Bigger Than Worlds
Niven, Larry. "Bigger Than Worlds." Analog Science Fiction/Science Fact, March 1974. Essay. Richly illustrated. For reprints and other bibliographical information, see Internet Speculative Fiction Database, here.
Listed in Benford and Zebrowski's Skylife: Space Habitats in Story and Science. Summarized in Wikipedia entry, ""Bigger Than Worlds" is an essay by the American science fiction writer Larry Niven (born 1938). It [...] has been anthologized in A Hole in Space (1974) and in Playgrounds of the Mind (1991). It reviews a number of proposals, not inconsistent with the known laws of physics, which have been made for habitable artificial astronomical megastructures."
Sections briefly annotated in Wikipedia article:
The Multi-Generation Ship [...]
Gravity Niven can conceive of four ways of generating artificial gravity in a spaceship: (1) centrifugal force; (2) adding mass, e.g. neutronium or a black hole [...].
Flying Cities These were proposed by James Blish (1921–75) in his novel sequence Cities in Flight (1956–62) [...]. Niven proposes a giant annular spaceship, which rotates to generate artificial gravity.
Inside Outside This describes a hollowed-out planetoid, with living quarters inside.
Macro-Life Any of the foregoing could be made self-sufficient and a permanent habitation [...].
Worlds Niven introduces the concept of engineering and terraforming whole planets.
Dyson Spheres A Dyson sphere is a hollow spherical megastructure that completely encompasses a star. The inside surface is inhabited. The structure need not be a complete sphere; as, for example, in Niven's novel Ringworld (1970). [...]
Dyson Spheres II A Dyson structure could rotate to generate artificial gravity. Alternatively, one could do without gravity and live in free fall by inhabiting the space between two concentric Dyson spheres.
The Disc An Alderson disk is a platter of diameter similar to that of the orbits of Mars or Jupiter, with a star occupying a hole in its center.
Cosmic Macaroni In a topopolis, a star is surrounded by a toroidal tube, which rotates around its internal circular axis to generate artificial gravity by centrifugal force. The structure need not be circular: it could be more complex, consisting of multiple loops around the star.
The Megasphere A Dyson sphere contains the heart of a galaxy. The outside surface is the biosphere; the stars inside the source of energy. Surface gravity is minute, so that ability to live in free fall would be necessary. [...]
Finally, Niven notes that a rotating ringworld equipped with conducting surfaces could set up enormous magnetic forces acting on the star, which could be used to control its burning and to force it to emit a jet of gas along the system's axis. The star would become its own space drive, towing the ringworld along by gravity. [...]
RDE, finishing, 13Jun22