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Halo Science - Ringworlds and Plasma Weapons
The book Halo Effect is an intriguing title that takes a look Bungie's best-selling Halo titles from a number of different angles. Each chapter includes coverage of specific elements; included are descriptions of pro events, a bit on the development process, and the making of the Red vs. Blue series. One of the most interesting chapters takes a look at the science behind the Halo world, talking about the physics and logic behind ringworlds and the hi-tech weaponry seen in the game. Thanks in part to a mini-review of the book on the GameSetWatch site, Gamasutra has been allowed to reprint the entire 'science of Halo' chapter on their website. "A 5,000 kilometer radius would yield a circumference of roughly 31,400 kilometers. If we assume a width-to-radius ratio similar to that of Niven's Ringworld, they would be approximately 5.37 kilometers wide. They are significantly wider, though, at 320 kilometers. The Halos, then, would have a surface area of 10 million square kilometers - slightly larger than the surface area of Canada, and approximately 2 percent of the surface area of Earth. Of course, since we know that there are lakes, seas, and rivers on the Halos, the livable surface area would be fractionally less." Update: 05/02 18:30 GMT by Z : The initial version of the article posted was from pre-production and contained some errors. They've been fixed in the article and now here in the post as well.
I'm far too lazy to read the article, fanboys have all but ruined Halo for me, but does it mention anything about what happens on the edges of the Halo world? Would be really cool if they had a level in Halo near the edge. It's funny how they just kinda ignore that the game takes place on a world that actually has the pre-Columbus world-with-edges setup going on. What happens to the atmosphere (atmocylinder?) at the edge? If you're flying in an aircraft can you fly over the edge given enough momentum? How are the seas held back, etc?
A solid Dyson sphere is just as unstable as a ring, for the exact same reason. Day and night cycles are even more difficult to simulate. And the structural issues are just as insurmountable.
Probably the answer is to abandon a solid surface, but that works as well for a ring as a sphere.
The Halo is not the only science fiction element in the Halo universe, you know. It's just the one it's named after. It also has a pretty unique AI concept (pioneered from the Marathon games, I believe) as well as an interesting alien civilization consisting of different races with a strange and pretty complex social dynamic but all seem to work (more or less) together despite that. Then there's the Flood, which is some sort of super-evolved virus or bacteria.
If you read the novels, they also shove in a bunch of genetic engineering and spacesuit/armor construction and some other stuff.
Plus the Halo in Halo is actually build as an amplifier to some kind of neutron bomb or something which can kill all life in a huge radius.
I'm glad that you can come to Slashdot and show off your knowledge of Niven, but the Halo universe is actually a very well-constructed science fiction universe in its own right.
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Dyson spheres are also unstable, though not drastically so. And, practically speaking, you need a pair of them, concentric (you hold the atmosphere between them. There really WOULD be pillars holding up the sky! And etherial spheres (well, at least one of them). Keeping the sun in the center, however, looks to be a bit tricky, but fortunately the net gravitational instability should be quite small even if the sun is slightly off center (you can't assume that mass is actually symmetrically distributed, only approximately).
Note that as you don't spin a Dyson Sphere, net gravity is very low. About half that of the Sun's from the distance of the Earth. This makes ponds, lakes & seas possible (if not probable, and probably temporary), but quite dangerous. Rivers, however, are not going to occur.
I think we've pushed this "anyone can grow up to be president" thing too far.
When I read Ringworld, I wondered why you wouldn't build something that combined both a ringworld and a Dyson sphere. Let's say the ringworld followed Niven's dimensions. At 1 million miles wide, it only occupies about 1% of the 'latitude' of the orbital sphere. All the solar energy directed elsewhere is wasted.
... but if you have the resources to build the ringworld to begin with, this shouldn't be a stretch.
It seems it would be good to build a smaller sphere that can collect this energy. If you built it at an inner orbit (like Mercury's orbital distance) you wouldn't need as much material. You would leave out a section of the middle that corresponds to the location of the 'ring plane' to allow the energy there to make its way to the ring. Both halves of the sphere could still be connected, but instead of solid sphere, it would be alternating solid/empty to provide the function of the shadow squares. You may want to perforate it in other areas as well to allow solar pressure to escape.
Exactly what materials you'd use, I don't know
Assuming you have enough thrusters, and a good controll program, you could easilly compensate for up to 50-90% of the total thrusters being offline at a time, allowing you to do repairs at your leasure. And a dyson sphere DOESNT HAVE poles, none, its uniformally the same temperature the whole sphere over (minus whatever height differences, as peaks would be a bit colder due to less atmosphere or the bottoms of the oceans which could be a bit colder).
If you spin a dyson sphere, you dont have to simulate gravity, at all, and if the spinning mechanism failed, you would have a LOT of time to deal with it, as it would take a while for something spinning that fast to spin down to a point where people start falling off the surface. Assuming the loss of spin comes from too few functioning thrusters, then you would have an even slower spin-down because the tursters would compensate for the loss, at least a little.
Portals are a staple of most dyson spheres, but with something that big, the odds of having to leave very often are rather unlikely. Even if you did need to leave, reinforced circular portals would be good,it wouldnt compromise the strength of the sphere if it was curved at the same rate, and could be built as needed. Any single LARGE (drive a planet through it) portal could be difficult, but would not be impossible.