The Nightstar Zoo

Heh, a great little accidental put-down.

Come to think of it, I remember a similar gag used in a fanfic I read some time ago, set just after the turn of the 25th Century. Two tourists visiting Paris come across the Pompidou Centre and look it up in their guidebook.

"Interesting building, when is it expected to be finished?"
"Um... nineteen seventy-seven."
"... Oh."

I've been there, not long after it was finished, and I agree.

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“Despite rumor, Death isn't cruel — merely terribly, terribly good at his job.”
Terry Pratchett, Sourcery

HAH!

I like her way of thinking. But I do see maybe why Petey decided against building a giant can full of sky and instead went for "giant pizza slices floating alone"...

Great idea, put all your citizens in one city wheel when someone is shooting at you. Wait no, not that good.

It wouldn't necessarily need to be ALL of them in one wheel. I think 3 to a wheel would be ideal. Second, they weren't actually shooting at his cities exactly, they were shooting at anything with annie power. If they start shooting at any of his cities now there's little he can do to stop them from shooting all of them. Third, even if all the cities were in one wheel, shooting one of them will only at worst temporarily disrupt the spin in the others.

Shoot out the center hub ...

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I hope Para never plays with Tenzy. The result would be terrifying.
Para and Petey need to have some dialog together. Just because.

Take two rocks.
Tie them to opposite ends of a string.
Spin the string, letting the rocks fly at the ends like some giant bolo.
Fill the rocks with people
Imagine the worst case failure from deliberately breaking bits.

Take a wheel.
Spin the wheel.
Fill it with people.
Imagine the worst case failure from deliberately breaking bits.

Now, between a rock and a wheel, where do you want to find yourself?

A spun up wheel doesn't need a hub.

Do explain those worst cases, please. Either way, assuming the enemy isn't stupid so they actually aimed for a habitat, rather than a "string", you've got a lot of trouble brewing.

Short form, the string with rocks? Think of it like a stick. Damage to any point is just that, damage at that point. It does not move or progress as a property of the stick.

A spinning wheel can be thought of as an arch that is composed entirely of key-stones. Remove one keystone and the nature of the whole thing causes it to collapse, or more properly, break the rim, and the wheel stretches itself out to a string that is 2 pi-r long,applying extra force to the ends, and held together entirely by tension, where compressive forces might have been in the original design... if you don’t plan it very carefully, a large enough spinning wheel will destroy itself once it’s rim is cut.

That's the thing though, with PTUs and engineers who know what they're doing, structural damage to one bit could be contained, and there's precedent for both cans full of sky, and all-stars. Though yes, if the enemy instead aimed for spinning it up...well, I think that the population would be dead from increased G's before the thing would shatter. That's of course...going on my personal speculation on how strong PTUs are, and how capable Kevyn&co. are.

If that string is cut then people will find themselves in free fall while the habitat goes hurtling at... Idunno, whatever the centripetal velocity is.

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Rule of thumb is that if you need to use a squeegee, they're at least Laz-4.

If it's a wheel, and the wheel is cut, it's going to stretch out regardless of how strong the materials are.

Say it's PTUs. If the wheel of PTUs gets cut, then all that tension from rotating is suddenly no longer balanced. The mass near each cut end will want to fly in opposite directions, while, to conversve angular momentum, the side opposite the damage will want to migrate towards the center of rotation. This will cause the wheel to uncurl. Anything towards the inside of the wheel will get stretched, anything towards the outside will get compressed. Since these forces increase with strength with mass, it doesn't matter how strong the wheel is, this will happen (stronger=more mass, especially when using PTUs).

Even if PTUs are amazing enough to not crack in this situation, there will still be catastrophic damage to the structure as things bend and stretch.

Four things.

• One, if the materials ARE strong enough, for their mass, then the structure COULD be 'C' shaped, and still spin. It'd be lopsided, so down would suddenly be more toward the baseboard in much of the structure, but it'd still be mostly toward the outer rim.
• Two, if the enemy is shooting at the wheel, they've been found and might as well turn the gravity back on.
• Three, the teraport has already been established as capable of converting inertia to mass, and vice versa. If the structure is about to fly apart, because it's just been fired upon, port the thing to a new location, but with a quarter the rotational speed. This lets you, reasonably easily, go about repairing the damaged bits while the plumbing, mostly, doesn't get too badly mixed with the air. (Oh, and issue a requirement that EVERYONE sits down..and maybe add some polymerizing agent to the toilet feed water. Splashes in reduced gravity would be rather unpleasant.)
• Four, there is no reason not to build a habitat, out of the available supermaterials, that can survive a 1G spin without a hub, likely even in the event of a break, then go ahead and build that hub anyway. For starters, that 0G hub would be easier to dock in, is still a decent place to put the reactor, and can serve as a backup to the rim should the rim get cut.

