sourced from above quote [/tc]

So, we're looking at stuff with a specific gravity of about 30+... it's collapsium of some form.

 

[Blue Ghost]

A crap-load of robots would cost a butt-load of money. The Traveller paradigm does not accomodate von Neumann machines (not at TL15 anyway). So each and every robot has to be bought and paid for, gets worn out and has to be repaired occasionally and eventually replaced. Building a ringworld at TL15 would cost a LOT. Far more than practical. Or so I suspect. I admit I can't prove it.


Hans

I think it's doable. So there

 

[rancke]

I think it's doable. So there

Ah, but do you believe it's doable because you've made some reasonable assumptions and back of the envelope calculations that show that it's possible or just because?


Hans

 

[Blue Ghost]

Another thing to think about, there are other solar masses than our own sun. Cruising through the archive I came across an old post from signless;

signless signless is offline
Citizen: SOC-12

While most of us here are intelligent (and imaginative) enough to envision the grand scales involved in our fair game...a little visual illustration never hurts.
I found the following, while not exactly crystal clear, at least interesting enough to give me pause for a "holy cr*p" moment.

http://www.rense.com/general72/size.htm

And, I seem to recall someone posted this link a few years back from Youtube;

https://www.youtube.com/watch?v=HEheh1BH34Q

The point here being that if you can come across one of these things, then there may be a system that has several gas giants, or mini gas giants and other bodies to mine and shape.

I think this can solve the material needed portion of the equation. I'll bow out of the discussion right now, and let you other folks hash out the physics and feasibility.

 

[Blue Ghost]

Ah, but do you believe it's doable because you've made some reasonable assumptions and back of the envelope calculations that show that it's possible or just because?


Hans

A little bit of A and a little bit of B.

I just think that for all of Traveller's desire to balance chemical equations and make sure the physics and other math works, that there comes a time when you have to think about your players; your audience, and say "Wow, that would be cool if.......", and then take your friends and players through a really rockin' game.

It's like writing a great story, or making a great film. You as the ref are there to entertain. You as the player are there to have fun. Otherwise what's the whole point?

Behold, a fusion of properties; The Doctor on the HALO ringworld.

 

[aramis]

A little bit of A and a little bit of B.

I just think that for all of Traveller's desire to balance chemical equations and make sure the physics and other math works, that there comes a time when you have to think about your players; your audience, and say "Wow, that would be cool if.......", and then take your friends and players through a really rockin' game.

Many of us reject "Just because it's cool" as a good reason. Some of us reject it as a reason, period.

 

[Highorbit_drifter]

Many of us reject "Just because it's cool" as a good reason. Some of us reject it as a reason, period.

I dunno... That sounds an awful lot like Nick Sohl's argument with Lucas Garner about abstract knowledge in Protector.

At a wild guess TL15 could build a ringworld; at huge and probably ruinous expense. Its more likely than the ESA building STL colony ships in 2050. But it does rely on transmutation on an industrial scale - possible I suppose at Traveller TL15 but discouraged in canon. If black globe generators are just becoming available, there is some understanding of force fields. Maybe microscopic chains of them... Very unstable and practically begging to be destroyed in a cataclysmic flash. TL 16 or 17 is much more likely, but probably nearly as vulnerable.

Isn't a ringworld unstable? What keeps Grandfather's old ringworld from smashing into its sun?

 

[aramis]

I dunno... That sounds an awful lot like Nick Sohl's argument with Lucas Garner about abstract knowledge in Protector.

At a wild guess TL15 could build a ringworld; at huge and probably ruinous expense. Its more likely than the ESA building STL colony ships in 2050. But it does rely on transmutation on an industrial scale - possible I suppose at Traveller TL15 but discouraged in canon. If black globe generators are just becoming available, there is some understanding of force fields. Maybe microscopic chains of them... Very unstable and practically begging to be destroyed in a cataclysmic flash. TL 16 or 17 is much more likely, but probably nearly as vulnerable.

Isn't a ringworld unstable? What keeps Grandfather's old ringworld from smashing into its sun?

Niven's math shows it stable for 3+ millenia, depending upon the star's stability. But once it goes off-center, gravity will pull it further off center.

