Big Structures • s******j@**.com 05/08/1996 00:00:000 UTC I doubt anyone will build things as big as a Death Star. Unless it's a giant inflatable designed to scare the bejeezus out of niave young civilizations. I'm curious how big the pieces of a Dyson Sphere (not the bonehead 'Trek / Niven type, with a solid sphere, but the original conception based on Stapledon's _Star Maker_) would or could or should be. I see three types of structure: Solar collectors, which turn sunlight into (antimatter? microwaves for beaming to other structures?) and radiate waste heat. Industrial centers, which either recieve power directly from the sun (for smelting metals or whatnot) or get stored/beamed power and use it to process materials and make things. Probably go whre the materials are, and may be better off far out, where it's cold and there are ice asteroids to pump waste heat into. Habitats. O'Neil - type "space colonies" for living critters. May get direct sunlight or make their own. May not be needed if you've got a civilization of AIs. Fnord --Stefan This post (k) parve. No animals were harmed or killed while making this post, except some skin mites that were unlucky enough to be on my fingertips when I started typing. And a ibex that was really asking for it anyway. Chief Grip: Clarence "Boss" Mulney Assistant Grip: Martin "Hey You" Carnhower -- +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+ ***@***.com ~ s*****s@a*****.***u.edu ~ s******j@**.com http://www.ini.cmu.edu/~sjones/ • p*******x@p***.****i.com 06/08/1996 00:00:000 UTC Stefan E. Jones (s******j@**.com) somehow managed to write: : Habitats. O'Neil - type "space colonies" for living critters. May get : direct sunlight or make their own. May not be needed if you've got a : civilization of AIs. oh? woudl not AIs need power to run? -- 73 de Dave Weingart KB2CWF "Can you find the Valium? mailto:p*******x@****.com Can you bring it soon? mailto:p*******x@e******.*********n.edu Lost Johnny's out there http://www.liii.com/~phydeaux Baying at the Moon" -- Hawkwind • s******j@**.com 08/08/1996 00:00:000 UTC In article <4uc4d0$***@n*******.****.***l.com>, JohnGorno wrote: > The big boys wouldn't have to fake it! They might build a real Big >Structure simply to show they could do it. Possibly. Building a solid sphere for economic reasons is silly, so it would have to be for some Other Purpose. Heck. In one unfinished novel I've got a race that sets off supernova to make nebula floresce pretty. > Now I find myself defending Freeman Dyson from you! I don't recall >poor Larry Niven having anything to do with Trek (tm), but Dyson (and not >Olaf Staplegun, neither!) envisioned his sphere as the logical end result >of a space-living society which collected ever more of its sun's light. No, Dyson got the idea from Stapledon. The critters in _Star Maker_ surrounded their stars with habitats because they were getting desperate. I think he mentions this in _Disturbing the Universe_. URL to check out: http://www.student.nada.kth.se/~nv91-asa/Trans/dyson >He thought they might then de-orbit and connect all the solar collecting >space-habs, whatever, into one solid sphere, Really? I thought the solid sphere was Niven's ignorant interpretation. Where did F.D. write about the solid variety? >another thing that pisses me off about Wimp Trek: Blunderer: in the >opening credits, we have all these neat space settings, but never in the >damn episodes! Yeah. But people don't really watch 'Trek because they actually want to see something about strange new worlds. They want soap opera, EZ-2-Digest morality tales, and the like. Confusing the proles with actual science and plots about people facing the unknown might cause the ratings to drop. > Niven's Ringworld is actually a lot more modest, in that spin provides >the gravity, building materials are disproportionately reduced, and >stresses less, if my sense of the moment is right. You'll find it needs an almost impossibly strong material to hold together. Also, it requires Magic Gravity Generators(tm) because the ring is not in an actual orbit of its sun. The sun in the middle can "drift around" in relation to the ring. Not a good idea. Niven tried to fix this in _Ringworld Engineers_. >Banks' Orbitals are >even more sensible: at 12 ls diameter, the engineering concerns should be >easier, the building materials required would be even more >disproportinately lower, and a diurnal period (if one insists on this) can >be gotten from the spin as well. Just build a ring of them, and you've >bettered the Ringworld: now that's an exotic situation! Orbitals are very sensible. You can build them on an as-needed basis. They can have a variety of climates and ecosystems to fit the needs of whatever races you pal around with. >Aside: does B5 have nights? Is >there one night, or different bands? There's some kind of central light tube that gets dimmed occasionally, according to a B5 mailing list. >(Will provide numbers on these >structures later, although the sphere shell equation should do the job.) >A Death Star is far easier than either, just because of its tiny size. Of >course, these all abandon the goal of total harvesting of light. If you >want to do this, you should build a tiny Dyson-style sphere with vastly >less material. If you can choose the star to harvest, a white dwarf >should be most productive: much smaller, much hotter. All this stuff has been worked to death in various newsgroups. I think discrete habitats is the way to go. Bank's orbitals are the cat's pajamas, IMHO, and probably the biggest individual structure anyone would bother with. --Stefan -- +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+ ***@***.com ~ s*****s@a*****.