The most practical, this time, would be to port all the cities together, with a much larger combined power hub in the middle, and close enough to run a pressurized gangplank, and possible mag-rail, from city to city. The job of figuring out which habitats need to be on which level has already been done, and there does appear to be a good amount of high traffic capacity walkway on the outside. Further, since the cities are already conically shaped, they'd "nest" pretty well together, and the real challenge would be deciding how closely to space them such that people with windows still enjoy views that aren't ones of their new neighbors interiors. Maybe half a kilometer between cities? Maybe only two hundred meters? Better polarize the glass.

Ah, finally a relationship for a Kevyn not based on abuse.

Jengisha is smooth like butter. She can keep Kevyn Prime grounded.

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The difference between theory and practice is that theories seldom involve people screaming in terror.

Forum weapon: the humble Northern Pikestaff

• Materials: you often have to make do with the materials you have, not the materials you want. Even then, you are limited by your design and restricted by your needs. The image I like to use for this is: picture a mobile weapons platform fast as a fighter jet (Mach 2+), with the agility of a helicopter (VTOL/hover/reverse and side movement), the armor of a tank (35+cm of reactive/composite/etc), the firepower of a battle ship (9 16 inch cannons, 12 5 inch cannons, 40+ long range missiles, etc, etc, etc), and small enough to park in a 2-car garage. Except we don’t have the materials to make that happen, never mind the technologies. Sure, you can declare ‘well,use PTUs’, except PTUs are the resource of scarcity and nobody’s demonstrated possession of a working PTU printing press. Using them to house every living being of an empire won’t pass inspection as viable.
• turning the gravity back on doesn’t necessarily work, if you’ve been shot at things are going to be failing. Better to have a design that ‘fails safe’ and not ‘fails by creating new problems.’ High density power sources, like those used to power/manipulate gravity have also had an annoying tendency to get shot at in this conflict (read: tend to be made into the component that fails) by parties on both sides of this conflict. Your hub reactor would get shot out, potentially taking out the structural support of the hub itself, and then turning on rim reactors to assert a different gravity source may simply turn them into fresh targets.
• if the structure’s just been fired upon, you’re under attack. Standard attack doctrine is to deploy your own TAD, denying teraport capability to the opponent. Depending on using teraports during a defensive action seems foolhardy. The attacker has demonstrated spotter capability, it’s not hard to imagine them giving their spotters TADs.
• lets be honest, you are at war. On a war footing, do you consolidate your assets into a single juicy (and indefensible) target, or do you distribute them?

I think I see where the comic is going with this.
I don’t know if I’ll agree with it, but I’ll grant that artistic license exists to let artistic things happen, and I don’t doubt that there will be art involved in the destination of this particular sub-arc. I’ll hush now and watch things unfold, there may even be a good answers presented for my concerns, but I’d honestly prefer to see them from the author first. He’s shown a high level of attention to detail time after time, I doubt my concerns were flat out ignored in his solution.

Now if only he's stop acting so pissy just because someone pointed out a flaw in his designs. Even if that someone is supposed to be a "mere" grunt.

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The MacNut
Artist and writer of The Vanguard, a space opera superhero comic.

Everyone acts pissy when someone points out a flaw in their design in this situation. It's like being told, "you thought you were done, but you actually have a lot more work to do." Even the most humble person would still be insistent about being told exactly what is wrong.

I just realized, if that bit of string snapped it's not going to be a simple freefall. The Centripetal velocity at the base of the city is going to be much much higher than the top, so if the string snaps the city is going to fly off while tumbling at a very fast spin. Gravity will be inverted for the upper levels, cross forces may rip the city apart, and people probably won't survive the initial changes in velocity.

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Rule of thumb is that if you need to use a squeegee, they're at least Laz-4.

The question of how the city would endure a direct assault is irrelevant; no baryonic civilization will be able to assault it except with Long Guns, and destroying the cities with Long Gun fire will antagonize Petey but not militarially weaken him. Anyone with Long Guns intent on pure bloodshed would simply continue firing until the city was slag.

The city needs to avoid mechanical failure tearing it apart and be suitable living space. Those are the only design considerations.

We actually have no proof that the Ofans are any better at making PTU, they may have salvaged it off of older, now dead cultures.

That's what the star forge was, the proof. Where they got that technology from initially isn't really as important as the fact that they had it and used it to crate worlds of the stuff.