Niven Ring

[Tom Kalbfus]

The picture doesn't show the walls where the thruster towers would be.

Like the people of the original Ringworld, our inhabitants would obviously see the ring as it curves up and fades in the distance. Are the various beings aware they live in an artificial structure or accept this is how the universe is?

It varies much as it does in the OTU, each hex has its own society or not, some hexes are devoid of permanent residents, the population of each hex ranged from uninhabited 0 to tens of billions of people A, tech levels range from stone age 0 to tech level 16(G) the higher tech levels realize what they are living on, particularly those who live close to the rim walls. I am thinking of having the portals large enough to allow the passage through of up to 800 ton starships, all the standard designs, Since these standard designs rely or reactionless thrusters, the convert to magnetic thrusters instead, which means they need to remain with 100 meters of the scrith floor in order to push and levitate off of it. You see the diagram of the ringworld floor? Above the ringworld floor foundation in most places is 20 meters of bonded bedrock plus another 20 meters of loose rock and top soil, so the maximum height of operating maglev vehicles is actually 140 meters, the 100 meter height takes into account the 20 meters of bedrock and 20 meters of top soil, but it doesn't take into account bodies of water. Oceans bottom out at 50 meters on top of the soil and bedrock, so maglev vehicles can levitate 50 meters above the wavetops. the scrith floor underneath the rock and soil mostly determines the topography, the main exception to this would be the spill mountain ranges along the north and south rimwalls, there you have many kilometers of rock and soil and maglev vehicles can't float above those. Starships and smallcraft use their nap of Earth speeds for traveling across the ringworld unless they have reaction motors, otherwise they can't reach space, unless they are somehow lifted to the top of the rim walls and shoved over the edge. there are real starships along the edge of the rimwalls, these tend to be Bussard fusion ramjets, somehow they fuse interstellar protons to provide 1 g of thrust, they can reach most nearby interstellar destinations within a human lifetime and can achieve relativistic velocities as well.

There are also altitude thrusters built into the rimwalls of the ringworld, they world to keep the ringworld centered on the primary star. the thrust they apply to do this juob is minimal precise, those living near the rimwalls can often see a glow in the sky at night when those thrusters are firing, the effect is similar to the Aurora Borealis seen in the polar regions, a blue glow of thruster ions sometimes illuminate the night sky. Often times simply deflecting the solar wind with varying magnetic fields does this trick.

According to my T20 book, the following standard starships have the following Nap of Earth speeds:
Scout/Courier: 1100 kph
Seeker: 1100 kph
Far Trader: 1100 kph
Free Trader: 1100 kph
Safari Ship: 1100 kph
System Defense Boat: 5900 kph
Yacht: 1100 kph
Corsair: 300 kph
Laboratory Ship (the kind in the T20, not the ringship): 300 kph
Patrol Cruiser: 300 kph
Subsidized Merchant: 300 kph
Subsidized Liner: 1100 kph
Mercenary Cruiser: 300 kph
Maximum altitude of 100 meters is measured from the lowest extremity of each starship.
Smallcraft have the following NOE speeds:
Launch: 375 kph
Ship's Boat: 375 kph
Slow Boat: 375 kph
Pinnace: 375 kph
Slow Pinnace: 375 kph
Modular Cutter: 375 kph
Shuttle: 375 kph
Fighter: 375 kph
of course the Mongoose books might have different values for NoE speeds.

 

[Tom Kalbfus]

A little math. I'm going to find out what the rotation rate would be of this Niven Ring.
a = V^2/r
We set a to 9.81 meters per second squared
r = 202,014,501,150 m
and we solve for V
V = (a*r)^0.5 = 1,407,750.779 m/sec or 1,407.75 km/sec
also 0.47% of the speed of light (Fast enough for the interstellar ramjet starships to get started.)
circumference is 2*pi*r = 1,269,294,545.46 km
divide by velocity = 901,647.7 seconds
10.4357 days, or 10 days, 10 hours, 27.46 minutes.

Where shall we place the shadow squares?
What if we placed them at 200,000,000 km from the center of the star? that would place them 2,014,501.15 km away from the ring world.
We could have 365 shadow squares for 365 12-hour long nights with 12-hour long spaces between them. So how big would the shadow squares have to be?
Circumference = 2*pi*200,000,000 km = 1,256,637,061.44 km
divide by 2*365 = 1,721,420.63 km is the length of each shadow square, its width would be 2,000,000 km just to be sure and shadow a section of ringworld from rim wall to rim wall. the shadow squares are held in place by wires of the same strength as the underlying ringworld floor structural material Each of the shadow squares are also solar collectors of course. Perhaps some virtual worlds exist in those as well. The ones in the ringworld floor are powered by temperature differences between the side of the ringworld facing the Sun and the side facing away, part of this is responsible for the "polar" ice caps in the center of each 16,000 km hex. Radators project from the underside directly underneath each polar area, this flow of heat can be converted to electricity and used to power the computer circuits within the ringworld structure itself. Photovoltaic effects power the circuits within the shadow squares.

 

[Tom Kalbfus]

I think I'll change the Hex size to 20,000 km.
Why?
Because the original definition of the meter was 1/10,000,000th of the distance from Earth's equator to the North Pole, turns out the original estimate of this distance wasn't 100% exact, but its close enough for government work as they say. If I make each hex 20,000 km across, the the distance from the center to the edge would be about the same as the distance from the Earth's Pole to the Equator as you follow the curvature of the Earth. This will be great for migrating species on the ringworld, adjacent hexes will have opposite seasons.

I think for a Map of Earth the Dymaxion Projection map works best for the Surface of a ringworld.

The map should be two adjacent 20,000 km hexes, the center of one on the north pole, the center of the other on Antarctica.
I have a map of this projection with 1,000 km hexes if anyone is interested in my sending an attachment by e-mail.
I have to think of a scenario for this map. There could be more than one Map of Earth on the ringworld by the way. A portal opens up in the Bermuda triangle in a matrix simulation of today's Earth. The portal is a hexagon shaped structure 100 meters across, sitting vertically in the Ocean, half underwater and half above, resting on the sea floor on both sides, which is 50 meters deep by the way. A cruise ship passes through, and the ringworld is discovered. Colonists pour through, they find that the mineral wealth of the land masses leave something to be desired, as there is only 20 meters of top soil and loose rock on top of 20 meters of bonded bedrock on top of ringworld floor material, which cannot be mined or worked. The oceans never get deeper than 50 meters, so the obvious resources us fish, as shallow waters in conducive to a lot of fish, practically an infinite supply since this continental shelf does not end, there are no deep oceans on this ringworld, though 50 meter deep oceans are sufficient for most ocean going vessels. Astronomers not the arch in the sky and the shadow squares are quickly discovered. The northern rim wall is 60,000 km to the north.