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Bigger Than Worlds
"Bigger Than Worlds" is an essay by the American science fiction writer Larry Niven (born 1938). 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. Sections After an introduction saying that everyone may not always live on a single planet, the essay is divided into (mostly short) sections having the following titles and brief descriptions: ; The Multi-Generation Ship A generation ship is a slower-than-light spaceship housing some hundreds of people which takes several human generations to complete its journey. It could in principle be built using known technology. ; 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 hol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essay
An essay is, generally, a piece of writing that gives the author's own argument, but the definition is vague, overlapping with those of a letter, a paper, an article, a pamphlet, and a short story. Essays have been sub-classified as formal and informal: formal essays are characterized by "serious purpose, dignity, logical organization, length," whereas the informal essay is characterized by "the personal element (self-revelation, individual tastes and experiences, confidential manner), humor, graceful style, rambling structure, unconventionality or novelty of theme," etc. Essays are commonly used as literary criticism, political manifestos, learned arguments, observations of daily life, recollections, and reflections of the author. Almost all modern essays are written in prose, but works in verse have been dubbed essays (e.g., Alexander Pope's ''An Essay on Criticism'' and '' An Essay on Man''). While brevity usually defines an essay, voluminous works like John Locke's ''An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Novel Sequence
A book series is a sequence of books having certain characteristics in common that are formally identified together as a group. Book series can be organized in different ways, such as written by the same author, or marketed as a group by their publisher. Publishers' reprint series Reprint series of public domain fiction (and sometimes nonfiction) books appeared as early as the 18th century, with the series ''The Poets of Great Britain Complete from Chaucer to Churchill'' (founded by British publisher John Bell in 1777). In 1841 the German Tauchnitz publishing firm launched the ''Collection of British and American Authors'', a reprint series of inexpensive paperbound editions of both public domain and copyrighted fiction and nonfiction works. This book series was unique for paying living authors of the works published even though copyright protection did not exist between nations in the 19th century. Later British reprint series were to include the ''Routledge's Railway Library ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torus
In geometry, a torus (plural tori, colloquially donut or doughnut) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis that is coplanar with the circle. If the axis of revolution does not touch the circle, the surface has a ring shape and is called a torus of revolution. If the axis of revolution is tangent to the circle, the surface is a horn torus. If the axis of revolution passes twice through the circle, the surface is a spindle torus. If the axis of revolution passes through the center of the circle, the surface is a degenerate torus, a double-covered sphere. If the revolved curve is not a circle, the surface is called a ''toroid'', as in a square toroid. Real-world objects that approximate a torus of revolution include swim rings, inner tubes and ringette rings. Eyeglass lenses that combine spherical and cylindrical correction are toric lenses. A torus should not be confused with a '' solid torus'', which is formed by r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topopolis
A topopolis is a proposed tube-shaped space habitat, rotating to produce artificial gravity via centrifugal force on the inner surface, which is extended into a loop around the local planet or star. The concept was invented by writer Patrick Gunkel. Varieties of topopolises and similar fictional structures A topopolis has been compared to an O'Neill cylinder, or a McKendree cylinder, that has been extended in length so that it encircles a star. A “normal” topopolis would be hundreds of millions of miles/kilometers long and at least several miles (kilometers) in diameter. Topopoles can be looped several times around the local star, in a geometric figure known as a torus knot. Topopolises are also called cosmic spaghetti. A topopolis with big enough diameter could theoretically have multiple levels of concentric cylinders. Larry Niven (1974) mentioned the idea in a much-reprinted magazine article "Bigger Than Worlds". Examples in novels Iain M. Banks (2008) depicts a topo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discworld (world)