***u.edu ~ s******j@**.com http://www.ini.cmu.edu/~sjones/ • ****@**.com 10/08/1996 00:00:000 UTC What I am curious about is where would you get the building materials for making such incredible structures? -- / ****@**.com The Philosopher from Hell http://www.io.com/~tpfh/ \ If Hello Kitty was in Hell, she would redecorate it and turn / / it into a cute and happy Place. -- Carlos May O- / \ Nixon in '96! Because the only good politician, is a dead one / / Only 666 shopping days till Armageddon | Visualize Dead Spammers \ • s******j@**.com 12/08/1996 00:00:000 UTC In article <4umnc0$***@g*****.***u.edu>, Brian McGuinness wrote: >By the way, what are the plasma conduits for? Why would anyone want to pipe >plasma around the ship? >--- Brian Easy answer: The writers and Keepers of the Canon don't know shit from shinola about science. Practical answer: To have something to break down in a accident or combat. Gross answer: The plasma conduits carry *blood* plasma. Because the future trek people are so wimpy, they need constant transfusions of fresh blood to keep from collapsing into a heap of self-pitying slime. Really Gross answer: Oh, never mind. -- +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+ ***@***.com ~ s*****s@a*****.***u.edu ~ s******j@**.com http://www.ini.cmu.edu/~sjones/ • j********o@***.com 08/08/1996 00:00:000 UTC The big boys wouldn't have to fake it! They might build a real Big Structure simply to show they could do it. We can't speculate any better about this than a prehistoric (pre-1492) American Indian could speculate about the World Trade Center project! Imagine how tough it would appear to them: their society simply didn't and couldn't undertake projects of that scale, nor would they have been able to conceive of a need for such a building (this particular building especially illustrates the point: "a Trade... Center?!" they'd puzzle.) A cathedral serves a point just as elusive to such a mind-set, yet these represent the premier building projects of an entire age. Now I find myself defending Freeman Dyson from you! I don't recall poor Larry Niven having anything to do with Trek (tm), but Dyson (and not Olaf Staplegun, neither!) envisioned his sphere as the logical end result of a space-living society which collected ever more of its sun's light. He thought they might then de-orbit and connect all the solar collecting space-habs, whatever, into one solid sphere, which they would make habitable by pulling artificial gravity out of a hat (him requiring it in what is basically a wimpy-tech outlook is silly) and using it to live directly inside of. Actually, you'd want to do this sooner, since by that point your collectors would be really shadowing each other with crossed orbits. Also, were you already using the light for non-habitat purposes, the Dyson sphere would be a very cold place to live! On the other hand, if you can effectively make your net albedo zero, you can maximize the use of the light, instead of allowing half to just reflect away as the Earth does (write your Congressman!) Sure, waste heat must be radiated, I know, but life must go on and this needn't be close to net insolation, i.e., the effective temperature of a non-habitable Dyson Sphere needn't be close to the effective temperature of it's solar radius (as just implied). And I liked that episode: for once they did something astronometrically interesting, with nice effects (blue sky and clouds at the gate only), and it was true to Dyson's conception, at least as I understand it. That's another thing that pisses me off about Wimp Trek: Blunderer: in the opening credits, we have all these neat space settings, but never in the damn episodes! Niven's Ringworld is actually a lot more modest, in that spin provides the gravity, building materials are disproportionately reduced, and stresses less, if my sense of the moment is right. Banks' Orbitals are even more sensible: at 12 ls diameter, the engineering concerns should be easier, the building materials required would be even more disproportinately lower, and a diurnal period (if one insists on this) can be gotten from the spin as well. Just build a ring of them, and you've bettered the Ringworld: now that's an exotic situation! (Don't think they could be connected in any simple way, especially given the somewhat silly goal of natural illumination.) Aside: does B5 have nights? Is there one night, or different bands? (Will provide numbers on these structures later, although the sphere shell equation should do the job.) A Death Star is far easier than either, just because of its tiny size. Of course, these all abandon the goal of total harvesting of light. If you want to do this, you should build a tiny Dyson-style sphere with vastly less material. If you can choose the star to harvest, a white dwarf should be most productive: much smaller, much hotter. I've gotten distracted with more fundamental physics since my last equation-ridden post, although I am working out the generalized problem of building stress: there is no use for columns on a self-gravitating structure, and the shell model (where the many levels simply happen to be concentric) is surely the correct one (i.e., weight divided by inner surface area is the limiting pressure: but the weight is merely that of this shell). The other treatment could probably be shown to be equivalent, with a correct theory of pressure, although it's a dumb way to do the integral. This should make it possible for you to calculate the numbers for a single (non-spinning) Dyson shell just by plugging in the sun's gravity (you'll have to fidlle with the thickness, which affects the weight). Once I get back on the big structure theme, I'll find a general equation which will just give the limits without iterative plugging. Gorno Lordy, I've been making the stupidest spelling mistakes lately: confusing there's, it's and dumb stuff like that! • m*******e@a****.