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Kugelblitz (astrophysics)
A kugelblitz is a theoretical astrophysical object predicted by general relativity. It is a concentration of heat, light or radiation so intense that its energy forms an event horizon and becomes self-trapped. In other words, if enough radiation is aimed into a region of space, the concentration of energy can warp spacetime so much that it creates a black hole. This would be a black hole whose original mass–energy was in the form of radiant energy rather than matter , however as soon as it forms, it is indistinguishable from an ordinary Black Hole, meaning there is currently no way to trace the origins of a Black Hole. John Archibald Wheeler's 1955 ''Physical Review'' paper entitled " geons" refers to the kugelblitz phenomena and explores the idea of creating such particles (or toy models of particles) from spacetime curvature. The kugelblitz phenomenon has been considered a possible basis for interstellar engines (drives) for future black hole starships. See also * Beke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theoretical Physics
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena. The advancement of science generally depends on the interplay between experimental studies and theory. In some cases, theoretical physics adheres to standards of mathematical rigour while giving little weight to experiments and observations.There is some debate as to whether or not theoretical physics uses mathematics to build intuition and illustrativeness to extract physical insight (especially when normal experience fails), rather than as a tool in formalizing theories. This links to the question of it using mathematics in a less formally rigorous, and more intuitive or heuristic way than, say, mathematical physics. For example, while developing special relativity, Albert Einstein was concerned wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review
''Physical Review'' is a peer-reviewed scientific journal established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the American Physical Society (APS). The journal is in its third series, and is split in several sub-journals each covering a particular field of physics. It has a sister journal, ''Physical Review Letters'', which publishes shorter articles of broader interest. History ''Physical Review'' commenced publication in July 1893, organized by Cornell University professor Edward Nichols and helped by the new president of Cornell, J. Gould Schurman. The journal was managed and edited at Cornell in upstate New York from 1893 to 1913 by Nichols, Ernest Merritt, and Frederick Bedell. The 33 volumes published during this time constitute ''Physical Review Series I''. The American Physical Society (APS), founded in 1899, took over its publication in 1913 and star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Holes
A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. Although it has a great effect on the fate and circumstances of an object crossing it, it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly. Objects whose gravitational fields are too strong for light to escape were first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micro Black Hole
Micro black holes, also called mini black holes or quantum mechanical black holes, are hypothetical tiny (<1 ) , for which effects play an important role. The concept that black holes may exist that are smaller than was introduced in 1971 by Stephen Hawking. It is possible that such black holes were created in the high-density environment of the earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ronald Mallett
Ronald Lawrence Mallett (born March 30, 1945) is an American theoretical physicist, academic and author. He has been a faculty member of the University of Connecticut since 1975 and is best known for his scientific position on the possibility of time travel. Early life and education Mallett was born in Roaring Spring, Pennsylvania, on March 30, 1945, and grew up in The Bronx in New York City. When he was 10 years old, his father died at age 33 of a heart attack, which made him depressed and devastated. About one year later, at age 11, Mallett found a ''Classics Illustrated'' comic book version of H.G. Wells' ''The Time Machine''. Inspired by this literature, he resolved to travel back in time to save his father. This idea became a lifelong obsession and the basis of his research into time travel. Mallett served in the United States Air Force for four years, during the Vietnam War. He returned to civilian life in 1966. This was the year that the science fiction TV series '' Star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bekenstein Bound
In physics, the Bekenstein bound (named after Jacob Bekenstein) is an upper limit on the thermodynamic entropy ''S'', or Shannon entropy ''H'', that can be contained within a given finite region of space which has a finite amount of energy—or conversely, the maximal amount of information required to perfectly describe a given physical system down to the quantum level. It implies that the information of a physical system, or the information necessary to perfectly describe that system, must be finite if the region of space and the energy are finite. In computer science this implies that non-finite models such as Turing machines are not realizable as finite devices. Equations The universal form of the bound was originally found by Jacob Bekenstein in 1981 as the inequality : S \leq \frac, where ''S'' is the entropy, ''k'' is the Boltzmann constant, ''R'' is the radius of a sphere that can enclose the given system, ''E'' is the total mass–energy including any rest masses, ''ħ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The British Interplanetary Society
