We now have 3 ringworlds in SCI-FI

[Rigel Stardin]

We now have three types of ringworlds in the Sci-Fi genre. Larry Niven’s classic, Halo’s vision and now Elysium version which I will dub the Ferris wheel. In Niven’s version it took an entire solar system worth of material to create a ringworld. Halo’s version, possibility a large planetary body was used to make it. In Elysium, without real scale, we’ll have to say a small moon or several dozen large asteroids.

If you were to import one of these three into YTU which one would it be and why?

I like Halo’s and Elysium versions. They could be built by a race without devoting their entire system to constructing it. It is also possible that a rich noble or planet wishing to impress their industrial might could conceivably build one without going bankrupted in the process. They could be built by a race whose planet suffered some sort of disaster as well.

From an exploration stand point, they wouldn’t be as large as the classic ringworld and player could spend months rather than years finding out its secrets.

 

[Blue Ghost]

Four ... sort of.

https://www.youtube.com/watch?v=snhU3qlq4N8

 

[mike wightman]

Cough, Culture orbitals, cough...

 

[tjoneslo]

The small end of the "Ringworld" are the Stanford Torus. Or more properly, a ringworld is a scaled up version of the torus.

There is a minimum size you can build these before the spinning causes problems in the residents. But I think the upper end of the Traveller starship construction system, using a dispersed configuration, can encompass the small end of the torus designs.

 

[JimMarn]

Four ... sort of.

https://www.youtube.com/watch?v=snhU3qlq4N8

Ah yes, The Dirty Pair. Scary women with guns.

 

[JimMarn]

The larger it is, the more maps that have to be made.

Another way would be generic maps for different types of terrain, then just make verbal adjustments to what the characters find.

 

[aramis]

The small end of the "Ringworld" are the Stanford Torus. Or more properly, a ringworld is a scaled up version of the torus.

There is a minimum size you can build these before the spinning causes problems in the residents. But I think the upper end of the Traveller starship construction system, using a dispersed configuration, can encompass the small end of the torus designs.

According to SpinCalc, 224m radius is doable for 1G. Given a 7.5m wide ring, 3.1m deck height, that gives such a ring about 32496.4 kL or about 2321 Td. Adding a 3m diameter crossbar adds another 3122 kL, or 223 Td.

Easily within book 2 range, but outside MGT core range.

it's 2 RPM that's the "comfort level".

 

[Magnus von Thornwood]

Elysium.

Elysium is not a Ring World, it is an Orbital Station.

If it does not orbit a star, it is not a Ring World. It is a space station, a torus to be exact.

As to the secrets, about the only secret worth knowing is are there people there and can we sell them overpriced digital watches? Seriously, if it wasn't created by some inscrutable aliens of a bygone age using ultra or magi-tech a Ring World is still just a World, which are usually have unseen lurking dangers. Running around looking for them seems sort of crazy to me. I mean you get hurt and die, but hey it takes all kinds. Call if you find some natives who think digital watches are neato or say bad things happen and you need evac, I'll be here in the ship, with doors locked. :devil:

 

[Rigel Stardin]

The reason I call the Elysium Space Station a ring world is because, Vehicles could land on the station by going over 'lip' of the ring and landing on the interior surface. A Standford Tortus is depicted as being a tube where the habatat ring is located, entry is gained by using of the central core. Space 2001's space station is such a design.

The director made Elysium into a ringworld either for the cool factor, plot device (how else were they going to land ships in the Elysium without encounter athourity...) or had no idea what he was doing. But what made it into a ringworld for me was the narrow landscape and a open top with to high walls to keep the atmosphere in (either through spin or force field). I really don't think we have the technology to even begin to building such an orbital facility, now or in the near future. That's why I dubbed it the ferrris wheel.

Halo's version uses a planet as the central gravity point. Niven's a sun. In Elysium they built the central core into the center of the ring. This provide this style of ringworld with an artifical gravity point and I think great control, making the design more stable. Because now you have center of gravity you can control.

 

[inexorabletash]

You may find http://en.wikipedia.org/wiki/Space_stations_and_habitats_in_fiction#Toroidal_or_annular_habitats useful.

