Ring Worlds and Dyson Spheres revisited.

[BlackBat242]

Rice is the most-eaten* food-stuff in Terra, composing over 20% of the total human calorie consumption for the entire planet - and by itself is pretty bland and flavorless.

But look at how many recipes there are that use other foods to flavor and dress up rice - millions perhaps.


* It is actually only #3 in agricultural output, behind maize and sugarcane - but large amounts of both of those are used for non-human-food uses, animal feed and fuel production for corn as major examples.

Both maize and sugarcane are also extensively processed into sugar/corn syrup/etc, with the vast majority of the bulk and food content being discarded or further processed into non-food materials.

 

[nobby-w]

I can't access the source you quote. How many people would New Zealand's exports feed?
[...]
Hans

From the article, about 3% of total global dairy production from a country with something like 0.05% of the global population and .17% of the total global land area, of which about 45% is arable.

Now, NZ is a couple of small islands¹, and quite mountainous, so the actual land area available for dairy production is limited. The demand for NZ dairy products far outstrips the available supply - to the extent that some really unsuitable land is being converted for dairying.

If you had a land area the size of (say) Africa or the continental U.S. where the climate suited some sort of agricultural production like that you could easily export an order of magnitude more, which could genuinely make you a primary agricultural supplier to a world of 3 population sizes larger.

However, in this situation you might well find the population expanding quickly as folks from the larger world see how much money there is to be made in this product. This could drive your population digit up by a factor or so over a couple of generations.

¹Plus some even smaller ones.

 

[McPerth]

Two more things I thought (unrelated to each other):

1) Heat:

A Ringworld will always present the same face to the sun it is orbiting arround. I might be wrong, but I guess that means there's no "night time" too cool out its surface, so, along the years, it would accumulate heat.

I don't believe even if some night is achieved by interposing something (IIRC in Niven's book there were some panels so acting), I'm not sure it will be enough to radiate the head, as it will be against something closer to the sun than yourself, and some radiation will reach anyway.

The cooling in worlds is achieved by rotation (and axial tilt), and in tidelocked worlds by the convection from the cooler face to the hotter one, must be somewhat compensated for a Ringworld to be habitable.

Off course, we can handwave it (after all it's TL25+), but I guess that's not the goal of this thread...

2) Internal communications:

With the Ring meaning those enourmous distances and gravitics limited use (as discused before, due to the small "radius" of the ring section), Iguess most internal communications (aside from radio/beam, I mena for physical objects) must be by thruster powered shuttles, full yas if it was several different planets (while you can reach other Ring sections without them, travel is quite long, to say the least).

This is not really a problem on building them, but it's something I think must be taken into account when doing it, unless you want several different zones without too much communication among them. I'd expect quite a lot of spaceports for internal communications in such an structure...

 

[whulorigan]

1) Heat:

A Ringworld will always present the same face to the sun it is orbiting arround. I might be wrong, but I guess that means there's no "night time" too cool out its surface, so, along the years, it would accumulate heat.

I don't believe even if some night is achieved by interposing something (IIRC in Niven's book there were some panels so acting), I'm not sure it will be enough to radiate the head, as it will be against something closer to the sun than yourself, and some radiation will reach anyway.

The cooling in worlds is achieved by rotation (and axial tilt), and in tidelocked worlds by the convection from the cooler face to the hotter one, must be somewhat compensated for a Ringworld to be habitable.

Off course, we can handwave it (after all it's TL25+), but I guess that's not the goal of this thread...

The ring will have an outward facing side (the uninhabited side) that will always be in shadow. With the right (superconducting) materials, it ought to be possible to bleed the heat from the inner surface "day-side" to the outer surface "space-side". The differential could also be used as a power generation system.

 

[robject]

Two more things I thought (unrelated to each other):

1) Heat:

A Ringworld will always present the same face to the sun it is orbiting arround. I might be wrong, but I guess that means there's no "night time" too cool out its surface, so, along the years, it would accumulate heat.