The ''Journal of the British Interplanetary Society'' (''JBIS'') is a monthly peer-reviewed scientific journal that was established in 1934. The journal covers research on astronautics and space science and technology, including spacecraft design, nozzle theory, launch vehicle design, mission architecture, space stations, lunar exploration, spacecraft propulsion, robotic and manned exploration of the solar system, interstellar travel, interstellar communications, extraterrestrial intelligence, philosophy, and cosmology. It is published monthly by the British Interplanetary Society. History The journal was established in 1934 when the British Interplanetary Society was founded. The inaugural editorial stated: ''The ultimate aim of the society, of course, is the conquest of space and thence interplanetary travel.....(the) immediate task is the stimulation of public interest in the subject of interplanetary travel and the dissemination of knowledge concerning the true nature of the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hole Starship
In astronautics, a black hole starship is the theoretical concept of a starship capable of interstellar travel using a black hole as an energy source for spacecraft propulsion. The concept was first discussed in science fiction, notably in the book ''Imperial Earth'' by Arthur C. Clarke, and in the work of Charles Sheffield, in which energy extracted from a Kerr–Newman black hole is described as powering the rocket engines in the story "Killing Vector" (1978). In a more detailed analysis, a proposal to create an artificial black hole and using a parabolic reflector to reflect its Hawking radiation was discussed in 2009 by Louis Crane and Shawn Westmoreland.Louis Crane and Shawn Westmoreland,Are Black Hole Starships Possible (ArXiv preprint 12 Aug 2009). Retrieved 7 April 2017. Their conclusion was that it was on the edge of possibility, but that quantum gravity effects that are presently unknown will either make it easier, or make it impossible. Similar concepts were also sketc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toy Model
In the modeling of physics, a toy model is a deliberately simplistic model with many details removed so that it can be used to explain a mechanism concisely. It is also useful in a description of the fuller model. * In "toy" mathematical models, this is usually done by reducing or extending the number of dimensions or reducing the number of fields/variables or restricting them to a particular symmetric form. * In Macroeconomics modelling, are a class of models, some may be only loosely based on theory, others more explicitly so. But they have the same purpose. They allow for a quick first pass at some question, and present the essence of the answer from a more complicated model or from a class of models. For the researcher, they may come before writing a more elaborate model, or after, once the elaborate model has been worked out. Blanchard list of examples includes IS–LM model, the Mundell–Fleming model, the RBC model, and the New Keynesian model. * In "toy" physical descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geon (physics)
In theoretical general relativity, a geon is a nonsingular electromagnetic or gravitational wave which is held together in a confined region by the gravitational attraction of its own field energy. They were first investigated theoretically in 1955 by J. A. Wheeler, who coined the term as a contraction of "gravitational electromagnetic entity". Overview Since general relativity is a classical field theory, Wheeler's concept of a geon does not treat them as quantum-mechanical entities, and this generally remains true today. Nonetheless, Wheeler speculated that there might be a relationship between geons and elementary particles. This idea continues to attract some attention among physicists, but in the absence of a viable theory of quantum gravity, the accuracy of this speculative idea cannot be tested. Wheeler did not present explicit geon solutions to the vacuum Einstein field equation, a gap which was partially filled by Brill and Hartle in 1964 by the Brill–Hartle geon. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Archibald Wheeler
John Archibald Wheeler (July 9, 1911April 13, 2008) was an American theoretical physicist. He was largely responsible for reviving interest in general relativity in the United States after World War II. Wheeler also worked with Niels Bohr in explaining the basic principles behind nuclear fission. Together with Gregory Breit, Wheeler developed the concept of the Breit–Wheeler process. He is best known for popularizing the term "black hole," as to objects with gravitational collapse already predicted during the early 20th century, for inventing the terms "quantum foam", "neutron moderator", "wormhole" and "it from bit", and for hypothesizing the "one-electron universe". Stephen Hawking referred to him as the "hero of the black hole story". Wheeler earned his doctorate at Johns Hopkins University under the supervision of Karl Herzfeld, and studied under Breit and Bohr on a National Research Council fellowship. During 1939 he collaborated with Bohr to write a series of papers ... [...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 gravitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