And c/o Orions Arm, the spectrum of rotating ring-like habitats that provide 1G surface:

Stanford Torus: http://www.orionsarm.com/eg-article/48b5f8c61e31e (pros: 20th Century tech; cons: roof, non-trivial lighting)

Bishop Ring: http://www.orionsarm.com/eg-article/460db7f55a8d3 (pros: 21st Century tech; cons: non-trivial lighting)

Banks Orbital: http://www.orionsarm.com/eg-article/4845ef5c4ca7c (pros: natural lighting; cons: unobtanium)

Niven Ringworld: http://www.orionsarm.com/xcms.php?r=oaeg-view-article&egart_uid=5151b9b79834e (cons: unobtainium, unstable, non-trivial lighting)

(For reference, the Halo installations would be somewhere between Bishop Rings and Banks Orbitals, in terms of size and required handwavium.)

The reason I call the Elysium Space Station a ring world is because, Vehicles could land on the station by going over 'lip' of the ring and landing on the interior surface.

That's a nice distinction. A violation of the laws of physics, but it's pretty!

Halo's version uses a planet as the central gravity point.

Wat? The Halo installation orbited at the L-1 Lagrange point between the gas giant Threshold and its moon Basis.

This provide this style of ringworld with an artifical gravity point and I think great control, making the design more stable. Because now you have center of gravity you can control.

FWIW, in the Culture setting, Orbitals have a hub where the Mind(s) typically hang out, but thats just to be equidistant from all points on the ring. There's nothing particularly special about it from a physics perspective.

 

[Carlobrand]

What is "non-trivial lighting"?

 

[Rigel Stardin]

Sorry about the Halo description, I saw an artist drawing of a ringworld circling a planet and thought it was Halo, so now we have four.

 

[inexorabletash]

A Banks Orbital is sized so that it rotates every 24 hours producing 1G. In orbit of a star it gets natural day/night lighting cycles with no need for artificial lighting, mirrors or shadow squares.

 

[aramis]

A Banks Orbital is sized so that it rotates every 24 hours producing 1G. In orbit of a star it gets natural day/night lighting cycles with no need for artificial lighting, mirrors or shadow squares.

SpinCalc gives a radius of 1854335974.6 m ... 1.85 million km radius. About 5.5x the orbital radius of the moon. A banks orbital is thus into the improbably large category - much like Halo, only more-so. (A single deck 7.5m wide would be 135444462395.9 kl, or 9,674,604,456.9 Td... yes, 9.6 thousand million Traveller Displacement tons.... for 1 deck at 7.5m wide (5 deck squares). And, to be blunt, that's about 1% of the minimum width to make it worthwhile, and 1/5th the minimum height to feel "open." (15m, or about 49', is pretty much the minimum for an "open air" feel for the people I know. That's a good height for a gymnasium, pool, or auditorium ceiling.) So, start a banks orbital at about 67,722,231,197,950 kl, or 4,837,302,228,425 Td, or almost 5 million million Td, for a ribbon-like under-1-km wide.

The moon is 98858233792.7 cubic km or 7 million million million Td (US quintilion), so a Banks is in the "raw materials are available in sufficient amounts to do this." I'm not certain if the tensile strength is high enough to keep it together. (which is the largest issue with Niven's Ringworld. The mass is the second largest issue - it's big enough to require multiple systems worth.)

 

[Carlobrand]

...(which is the largest issue with Niven's Ringworld. The mass is the second largest issue - it's big enough to require multiple systems worth.)

Is kinda like tearing down Los Angeles and Miami so you can grow New York City, no? A person's gotta really like having all his eggs in one basket if he's going that route.

 

[BlackBat242]

Or the systems all have little or no habitable territory, and you are making something that can hold a huge population.

 

[aramis]

Is kinda like tearing down Los Angeles and Miami so you can grow New York City, no? A person's gotta really like having all his eggs in one basket if he's going that route.

No. It's like tearing down Jupiter to build Earth II at Earth's L5 point.

 

[BlackBat242]

What is "non-trivial lighting"?

He means that providing lighting for the inhabited surface is a "non-trivial task" - something that requires significant engineering & construction to do.