Another megastructure would be just a giant enclosed ball of gasabout 100,000 km. in diameter. Up to that size it won't collapse underits own weight, and the space inside the interior is truly huge. Thisstructure would be stable. All kinds of stuff could be put inside rangingin size up to asteroids.

True. And all these light sources would generate an enormous amount of heat,which would have to be gotten rid of. Also one might imagine the wind systemsthat could develop inside these, that would make the strongest hurricane look tame,and tear the thing apart.After posting this idea I started thinking about the above, and wondered whywouldanyone build such a thing in the first place. This however was when it was posteda response to the "supramundane world" megastructure idea which is patently ridiculous.Instead of super-bubble worlds how about just bubble worlds of say 100-800 km across.Sunlight would make it all the way down to the center, which would be like someeternal-sunset world.sailor.barsoom wrote:> You'd have to locate light sources every so many cubic Km.

Cylindricals could be put into these, and so enjoy the best of both worlds.A 100 km large bubble could easily fit several Island Three sized habitats.In _The Millennial Project_ something like this was imagined, like thisimage:http://images4.wikia.nocookie.net/__cb20070426003607/tmp2/images/a/ab/Plate14.jpgsailor.barsoom wrote:> I suppose another question might be: why would anybody want to live in a> zero-G world? But assuming that a large number of people did want to> bubbles in the size range you suggest should do the job just fine. If just a> whole huge lot of people do, they can build a dozen or a thousand of them.I could see these as exotic resort destinations, though. Maybe even with genegineered "wildlife" based on birds, bats, pterosaurs, bugs and fish. Strange "sky sailing" races could be held, and as I mentioned earlier, just about any zero-G sport one cares to imagine. But even that is unlikely to require more than 500 Km or so. Although, I suppose the dimmer parts near the center of a huge one could be where you go for night.

and would have really good radiation and meteoroid shielding

Not to mention the huge amount of nitrogen and oxygen needed to fill it.** volumes **Island Three habitat 1608.5 km3 (8 km diameter x 32 km length)Earth atmosphere 4.2^9 km3Super Bubble world: 5.236^14 km3 (100,000 km diameter)Atmospheric gas required:A super bubble world would have the volume of 374,000 earth atmospheres.At atmospheric density of 1.2 kg/m3, this gas would have a total mass of6.23e23 kg. This would be mostly nitrogen.I'm not sure if there's this much nitrogen in the solar system. Iestimated 2.27e22 kg in the Kuiper Belt, and 1.12e24 kg. in the Oort Cloudback previously. The Oort Cloud mostly lies about 1 light-year out.> True. And all these light sources would generate an enormous amount of heat,> which would have to be gotten rid of. Also one might imagine the wind systems> that could develop inside these, that would make the strongest hurricane look tame,and tear the thing apart.