Thanks for these, by the way. The first made me think of a solution that has an upside:

The ultimate thermocouple.

2) Internal communications:

Teleportation in the low TL 20s. I think the effective range is 27 light minutes or so per leg. That still doesn't place a limit on the ringworld's size, though, since multiple hops at 27 lm a hop can get you about anywhere in a system. Unless there is a heat problem there (I guess you'd need a Heat Sink).

Note that these problems-and-solutions mimic those of psioncs. By coincidence, psionic engineering shows up in the mid TL 20s.


Niven's Ringworld would have a bigger communications problem.

In both cases, the rims may still be full of starports, and Niven's ring would have spaceports in the interior (the ring is a million miles wide...).



Thinking about teleportation. 30 light minutes x 1 light-hour / 60 l-m x 1 light-day / 24 light-hours x 1 light-year / 365 light-days x 1 parsec / 3.26 light-years

= 1 / (48 x 365 x 3.26 )
= 1 / 57,115

It would take 57,000 of those to reach across one parsec. Make them starship-sized and you could get from one place to another in about a day, if they were close and you were going fast. Now that would be some transit system. Try to keep them all in sync too.

That's what's nice about TL 30: pocket universes.

 

[McPerth]

Thinking about teleportation. 30 light minutes x 1 light-hour / 60 l-m x 1 light-day / 24 light-hours x 1 light-year / 365 light-days x 1 parsec / 3.26 light-years

= 1 / (48 x 365 x 3.26 )
= 1 / 57,115

It would take 57,000 of those to reach across one parsec. Make them starship-sized and you could get from one place to another in about a day, if they were close and you were going fast. Now that would be some transit system. Try to keep them all in sync too.

That's what's nice about TL 30: pocket universes.

I may off course be wrong, and maybe I mix up with other games, but I always assumed that Teleport was light-speed (what is practically instantaneous at any practical range). If so, it's use at interstellar scale would be unfeasible...

 

[tjoneslo]

Two more things I thought (unrelated to each other):

1) Heat:

A Ringworld will always present the same face to the sun it is orbiting arround. I might be wrong, but I guess that means there's no "night time" too cool out its surface, so, along the years, it would accumulate heat.

The Ringworld (like planets) will heat up to their Black Body temperature. If you heat a object over this temperature, it will radiate (i.e. cool itself) until it reaches the balance between the incoming solar radiation and the natural tendency to re-radiate the heat into the 3 degree vacuum.

Most habitable planets are somewhat warmer than this because of their atmosphere (which retain more heat) or because of internal heating processes.

As whulorigan points out, you can use the temperature difference between the day-side and night side to generate power.

 

[robject]

I may off course be wrong, and maybe I mix up with other games, but I always assumed that Teleport was light-speed (what is practically instantaneous at any practical range). If so, it's use at interstellar scale would be unfeasible...

I have not understood this to be true. Adventure 12, Secret of the Ancients, certainly mentions portals placed up to 27 light-minutes apart, but not mentioning that it actually takes 27 minutes to teleport from one end to the other.

 

[rancke]

I have not understood this to be true. Adventure 12, Secret of the Ancients, certainly mentions portals placed up to 27 light-minutes apart, but not mentioning that it actually takes 27 minutes to teleport from one end to the other.

There's an adventure in one of the Challenges (I'm not sure which one) that has a circle of habitats in space connected by teleport disks (like a string of pearls). Perhaps there's a mention of that aspect?


Hans

 

[robject]

There's an adventure in one of the Challenges (I'm not sure which one) that has a circle of habitats in space connected by teleport disks (like a string of pearls). Perhaps there's a mention of that aspect?

No idea. I don't have the Challenge mags either.

 

[inexorabletash]

There's an adventure in one of the Challenges (I'm not sure which one) that has a circle of habitats in space connected by teleport disks (like a string of pearls). Perhaps there's a mention of that aspect?