The Discworld is the fictional setting for all of Terry Pratchett's ''Discworld'' fantasy novels. It consists of a large disc (complete with edge-of-the-world drop-off and consequent waterfall) resting on the backs of four huge elephants which are in turn standing on the back of an enormous turtle, named Great A'Tuin (similar to Chukwa or Akupara from Hindu mythology) as it slowly swims through space. The Disc has been shown to be heavily influenced by magic and, while Pratchett gave it certain similarities to planet Earth, he also created his own system of physics for it. Pratchett first explored the idea of a disc-shaped world in the novel ''Strata'' (1981). Great A'Tuin Great A'Tuin is the Giant Star Turtle (of the fictional species ''Chelys galactica'') who travels through the Discworld universe's space, carrying four giant elephants (named Berilia, Tubul, Great T'Phon, and Jerakeen) who in turn carry the Discworld. The narration has described A'Tuin as "the only turtle ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terry Pratchett
Sir Terence David John Pratchett (28 April 1948 – 12 March 2015) was an English humourist, satirist, and author of fantasy novels, especially comical works. He is best known for his ''Discworld'' series of 41 novels. Pratchett's first novel, ''The Carpet People'', was published in 1971. The first ''Discworld'' novel, ''The Colour of Magic'', was published in 1983, after which Pratchett wrote an average of two books a year. The final ''Discworld'' novel, ''The Shepherd's Crown'', was published in August 2015, five months after his death. With more than 85 million books sold worldwide in 37 languages, Pratchett was the UK's best-selling author of the 1990s. He was appointed Officer of the Order of the British Empire (OBE) in 1998 and was knighted for services to literature in the 2009 New Year Honours. In 2001 he won the annual Carnegie Medal for ''The Amazing Maurice and his Educated Rodents'', the first ''Discworld'' book marketed for children. He received the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth the mass of the Sun. Jupiter is the List of brightest natural objects in the sky, third brightest natural object in the Earth's night sky after the Moon and Venus, and it has been observed since Pre-history, prehistoric times. It was named after the Jupiter (mythology), Roman god Jupiter, the king of the gods. Jupiter is primarily composed of hydrogen, but helium constitutes one-quarter of its mass and one-tenth of its volume. It probably has a rocky core of heavier elements, but, like the other giant planets in the Solar System, it lacks a well-defined solid surface. The ongoing contraction of Jupiter's interior generates more heat than it receives from the Sun. Because of its rapid rotation, the planet' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos (moon), Phobos and Deimos (moon), Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and List of tallest mountains in the Solar System, highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The North Polar Basin (Mars), Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alderson Disk
An Alderson disk (named after Dan Alderson, its originator) 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. The hole would be surrounded by a thousand-mile-high wall to prevent the atmosphere from drifting into the Sun. The outer rim would take care of itself. The mechanical stresses within the disc would be far beyond what any known material can stand, thus relegating such a structure to the realm of exploratory engineering until materials and construction science become sufficiently advanced. Building a megastructure of this magnitude would require an amount of material that far surpasses the amount of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Fall
In Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it. An object in the technical sense of the term "free fall" may not necessarily be falling down in the usual sense of the term. An object moving upwards might not normally be considered to be falling, but if it is subject to only the force of gravity, it is said to be in free fall. The Moon is thus in free fall around the Earth, though its orbital speed keeps it in very far orbit from the Earth's surface. In a roughly uniform gravitational field gravity acts on each part of a body approximately equally. When there are no other forces, such as the normal force exerted between a body (e.g. an astronaut in orbit) and its surrounding objects, it will result in the sensation of weightlessness, a condition that also occurs when the gravitati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ringworld
''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 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. Plot summary On planet Earth in 2850 AD, Louis Gridley Wu is celebrating his 200th birthday. Despite his age, Louis is in perfect physical condition due to the longevity drug boosterspice. He meets Nessus, a Pierson's puppeteer, who offers him a mysterious job. Intrigued, Louis eventually accepts. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyson Sphere
A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its solar power output. The concept is a thought experiment that attempts to explain 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. The first contemporary description of the structure was by Olaf Stapledon in his science fiction novel '' Star Maker'' (1937), in which he described "every solar system... surrounded by a gauze of light-traps, which focused the escaping solar energy for intelligent use". The concept was later popularized by Freeman Dyson in his 1960 paper "Search for Artificial Stellar Sources of Infrared Radiation". Dyson speculated that such stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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