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Revision as of 17:22, 9 June 2004 by Opus33 (talk | contribs) (Link to a review)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Ringworld is the title of a science fiction novel by Larry Niven (set in his Known Space universe) in which four explorers, two humans and two aliens of different species, set out to explore an enormous artificial world 200 light years from Earth.
The work is widely considered one of the classics of the science fiction literature. It stands out for its vividly drawn characters. The protagonist Louis Wu is very old (but physically perfectly preserved), bored with life, and consequently ready for adventure. Speaker-To-Animals is a Kzin (a ferocious predator species), and his persona seems to be modeled on a Japanese samurai warrior. Nessus, a Pierson's Puppeteer, belongs to a species whose most notable trait is cowardice; it only emerges slowly that Nessus and his conspecifics are largely in control of the action. Teela Brown is introduced as a female "airhead" character, but turns out to be rather more interesting as the plot proceeds.
Ringworld engineering
The "Ringworld" is an artificial ring about a million miles wide and approximately the diameter of Earth's orbit (which makes it about 600 million miles in circumference), centered about a star, and rotating to provide an Earthlike artificial gravity, with a habitable flat inner surface equivalent in area to approximately three million Earth-sized planets. Walls 1000 miles tall along the edges keep in the atmosphere. The Ringworld could be regarded as a thin slice of a Dyson sphere, with which it shares a number of characteristics.
"Ringworld" has become a generic term for such a structure, which is an exemplar of what science fiction fans call a "Big Dumb Object". Other science fiction authors have devised their own variants of Niven's Ringworld, notably Iain M. Banks' Culture Orbitals, best described as miniature Ringworlds.
The construction of a ringworld remains firmly in the area of science fictional speculation, since although if such a structure was built, it could indeed provide a huge habitable inner surface, the energy required to construct and set it rotating is so massive (several centuries' worth of the total energy output from the Sun) that without as-yet unimagined energy sources becoming available, it is hard to see how this construction could ever be possible. Furthermore, the tensile strength of the material required would be on the same order as the strong nuclear force; nothing even remotely strong enough is known to exist in nature. In Niven's Ringworld novels, the material - which he calls scrith - is said to have been artificially produced through the transmutation of matter into the required substance. Quite how this was achieved is (probably wisely) never clearly explained, leaving scrith firmly in the category of unobtainium.
Additionally, a ringworld design requires active stabilization, because it is not in inertial orbit. Though the ring itself is rotating at 1200 km/s (to approximate Earth gravity), the center of mass does not move at all. Large thrusters must be incorporated into the design to keep it centered about its star. This point gave Niven some difficulty after he published his first Ringworld novel; he was deluged with letters pointing out that "the Ringworld isn't stable" and dedicated the first sequel to a resolution of this problem.
To provide an approximation of the day/night cycle common to planets, Niven's Ringworld was also provided with a separate ring of "shadow squares" linked together (by "shadow square wires") in a ring close to the star. These absorb a huge amount of sunlight energy, which is beamed to the Ringworld as its primary source of power. They are also not in inertial orbit, and must be actively stabilized as well.
Sequels and adaptations
The novel Ringworld has been followed by two sequels, The Ringworld Engineers and The Ringworld Throne. A fourth book, Ringworld's Children appeared in the USA in June 2004.
In the 1980s a role-playing game based on this setting was produced by Chaosium named RingworldRPG.
The plot of the first-person shooter Halo for the Microsoft Xbox also takes place on a ringworld, though with no reference to the Niven novel - given its dimensions (some 50,000 miles across) it is more like Banks' Culture Orbitals than Niven's behemoth.