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Roman Ring
In general relativity, a Roman ring (proposed by Matt Visser in 1997 and named after the Roman arch, a concept proposed by Mike Morris and Kip Thorne in 1988 and named after physicist Tom Roman) is a configuration of wormholes where no subset of wormholes is near to chronology violation, though the combined system can be arbitrarily close to chronology violation. Examples For example, an Earth–Moon wormhole whose far end is 0.5 seconds in the "past" will not violate causality, since information sent to the far end via the wormhole and back through normal space will still arrive back on Earth (-0.5 + 1) = 0.5 seconds after it was transmitted; but an additional wormhole in the other direction will allow information to arrive back on Earth 1 second ''before'' it was transmitted (time travel). However, it is believed that relative time between the transmission of the information in one wormhole throat and out the other end in a ring structure will remain the same, because light wou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the ' is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations. Newton's law of universal gravitation, which describes classical gravity, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass distributions. Some predictions of general relativity, however, are beyond Newton's law of universal gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information
Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level information pertains to the interpretation of that which may be sensed. Any natural process that is not completely random, and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artifacts such as analog signals, poems, pictures, music or other sounds, and currents convey information in a more continuous form. Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation. Information is often processed iteratively: Data available at one step are processed into information to be interpreted and processed at the next step. For example, in written text each symbol or letter conveys information relevant to the word it is part of, each word conveys information rele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the ' is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations. Newton's law of universal gravitation, which describes classical gravity, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass distributions. Some predictions of general relativity, however, are beyond Newton's law of universal gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Ring With Four Wormholes
Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *'' Epistle to the Romans'', shortened to ''Romans'', a letter in the New Testament of the Christian Bible Roman or Romans may also refer to: Arts and entertainment Music * Romans (band), a Japanese pop group * ''Roman'' (album), by Sound Horizon, 2006 * ''Roman'' (EP), by Teen Top, 2011 *" Roman (My Dear Boy)", a 2004 single by Morning Musume Film and television * Film Roman, an American animation studio * ''Roman'' (film), a 2006 American suspense-horror film * ''Romans'' (2013 film), an Indian Malayalam comedy film * ''Romans'' (2017 film), a British drama film * ''The Romans'' (''Doctor Who''), a serial in British TV series People *Roman (given name), a given name, including a list of people and fictional characters *Roman (surname), including a list of people named Roman or Romans *Ῥωμ� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Ring With Two Wormholes
Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *'' Epistle to the Romans'', shortened to ''Romans'', a letter in the New Testament of the Christian Bible Roman or Romans may also refer to: Arts and entertainment Music * Romans (band), a Japanese pop group * ''Roman'' (album), by Sound Horizon, 2006 * ''Roman'' (EP), by Teen Top, 2011 *" Roman (My Dear Boy)", a 2004 single by Morning Musume Film and television * Film Roman, an American animation studio * ''Roman'' (film), a 2006 American suspense-horror film * ''Romans'' (2013 film), an Indian Malayalam comedy film * ''Romans'' (2017 film), a British drama film * ''The Romans'' (''Doctor Who''), a serial in British TV series People *Roman (given name), a given name, including a list of people and fictional characters *Roman (surname), including a list of people named Roman or Romans *Ῥωμ� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Ring With One Wormhole
Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *'' Epistle to the Romans'', shortened to ''Romans'', a letter in the New Testament of the Christian Bible Roman or Romans may also refer to: Arts and entertainment Music * Romans (band), a Japanese pop group * ''Roman'' (album), by Sound Horizon, 2006 * ''Roman'' (EP), by Teen Top, 2011 *" Roman (My Dear Boy)", a 2004 single by Morning Musume Film and television * Film Roman, an American animation studio * ''Roman'' (film), a 2006 American suspense-horror film * ''Romans'' (2013 film), an Indian Malayalam comedy film * ''Romans'' (2017 film), a British drama film * ''The Romans'' (''Doctor Who''), a serial in British TV series People *Roman (given name), a given name, including a list of people and fictional characters *Roman (surname), including a list of people named Roman or Romans *Ῥωμ� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Gravity
Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics; it deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the vicinity of black holes or similar compact astrophysical objects, such as neutron stars. Three of the four fundamental forces of physics are described within the framework of quantum mechanics and quantum field theory. The current understanding of the fourth force, gravity, is based on Albert Einstein's general theory of relativity, which is formulated within the entirely different framework of classical physics. However, that description is incomplete: describing the gravitational field of a black hole in the general theory of relativity leads physical quantities, such as the spacetime curvature, to diverge at the center of the black hole. This signals the breakdown of the general theory of relativity and the need for a theory that goe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronology Protection Conjecture
The chronology protection conjecture is a hypothesis first proposed by Stephen Hawking that laws of physics beyond those of standard general relativity prevent time travel on all but microscopic scales - even when the latter theory states that it should be possible (such as in scenarios where faster than light travel is allowed). The permissibility of time travel is represented mathematically by the existence of closed timelike curves in some solutions to the field equations of general relativity. The chronology protection conjecture should be distinguished from chronological censorship under which every closed timelike curve passes through an event horizon, which might prevent an observer from detecting the causal violation (also known as chronology violation). Etymology In a 1992 paper, Hawking uses the metaphorical device of a "Chronology Protection Agency" as a personification of the aspects of physics that make time travel impossible at macroscopic scales, thus apparently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiclassical Gravity
Semiclassical gravity is the approximation to the theory of quantum gravity in which one treats matter fields as being quantum and the gravitational field as being classical. In semiclassical gravity, matter is represented by quantum matter fields that propagate according to the theory of quantum fields in curved spacetime. The spacetime in which the fields propagate is classical but dynamical. The curvature of the spacetime is given by the ''semiclassical Einstein equations'', which relate the curvature of the spacetime, given by the Einstein tensor G_, to the expectation value of the energy–momentum tensor operator, T_, of the matter fields: : G_ = \frac \left\langle \hat T_ \right\rangle_\psi where ''G'' is the gravitational constant and \psi indicates the quantum state of the matter fields. Stress–energy tensor There is some ambiguity in regulating the stress–energy tensor, and this depends upon the curvature. This ambiguity can be absorbed into the cosmological c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Causality
Causality (also referred to as causation, or cause and effect) is influence by which one event, process, state, or object (''a'' ''cause'') contributes to the production of another event, process, state, or object (an ''effect'') where the cause is partly responsible for the effect, and the effect is partly dependent on the cause. In general, a process has many causes, which are also said to be ''causal factors'' for it, and all lie in its past. An effect can in turn be a cause of, or causal factor for, many other effects, which all lie in its future. Some writers have held that causality is metaphysically prior to notions of time and space. Causality is an abstraction that indicates how the world progresses. As such a basic concept, it is more apt as an explanation of other concepts of progression than as something to be explained by others more basic. The concept is like those of agency and efficacy. For this reason, a leap of intuition may be needed to grasp it. According ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matt Visser
Matt Visser is a mathematics Professor at Victoria University of Wellington, in New Zealand. Work Visser's research interests include general relativity, quantum field theory and cosmology. Visser has produced a large number of research papers on the subject of wormholes, gravitational horizons and notably the emerging subject of acoustic metrics. He is the author of the reference book on the current state of wormhole theory, ''Lorentzian Wormholes — from Einstein to Hawking'' (1996) and co-editor of ''Artificial Black Holes'' (2002). Books *David L Wiltshire, Matt Visser & Susan Scott''The Kerr Spacetime: Rotating black holes in general relativity'' (2009) *M Novello, Matt Visser & G E Volovik''Artificial Black Holes'' (2002) *Matt Visser''Lorentzian Wormholes: From Einstein To Hawking'' (1995) See also * Roman ring In general relativity, a Roman ring (proposed by Matt Visser in 1997 and named after the Roman arch, a concept proposed by Mike Morris and Kip Thorne in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
