A Dyson sphere is a hypothetical megastructure that encompasses a star and captures a large percentage of its solar power output. The concept is a thought experiment that attempts to imagine how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Because only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy.
Known Space is the fictional setting of about a dozen science fiction novels and several collections of short stories by American writer Larry Niven. It has also become a shared universe in the spin-off Man-Kzin Wars anthologies. The Internet Speculative Fiction Database (ISFDB) catalogs all works set in the fictional universe that includes Known Space under the series name Tales of Known Space, which was the title of a 1975 collection of Niven's short stories. The first-published work in the series, which was Niven's first published piece, was "The Coldest Place", in the December 1964 issue of If magazine, edited by Frederik Pohl. This was the first-published work in the 1975 collection.
Ringworld is a 1970 science fiction novel by Larry Niven, set in his Known Space universe and considered a classic of science fiction literature. Ringworld tells the story of Louis Wu and his companions on a mission to the Ringworld, a rotating wheel artificial world, an alien construct in space 186 million miles in diameter. Niven later added three sequel novels and then cowrote, with Edward M. Lerner, four prequels and a final sequel; the five latter novels constitute the Fleet of Worlds series. All the novels in the Ringworld series tie into numerous other books set in Known Space. Ringworld won the Nebula Award in 1970, as well as both the Hugo Award and Locus Award in 1971.
A space habitat is a more advanced form of living quarters than a space station or habitation module, in that it is intended as a permanent settlement or green habitat rather than as a simple way-station or other specialized facility. No space habitat has been constructed yet, but many design concepts, with varying degrees of realism, have come both from engineers and from science-fiction authors.
Orion's Arm is a multi-authored online science fiction world-building project, first established in 2000 by M. Alan Kazlev, Donna Malcolm Hirsekorn, Bernd Helfert and Anders Sandberg and further co-authored by many people since. Anyone can contribute articles, stories, artwork, or music to the website. A large mailing list exists, in which members debate aspects of the world they are creating, discussing additions, modifications, issues arising, and work to be done.
Star lifting is any of several hypothetical processes by which a sufficiently advanced civilization could remove a substantial portion of a star's matter which can then be re-purposed, while possibly optimizing the star's energy output and lifespan at the same time. The term appears to have been coined by David Criswell.
An Alderson disk is a hypothetical artificial astronomical megastructure, like Larry Niven's Ringworld and the Dyson sphere. The disk is a giant platter with a thickness of several thousand miles. The Sun rests in the hole at the center of the disk. The outer perimeter of an Alderson disk would be roughly equivalent to the orbit of Mars or Jupiter. According to the proposal, a sufficiently large disk would have a larger mass than its Sun.
Megascale engineering is a form of exploratory engineering concerned with the construction of structures on an enormous scale. Typically these structures are at least 1,000 km (620 mi) in length—in other words, at least one megameter, hence the name. Such large-scale structures are termed megastructures.
An orbital ring is a concept of an artificial ring placed around a body and set rotating at such a rate that the apparent centrifugal force is large enough to counteract the force of gravity. For the Earth, the required speed is on the order of 10 km/sec, compared to a typical low Earth orbit velocity of 8 km/sec. The structure is intended to be used as a space station or as a planetary vehicle for very high-speed transportation or space launch.
Globus Cassus is an art project and book by Swiss architect and artist Christian Waldvogel presenting a conceptual transformation of planet Earth into a much bigger, hollow, artificial world with an ecosphere on its inner surface. It was the Swiss contribution to the 2004 Venice Architecture Biennale and was awarded the gold medal in the category "Most beautiful books of the World" at the Leipzig Book Fair in 2005. It consists of a meticulous description of the transformation process, a narrative of its construction, and suggestions on the organizational workings on Globus Cassus.
Stellar engineering is a type of engineering concerned with creating or modifying stars through artificial means.
A rotating wheel space station, also known as a von Braun wheel, is a concept for a hypothetical wheel-shaped space station. Originally proposed by Konstantin Tsiolkovsky in 1903, the idea was expanded by Herman Potočnik in 1929.
The Halo video game and media franchise takes place in a science fiction universe. In the distant past, a race known as the Forerunners fought the parasitic Flood. The Forerunners ultimately activate weapons of mass destruction, the Halo Array, in order to starve the Flood and stop the threat. By the 26th century, humanity, led by the United Nations Space Command (UNSC), is caught in a war with an alien coalition known as the Covenant. The Covenant worship the Forerunners as deities, mistakenly believing that the Halos are a tool of salvation, not destruction. The Flood, meanwhile, escape the confines of Halo and threaten to spread across the galaxy again.
Non-rocket spacelaunch refers to theoretical concepts for launch into space where much of the speed and altitude needed to achieve orbit is provided by a propulsion technique that is not subject to the limits of the rocket equation. Although all space launches to date have been rockets, a number of alternatives to rockets have been proposed. In some systems, such as a combination launch system, skyhook, rocket sled launch, rockoon, or air launch, a portion of the total delta-v may be provided, either directly or indirectly, by using rocket propulsion.
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object. It may also describe other motions such as precession or nutation of an object's rotational axis. Prograde or direct motion is more normal motion in the same direction as the primary rotates. However, "retrograde" and "prograde" can also refer to an object other than the primary if so described. The direction of rotation is determined by an inertial frame of reference, such as distant fixed stars.
A Bishop Ring is a type of hypothetical rotating space habitat originally proposed in 1997 by Forrest Bishop of the Institute of Atomic-Scale Engineering. The concept is a smaller scale version of the Banks Orbital, which itself is a smaller version of the Niven ring. Like other space habitat designs, the Bishop Ring would spin to produce artificial gravity by way of centrifugal force. The design differs from the classical designs produced in the 1970s by Gerard K. O'Neill and NASA in that it would use carbon nanotubes instead of steel, allowing the habitat to be built much larger. In the original proposal, the habitat would be approximately 1,000 km (620 mi) in radius and 500 km (310 mi) in width, containing 3 million square kilometers of living space, comparable to the area of Argentina or India.
Engineering on an astronomical scale, or astronomical engineering, i.e., engineering involving operations with whole astronomical objects, is a known theme in science fiction, as well as a matter of recent scientific research and exploratory engineering.
An O'Neill cylinder is a space settlement concept proposed by American physicist Gerard K. O'Neill in his 1976 book The High Frontier: Human Colonies in Space. O'Neill proposed the colonization of space for the 21st century, using materials extracted from the Moon and later from asteroids.
"Bigger Than Worlds" is an essay by the American science fiction writer Larry Niven. It was first published in March 1974 in Analog magazine, and 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.
An artificial planet is a proposed stellar megastructure. Its defining characteristic is that it has sufficient mass to generate its own gravity field that is strong enough to prevent atmosphere from escaping, although the term has been sometimes used to describe other types of megastructures that have self-sufficient ecosystems. The concept can be found in many works of science-fiction.