Ch#27. It says "The portals in the pearls transport individuals instantly to the next pearl."

 

[rancke]

Ch#27. It says "The portals in the pearls transport individuals instantly to the next pearl."

Thank you.

That doesn't help much. Taken literally, 'instantly' would mean 'faster than light', but one could argue that it wasn't meant literally. I guess a command decision is required.


Hans

 

[SanDragon]

The Empress was 'seen' before the Wave hit.

Faster than light.

Psionic Transfer drive (unless FF&S is anethema) requires 1 hour preparation and is in transition for one hour.

Sounds like a Referee's call until The Emperor calls it.

 

[robject]

Adventure 3, Twilight's Peak. The teleport pads are instantaneous, but they are very short range (a kilometer?) so no real help there.


I feel like entering an errata for T5.09 on this. I don't like the description being Star-Trek-like. In fact I do not like any description at all. It depends on... the technology. Actually, it depends on Marc. I can lodge a complaint and see what happens.

 

[McPerth]

I began saying that I may well be wrong on that or making a mix-up with other games

Adventure 3, Twilight's Peak. The teleport pads are instantaneous, but they are very short range (a kilometer?) so no real help there.

Most teleports (even máximum range for psionic teleport) are too short ranged to discriminate among instantaneous and lightspeed...

I feel like entering an errata for T5.09 on this. I don't like the description being Star-Trek-like. In fact I do not like any description at all. It depends on... the technology. Actually, it depends on Marc. I can lodge a complaint and see what happens.

Usually psionics have not been seen as depending on thech, but enterily another matter. About depending on Marc, I agree, at least for Traveller...

 

[aramis]

McPerth - note that psionic teleportation under MT is capable of going to "extreme orbit" range. 5e9 m. more than 1.66 LS. Sufficiently far to notice LS lag disconnects.

 

[McPerth]

McPerth - note that psionic teleportation under MT is capable of going to "extreme orbit" range. 5e9 m. more than 1.66 LS. Sufficiently far to notice LS lag disconnects.

Theoretically you're right, as no range limit is set and in MT it costs 1 psi point per range band, though practically distances you can teleport are quite shorter...

As said, I probably mixed up concepts with other games...

 

[Cryton]

IIRC there are several different varieties of teleporter in Science fiction.

Matter-Transport ~ Star Trek like, takes you apart and re-assembles you at the destination. Usually limited by the speed of transmission.

Psionic ~ said to be instantaneous.

Folding space ~ Includes Dune's space folding and the Jaunting psionic special talent from Dragon magazine. Also the basis for the current Warp Drive theory.

Wormhole ~ IIRC is the basis for Traveller Ancient teleport networks and their ability to pinch off pocket universes. Assumed to be instantaneous as well, but not always, as transit time through the wormhole could take time, or not, depending on the length of the wormhole itself.

All may or may not have massive power requirements. May or may not have issues with heat changes at the distant end. All may or may not have issues with vector changes at the distant end. All have been used in various editions of Traveller. All are theoretically possible in the real world as well.

What style of teleporter are you guys planning on using? I imagine that would be the first real question to answer.

 

[tjoneslo]

The Empress was 'seen' before the Wave hit.

Faster than light.

Psionic Transfer drive (unless FF&S is anethema) requires 1 hour preparation and is in transition for one hour.

Sounds like a Referee's call until The Emperor calls it.

Don has confirmed that the Empress Wave, a true psi effect, is in official canon an FTL psionic phenomenon. So we know PSI can go FTL.

In addition to FF&S, there are other mentions in canon of Psionic Transfer drive, so it is very possible for PSI teleport to be FTL. It may be that the un-enhanced version is light speed limited (it's also has some other real physics limitations). But there may be versions that can work FTL.

 

[SanDragon]

Personal teleport may be faster than light.

The 1 hour prep and transition was when the Psi is interfaced with a Psi-drive.