Northstar Ringworld

Discuss the Traveller RPG and its many settings
Tom Kalbfus
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Re: Northstar Ringworld

Postby Tom Kalbfus » Mon Jan 16, 2017 2:18 pm

Yatima wrote:Let me have one last go at contributing to this thread in the spirit of imaginative interpretation of UPPs and Descriptions.

A ring of habitats can be something quite distinct from an Asteroid belt, if you want it to be. In his book The Millennial Project: Colonizing the Galaxy in Eight Easy Steps (https://en.wikipedia.org/wiki/The_Mille ... Easy_Steps) Marshall Savage spits that the first step in harnessing more of the power of the energy output of a star (the very purpose of a Dyson sphere and its derivative, the Niven Ring World) is to create thousands, then millions of individual habitats (using asteroids, artificial habitats etc). In this model, the Dyson sphere is not so much a solid shell around the star, but rather a Dyson cloud of artificial and individual habitats.

I find this a fascinating concept, and one you could see emerging much more naturally than the monolithic engineering project that a Ringworld or Dyson sphere requires.

So you could choose to interpret this description and UPP in this way, and therefore make it a lot more interesting than a mere Asteroid Belt.

J
I don't believe Marshall Savage called it a "Ringworld" however, his sort of habitats did not rotate by the way, he was looking for a way to adapt humans to living in zero gravity, using electroshock therapy to stimulate the muscles. I see the term "Ringworld" and only one image comes to mind.
Image
Ringworld has its smaller cousins, there is the Banks Orbital and the Halo, but if your going to have one ringworld, I would choose the big one. Northstar is the perfect sun for one, it is a class G2 V Solo star just like out Sun, and it only has 4 asteroid belts with no planets to disturb the ringworld. An O'Neill colony is sort of ho hum, the population of Northstar is only in the hundreds of millions. The entry mentions the presence of a ringworld as if that was a minor thing. I would think if there was a ringworld there it would be sort of a big deal! Obviously we need an explanation to square this circle.
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Re: Northstar Ringworld

Postby Yatima » Mon Jan 16, 2017 5:11 pm

I don't believe Marshall Savage called it a "Ringworld" however...
I absolutely agree, he didn't use that term - Dyson cloud is the term he used IIRC. It's not my intent to get sucked into a debate on what the description and UPP mean in a canonical sense or otherwise, I'm simply trying to suggest creative alternative ways to interpret these sorts of things, such that you can have an interesting environment that isn't necessarily a Nivenesque Ringworld.

Not sure if I'm being helpful - I'll stop if not.

J
"I hunker in the corner facing the door. Anyone that opens the door gets a full clip."
Tom Kalbfus
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Re: Northstar Ringworld

Postby Tom Kalbfus » Mon Jan 16, 2017 6:49 pm

Yatima wrote:
I don't believe Marshall Savage called it a "Ringworld" however...
I absolutely agree, he didn't use that term - Dyson cloud is the term he used IIRC. It's not my intent to get sucked into a debate on what the description and UPP mean in a canonical sense or otherwise, I'm simply trying to suggest creative alternative ways to interpret these sorts of things, such that you can have an interesting environment that isn't necessarily a Nivenesque Ringworld.

Not sure if I'm being helpful - I'll stop if not.

J
There are various degrees of Nivenesque, the G2 V star of Northstar is a more close match to our Sun than Niven's for example. So for the same of argument, I'll assume the Northstar sun has the same brilliance and mass as out own Sun and that it has four planetoid belts and no planets whatsoever. The belts are the leftover material after the construction of the ringworld. It is puzzling if the ringworld is not the mainworld after all! Now how do we square this circle? What if the ringworld exists in a parallel universe, the stars are in the same position as in the OTU, but in this parallel universe, the Jump Drive was never discovered. There is however a stargate in the OTU mainworld asteroid belt of Northstar which leads to the parallel universe Northstar system where this ringworld exists. Who built the stargate? Why the ringworld builders of course, you see there was not enough material in their own system to build the ringworld, so they had to mine the materials in a parallel universe to obtain the material they needed. The never developed the Jump Drive, and the wormholes they created split the universe in two for each one, one universe has a ringworld in this system, the OTU Northstar system does not! The ringworld is one million years old. Lets just say each star in the ringworld universe has its parallel in the OTU, but they are not exactly in the same positions. It could be that the ringworld is at the future end of this wormhole/stargate. There is a completely different history in the ringworld universe, but the short version is that the Jump Drive was never developed, and human colonization proceeded with slower than light spaceships. Who built the ringworld? Since this one seems designed for humans and Earthlife, there is one obvious answer. The ringworld seems to run on automatic, the humans living on it don't seem to have much control over it, there is no single world government either, civilizations exist are various tech levels on the surface, the most advanced ones live near the walls, where there are exploitable minerals for industry in the spill mountains.
Tom Kalbfus
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Re: Northstar Ringworld

Postby Tom Kalbfus » Tue Jan 17, 2017 3:59 pm

Yatima wrote:
I don't believe Marshall Savage called it a "Ringworld" however...
I absolutely agree, he didn't use that term - Dyson cloud is the term he used IIRC. It's not my intent to get sucked into a debate on what the description and UPP mean in a canonical sense or otherwise, I'm simply trying to suggest creative alternative ways to interpret these sorts of things, such that you can have an interesting environment that isn't necessarily a Nivenesque Ringworld.

