Megastructures
Info
All text is from Wikipedia.
Planetary scale
A Bishop Ring, Halo, or Orbital is a space habitat similar to but much smaller than a Niven Ring. Instead of being centered on a star, it is in orbit around the star and its diameter is typically on the order of magnitude of a planet. By tilting the ring relative to its orbit, the inner surface would experience a nearly conventional day and night cycle. Due to its enormous scale, the habitat would not need to be fully enclosed like the Stanford Torus, instead its atmosphere would be retained solely by centripetal gravity and side walls, allowing an open sky.
Stellar scale
Dyson Sphere
A Dyson sphere (also known as a Dyson shell) refers to a structure or mass of orbiting objects that completely surrounds a star to make full use of its solar energy.
Dyson swarm
A Dyson swarm is a Dyson sphere made up of separately orbiting elements (including large habitats) rather than a single continuous shell.
Dyson bubble
A Dyson bubble is a Dyson sphere in which the individual elements are statites, non-orbital objects held aloft by the pressure of sunlight.
Matrioshka brain
A Matrioshka brain is a collection of multiple Concentric Dyson Spheres which make use of star’s energy for computing.
Alderson disk
The Alderson disk is a theoretical structure in the shape of a disk, whose outer radius is equivalent to the orbit of Mars or Jupiter and whose thickness is several thousand miles. A civilization could live on either side, held by the gravity of the disk and still receive sunlight from a star bobbing up and down in the middle of the disk.
Stellar engine
A Stellar engine either uses the temperature difference between a star and interstellar space to extract energy or serves as a Shkadov thruster.
Shkadov thruster
Topopolis
Topopolis (also known as Cosmic Spaghetti) is a large tube that rotates to provide artificial gravity.
Ringworld
A Ringworld (or Niven Ring) is an artificial ring encircling a star, rotating faster than orbital velocity to create artificial gravity on its inner surface. A non-rotating variant is a transparent ring of breathable gas, creating a continuous microgravity environment around the star, as in the eponymous Smoke Ring.