Niven solves this in RWE by adding the ramscoop drives around the rim.

Grandfather could solve this with gravitics rather than ramscoops. This has a side benefit of not speeding up the spin. This could even be automated easily.

 

[Blue Ghost]

Niven's math shows it stable for 3+ millenia, depending upon the star's stability. But once it goes off-center, gravity will pull it further off center.

Niven solves this in RWE by adding the ramscoop drives around the rim.

Grandfather could solve this with gravitics rather than ramscoops. This has a side benefit of not speeding up the spin. This could even be automated easily.

Which is kind of the thrust of my "coolness" argument. Wouldn't it be cool if we had, oh, say, jump drive? But we don't, yet it's a convention of the game. Ringworlds are fairly high tech, probably moreso than a lot of other structural engineering feats, but that doesn't take away from the "boy, what if..." factor.

Admittedly ringworlds are kind of pushing the exception to the "boy, what if..." clause. However, to me that's the stuff dreams are made of. But, to each his own.

 

[whulorigan]

I just think that for all of Traveller's desire to balance chemical equations and make sure the physics and other math works, that there comes a time when you have to think about your players; your audience, and say "Wow, that would be cool if.......", and then take your friends and players through a really rockin' game.

Ironically, (and echoing Mike Wightman from another thread about TL), I think that in order to be "believable", the higher TL something is, the less "concretely explainable" in hard-science terms it should be. Things which are "near future" (i.e Late TL8 thru TL9) should be extensions of (or developments of) rock-solid hard-science (possibly a single "breakthrough" [such as contragravity], but no more).

As one moves up the TL chart, the hard-science explainability should be gradually relaxed as the TL increases, in order to be a believable vision of future technology. At some point you begin running into the Arthur C. Clarke effect where technology has become sufficiently advanced that it is almost like magic.

For a Ringworld (which Traveller canon places around TL25-27), we are 10-12 TLs beyond the Imperial maximum of TL 15 (which should itself be mind-bogglingly advanced compared to us today at roughly TL8). A ringworld of the type built by the Ancients will have been accomplished with technology and scientific understanding that we really cannot even begin to analyze from a TL8 perspective. Remember, the substance Monadium found by Imperial Scientists on Antiquity has completely defeated all scientific attempts to analyze, break, or penetrate with TL15 technology. The best they can do is hazard a guess that it might contain titanium.

 

[mike wightman]

Too little is made of the TL12 breakthrough technology - the nuclear damper.

It allows for control of the strong and weak nuclear forces. Couple this with gravitics and cheap fusion power and transmutation of heavy elements becomes totally plausible.

Bonded superdense armour (TL14) already collapses the electronic structure (interesting quantum engineering achievement) which is then strengthened by some sort of energy input (note the type of energy isn't given).

Even less is made of the most magical technology of all - acceleration compensation fields.

Build your ringworld and use acceleration compensation field technology to reduce the stresses on the bonded superdense metal that has been made by the mass transmutation of matter mined from the system.

High TL engineering in the OTU should be magical to us if it is making use of these types of technology.

My money is still on it being a dormant device to pinch off a pocket universe

 

[Blue Ghost]

Ironically, (and echoing Mike Wightman from another thread about TL), I think that in order to be "believable", the higher TL something is, the less "concretely explainable" in hard-science terms it should be. Things which are "near future' (i.e Late TL8 thru TL9) should be extensions of (or developments of) rock-solid hard-science (possibly a single "breakthrough" [such as contragravity], but no more).

As one moves up the TL chart, the hard-science explainability should be gradually relaxed as the TL increases, in order to be a believable vision of future technology. At some point you begin running into the Arthur C. Clarke effect where technology has become sufficiently advanced that it is almost like magic.

For a Ringworld (which Traveller canon places around TL25-27), we are 10-12 TLs beyond the Imperial maximum of TL 15 (which should itself be mind-bogglingly advanced compared to us today at roughly TL8). A ringworld of the type built by the Ancients will have been accomplished with technology and scientific understanding that we really cannot even begin to analyze from a TL8 perspective. Remember, the substance Monadium found by Imperial Scientists on Antiquity has completely defeated all scientific attempts to analyze, break, or penetrate with TL15 technology. The best they can do is hazard a guess that it might contain titanium.