Not sure if I'm being helpful - I'll stop if not.

J
Actually in my mind there are three types of ringworlds type 0, type 1, and type 2, each number corresponds to the level of civilization required to build it. Let me go over the different types of ringworlds.

Type 0 ringworld: Stanford Torus
Image
The Stanford Torus is an example of a Type 0 ringworld, it is a type of space settlement that is built by a society that does not have control over all of its worlds resources.

Type 0 Ringworld: Elysium Space Station
Image
The Elysium movie space station is a larger version of the Stanford Torus it is bigger and more expensive to build than the first.

Type 0 Ringworld: Bishop Ring
Image
This is the largest of the type 0 ringworlds it is 2000 kilometers in diameter, thus it is smaller than most worlds. This one is the smallest ringworld that relys on centrifugal force to hold in its atmosphere, it shares that in common with Niven's ringworld.


Type 1 ringworld: Halo
Image
The Halo is a type 1 ringworld, it is a ringworld the size of a planet, there are two types, one has a planet in the center the other kind has nothing in the center.

Type 2 ringworld: Banks Orbital
Image
The Banks orbital is even larger still, it is so large that it takes 24 hours to do a complete rotation while that rotation at the same time provides 1-g of centrifugal force on its surface. Unlike the Niven Ringworld, on this one, the Sun both rises and sets and there are seasons if the Banks Orbital is inclined to its orbit.

Type 2 ringworld: Niven Ringworld
Image
This is the largest of the ringworlds, the Niven ringworld has a star at its center, the ringworld inhabits the habitable zone of that star. The Sun stays at the Zenith position of the ringworld's sky and relies on an inner ring of shadow squares to provide night with periodic eclipses of the sun to provide shade.
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Re: Northstar Ringworld

Postby heron61 » Tue Jan 17, 2017 10:00 pm

Tom Kalbfus wrote:Actually in my mind there are three types of ringworlds type 0, type 1, and type 2, each number corresponds to the level of civilization required to build it. Let me go over the different types of ringworlds.

Type 0 ringworld: Stanford Torus

The Stanford Torus is an example of a Type 0 ringworld, it is a type of space settlement that is built by a society that does not have control over all of its worlds resources.

Type 0 Ringworld: Elysium Space Station

The Elysium movie space station is a larger version of the Stanford Torus it is bigger and more expensive to build than the first.

Type 0 Ringworld: Bishop Ring

This is the largest of the type 0 ringworlds it is 2000 kilometers in diameter, thus it is smaller than most worlds. This one is the smallest ringworld that relys on centrifugal force to hold in its atmosphere, it shares that in common with Niven's ringworld.

Type 1 ringworld: Halo

The Halo is a type 1 ringworld, it is a ringworld the size of a planet, there are two types, one has a planet in the center the other kind has nothing in the center.

Type 2 ringworld: Banks Orbital

The Banks orbital is even larger still, it is so large that it takes 24 hours to do a complete rotation while that rotation at the same time provides 1-g of centrifugal force on its surface. Unlike the Niven Ringworld, on this one, the Sun both rises and sets and there are seasons if the Banks Orbital is inclined to its orbit.

Type 2 ringworld: Niven Ringworld

This is the largest of the ringworlds, the Niven ringworld has a star at its center, the ringworld inhabits the habitable zone of that star. The Sun stays at the Zenith position of the ringworld's sky and relies on an inner ring of shadow squares to provide night with periodic eclipses of the sun to provide shade.
That's an excellent classification system, although I would change it in one way. I'd definitely put a Banks Orbital into the category of Type 1 ringworlds, since depending upon the width of the Banks Orbital (and assuming they are both equally thick), a Banks Orbital is between 0.01% and 0.1% (between one ten thousandth and one thousandth) the mass of a ringworld, which seems like it a size category down from the insane immensity of a Niven ringworld.
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Re: Northstar Ringworld

Postby Tom Kalbfus » Wed Jan 18, 2017 3:59 am

I'll use this site to determine the size of a Banks Orbital. Lets assume this orbital has a gravity of 1-g and a day that is 24 hours long.
http://www.artificial-gravity.com/sw/Sp ... inCalc.htm
The Banks Orbital has a 24 hour rotation period, which means it rotates 360 degrees every 24 hours, which means it has an angular velocity of 0.00416666666666666666666666666667 degrees/sec.

These are the results spin calc gave me.
Radius (R) 1,854,336 kilometers
Angular Velocity (W) 0.0041666666666666666667 degrees/sec
Tangential Velocity (V) 134,851 meters/sec
Centripetal Acceleration (A) 1-g

Now as to its width, lets make it 20,000 kilometers.
This Banks Orbital has an axial tilt of 23.4392811°, same as the Earth.