***u.edu 12/08/1996 00:00:000 UTC In response to Gorno: we know a lot more today about fundamental physics than primitive savages of the past did, so the comparison is invalid. We can't yet work out the full details of certain futuristic technologies, but we can set reasonable limits on their capabilities. For example, if someone claims that it is possible to travel freely in five spatial dimensions I can demonstrate that he is wrong by deriving the inverse square law of light, and its equivalent in spaces of two and one dimensions and show that the power of r is one less than the number of spatial dimensions that things can move in (and equal to the number of dimensions in a surface that completely encloses the light source in whatever space you're working in) and that our universe has exactly three "open" spatial dimensions (as opposed to compactified ones). Similarly, it is possible, as you mentioned, to look up the structural strength of various metals and calculate the maximum size of a starship which could withstand, say, a 1/2 g acceleration assuming that the ship is essentially a single crystal of some specified metal. Regarding Dyson spheres, since inverse square law fields (such as gravity) cancel inside a spherical shell, you'd fall into the sun if you lived on the inside. The solution is simply to live on the outside, and place the atmosphere there as well. The inner surface would then be completely free for radiation gathering. Re: Star Trek again, I'd use "subspace radio" transceivers in place of the "Optical Data Network" lines and make the computer a distributed system. We already face problems today with the limited speed with which signals can move from point to point in a computer (the original Cray was designed in compact form to minimize the length of the wires in it) and it makes no sense to send signals at the speed of light when you can send them much faster. Using a distributed system of many individual processors scattered throughout the ship would result in a much more damage tolerant system. You could also detach virus-infected components from the rest of the system if you detected the infection in time. By the way, what are the plasma conduits for? Why would anyone want to pipe plasma around the ship? --- Brian • g*****o@l**.****t.net 13/08/1996 00:00:000 UTC : By the way, what are the plasma conduits for? Why would anyone want to pipe : plasma around the ship? Maybe they use them as primitive Heating system for the ships? Now on the Klingon ships, they have fires in those giant metal drums to keep everybody warm on their starships. That would explain why there is always smoke everywhere. With all the wonders of medicine in Trek, maybe the doctors were all getting bored. They asked the Engineers for a little fun on these starships so they designed these dangerous Plasma Conduits to travel all over the ship. Place like the bar, nursery school and the Photon Torpedo Storage have large conduits traveling through them. So whenver they ships gets involved in a fight, the doctors are guaranteed to have some business when these plasma conduits rupture. --Glen • k******d@d*****i.com 13/08/1996 00:00:000 UTC In article <4u55eb$***@p*******.**o.com>, s******j@**.com (Stefan E. Jones) writes: > > I doubt anyone will build things as big as a Death Star. Unless it's a > giant inflatable designed to scare the bejeezus out of niave young > civilizations. An amusing bit for an SF story. Inflatable armadas ala the phantom army set up in England to fool the Nazis in WWII. -- Doc k******d@d*****i.com I have loved the stars too fondly to be fearful of the night • s******j@**.com 13/08/1996 00:00:000 UTC In article <9608131456592.The_Win-D.*******d@d*****i.com>, Kevin Conod wrote: >In article <4u55eb$***@p*******.**o.com>, s******j@**.com (Stefan E. Jones) >writes: >   >> I doubt anyone will build things as big as a Death Star. Unless it's a   >> giant inflatable designed to scare the bejeezus out of niave young   >> civilizations. >An amusing bit for an SF story. Inflatable armadas ala the phantom army set >up in England to fool the Nazis in WWII. Been done. Cordwainer Smith's "Golden the Ships were. Oh! Oh! Oh!" I thought people would catch my reference. This story also features a "Chronopathic idiot." Pinch him, and he travels through time. -- +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+ ***@***.com ~ s*****s@a*****.***u.edu ~ s******j@**.com http://www.ini.cmu.edu/~sjones/ • g*****o@l**.****t.net 15/08/1996 00:00:000 UTC : This story also features a "Chronopathic idiot." Pinch him, and he travels : through time. Backwards or forward in time? What would happen if you hit him by mistake? That's almost as good as the "Time Bombs" in one episode of Underdog. You set the time where you want to appear at. When the bombs explodes, you wind up there. --Glen "When Polly is in trouble, I'm not slow, it's hip-hip-hip and away I go!!!!" What a character name, Polly Purebreed. • b******c@u*******r.ca 16/08/1996 00:00:000 UTC In Charles Sheffield's _Cold as Ice_ there is reference to an astronomical observation of an object the size of a galaxy. Niven suggested that that might be the largest structure imaginable.