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.[1]

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."[2]

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. [...][3]

RDE, finishing, 13Jun22