Lets say it appears in the Northstar system in a circular orbit with a radius of 149,598,023 km, and an orbital period of 365.256363004 days.
This ringworld arrives out of jumpspace, it originated from somewhere unknown, spent about 5 days in darkness and suddenly arrives in the Northstar system. The climate is tropical the Sun from the surface appears to rise in the East and set in the West. There is no variation of climate due to latitude as there isn't any, just lots and lots of jungle. There are oceans and mountain ranges, every type of terrain, at higher elevations you have some permanent snow, the snow caps melts a little when the Sun is directly overhead, and then expands a bit when the Sun is more angled. Walls holding in atmosphere are 300 kilometers high. The Banks orbital is in orbit, so it is fairly stable, and there are only 4 asteroid belts in this system and not much else. Surface area of the Earth is 510,072,000 km^2, the surface area of this Banks orbital is 233,022,734,195 km^2, which means it has a total surface area of 456.8428 Earths, this is not so overwhelming for the OTU. Still its a lot of living space. About 4.5 Saturns worth of surface area. The meteor defense system reacts to objects above a certain mass moving inwards on a collision trajectory at too high a velocity relative to the spinning surface of the orbital, that means a relative velocity greater that 10 km/sec, if your ship gets below that or has a hull displacement of less that 1000 tons, then it gets ignored as not a threat.
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Re: Northstar Ringworld

Postby Tom Kalbfus » Mon Jan 23, 2017 4:10 pm

I'm thinking of putting a Banks Orbital in orbit 2 (The equivalent orbit of Venus for this system.) Maybe give the orbital a 0 degree inclination to its orbit so a part of it is always eclipsing the Sun to the other part The chart below is a size comparison of what the Sun appears in the sky of this Banks orbital at high noon compared to the size of the Sun as seen from Earth.
Image The four asteroid belts begin at orbit 3 beyond this. To create seasons, the Orbital uses active refrigeration powered by solar collectors on the bottom (outside) of this ringworld.
This Orbital is 12,900 kilometers wide, this allows the Sun to give off slightly more light at the high noon position in the sky to compensate for the less light it gives off due to the Orbital appearing wider closer to the horizon. the mass of this entire construct is about that of the planet Venus.
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Re: Northstar Ringworld

Postby Yatima » Mon Jan 23, 2017 5:19 pm

@Tom - do you have a copy of the Chaosium Ringworld RPG? I see that there's one up on Waynes Books right now,

http://www.waynesbooks.net/?page=shop/f ... set=0&fs=1

I have this game and the Ringworld Companion and it's an absolute goldmine of information on Niven's Ringworld. It was used by Niven and the team of authors on the Man/Kzin wars as the shared-world bible and the material in it is useful for anyone creating this sort of setting, even on a Banks Orbital of the size you propose.

Just mentioned it in case you (or anyone else reading this) fancies picking up this amazing little game.

J
"I hunker in the corner facing the door. Anyone that opens the door gets a full clip."
Tom Kalbfus
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Re: Northstar Ringworld

Postby Tom Kalbfus » Mon Jan 23, 2017 7:25 pm

Yatima wrote:@Tom - do you have a copy of the Chaosium Ringworld RPG? I see that there's one up on Waynes Books right now,

http://www.waynesbooks.net/?page=shop/f ... set=0&fs=1

I have this game and the Ringworld Companion and it's an absolute goldmine of information on Niven's Ringworld. It was used by Niven and the team of authors on the Man/Kzin wars as the shared-world bible and the material in it is useful for anyone creating this sort of setting, even on a Banks Orbital of the size you propose.

Just mentioned it in case you (or anyone else reading this) fancies picking up this amazing little game.

J
No I don't, I know that a Ringworld RPG existed, and I also know that Ringworld existed within a setting called "Known Space" which included a bunch of different worlds written about by Larry Niven. Putting a ringworld in the OTU would not be that different from this. A Banks Orbital is of more modest dimensions but still Huge! This one would have the surface area of about 200 worlds, though I haven't done the calculations yet. It probably has the population of an entire sector all in this one world, it has the mass of Venus, and it has a Jump Drive, it is stocked with Terran Derived Flora and Fauna, has a 24-hour day/period of rotation, and a centripetal acceleration equal to 1-g on its surface. It appears in the Northstar system in a circular orbit. The inhabitants talk of there being an identical sun which this World previously orbited and then there was five days of darkness prior to arriving in this system. Presumably that was when this Orbital was in jump space.
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Re: Northstar Ringworld

Postby Tom Kalbfus » Tue Mar 14, 2017 4:16 am

Image
Here is a further refinement on my ringworld/Dyson Ring concept. The above is a Fuller projection of the continents of the Earth spread lengthwise along the ringworld. The scale of these continents is 100:1 of the actual Earth features, the actual detail is considerably different. mountain ranges have many more mountains in them. A river that is 1 mile wide becomes a river that is 100 miles wide, and it has lots of tributaries feeding into it. The climate is determined by active refrigeration of the floor area, the ground absorbs heat from the air, making the climate colder in places that is would otherwise be given the perpetual noon sun.

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