Ringworld (A Del Rey book)

"I myself have dreamed up an intermediate step between Dyson Spheres and planets. Build a ring ninety three million miles in radius-one Earth orbit-which would make it six hundred million miles long. If we have the mass of Jupiter to work with, and if we make it a million miles wide, we get a thickness of about a thousand meters. The Ringworld would thus be much sturdier than a Dyson sphere. "There are other advantages. We can spin it for gravity. A rotation on its axis of seven hundred seventy miles per second would give the Ringworld one gravity outward. We wouldn't even have to have a roof over it. Put walls a thousand miles high at each rim, aim it at the sun, and very little air will leak over the edges. "The thing is roomy enough: three million times the area of the Earth. It will be some time before anyone complains of the crowding." -Larry Niven.Larry Niven is the author of 'Ringworld (A Del Rey book)', published 1985 under ISBN 9780345333926 and ISBN 0345333926.