I think that's a key observation. A technology paradigm that's always struck me is the sword and spear advances through the ages. The basic design of the sword hasn't changed, nor has the spear, though a substitute, the rifle, has ostensibly replaced most spears.

Given that kind of observation, I'm not so sure that significant or "magical"-order-of-magnitude leaps in human science and engineering are always going to progress. I think there comes a time when all the ideas have been burnt out until the next great breakthrough in science.

Ergo, like my friends and I used to say when we were kids, "you don't know what they'll be able to do in the future...", or, more precisely, we don't know what other races have left behind as they've advanced and moved on. There may be a few left over ringworlds and/or Dyson spheres here and there.

As for the Imperium building one? I think it's up for debate (which is what we're doing here). Either way I'm going to put something forth in the coming year or two.

Argue on. I think I'm done....again

p.s. I also like the pocket universe thing.

 

[Hyphen]

Some quick notes, when we discussed ringworlds back in 2004 or thereabouts (and before then), I did have plans to create a sourcebook for one, and a few other materials.

Then there is the (probably out of print) original Chaosium Ringworld boxed game, published back in 1984.

A few hardy souls are still working on it.

http://www.dennisantinori.com/RingworldRPG/4555.html

BTW, just a few points to discuss:

a. What of Garyius2003's idea of two movable walls? You slot them into the ring, stretching them across the width of the ring floor, between the two sidewalls. Then dump material (soil, water, air) between them. Of course there's only the minor matters to contend with of how to keep them vertical and how to seal them at the edges - and that you probably have to dump a counter-weight of material on the other side of the ring to keep it stable - but still...

b. I remember reading something from Niven himself about 10 or 15 years ago, when he suggested that carbon-fibre nanotubes may possibly be a reasonable substitute for scrith. Years ago, after the first book, some physics person had worked out the required tensile strength of scrith and sent it to Larry. Apparently, the theoretical strength of nanotubes is pretty close to this tensile strength. Weave them together, spin them like a cowboy's lasso, and voila! you have the canonical semi-stable, circular, spinning ring.

c. "As for the Imperium building one?" There would need to be a damn good reason. In Known Space, where habitable planets appear to be few and far between, and where the Pak live, maybe there's a good reason. In the Imperium, with 11,000 worlds of lebensraum, not so much.

 

[Marchand]

c. "As for the Imperium building one?" There would need to be a damn good reason. In Known Space, where habitable planets appear to be few and far between, and where the Pak live, maybe there's a good reason. In the Imperium, with 11,000 worlds of lebensraum, not so much.

As I recall, in Known Space, the Ringworld was built as a place to ride out the explosion of the galactic core.

Now in Traveller, we have the Empress Wave...

 

[BlackBat242]

to use 1G spin "grav" to maintain an atmosphere that people can breathe is at least 50km sidewalls. To maintain earth-standard atmosphere at same 1G, you're looking at least 100m. Really, you want about 500 km for safety' sake, and you NEED the occasional baffle to keep the air moving. Even with baffles, unless they cross the whole width, you're going to have a steady wind out of spinward at altitude.

So, we're looking at stuff with a specific gravity of about 30+... it's collapsium of some form.

Unless you use grav plates to hold the atmosphere in place - then you don't need the spin, nor do your walls need to be as high.

 

[aramis]

Unless you use grav plates to hold the atmosphere in place - then you don't need the spin, nor do your walls need to be as high.

You need the same height to hold in 1 Atm of pressure at surface whether it's by spin or by gravitics. Forcefields, perhaps, could replace it, but I'd not want to trust them.

 

[Chuck Anumia]

Unless you use grav plates to hold the atmosphere in place - then you don't need the spin, nor do your walls need to be as high.

You need the same height to hold in 1 Atm of pressure at surface whether it's by spin or by gravitics. Forcefields, perhaps, could replace it, but I'd not want to trust them.

I was thinking perhaps a hybrid of spin + Forcefields/grav plates as a secondary or backup plans.