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Wahlquist Fluid
In general relativity, the Wahlquist fluid is an exact rotating perfect fluid solution to Einstein's equation with equation of state corresponding to constant gravitational mass density. Introduction The Wahlquist fluid was first discovered by Hugo D. Wahlquist in 1968. It is one of few known exact rotating perfect fluid solutions in general relativity. The solution reduces to the static Whittaker metric in the limit of zero rotation. Metric The metric of a Wahlquist fluid is given by : ds^2=f(dt-\tilded\varphi)^2-r_0^2(\zeta^2+\xi^2) frac+\frac+\fracd\varphi^2 where : f=\frac :\tilde=r_0(\frac-\xi_A^2) :\tilde_1(\zeta)=1+\zeta^2+\frac zeta_+\frac\sqrt\arcsin(\tilde\zeta)/math> :\tilde_2(\xi)=1-\xi^2-\frac xi_-\frac\sqrt\sinh^ (\tilde\xi)/math> and \xi_A is defined by \tilde_2(\xi_A)=0. It is a solution with equation of state \mu+3p=\mu_0 where \mu_0 is a constant. Properties The pressure and density of the Wahlquist fluid are given by :p=\frac\mu_0(1-\kappa^2 f) :\ ... [...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 gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfect Fluid
In physics, a perfect fluid is a fluid that can be completely characterized by its rest frame mass density \rho_m and ''isotropic'' pressure ''p''. Real fluids are "sticky" and contain (and conduct) heat. Perfect fluids are idealized models in which these possibilities are neglected. Specifically, perfect fluids have no shear stresses, viscosity, or heat conduction. Quark–gluon plasma is the closest known substance to a perfect fluid. In space-positive metric signature tensor notation, the stress–energy tensor of a perfect fluid can be written in the form :T^ = \left( \rho_m + \frac \right) \, U^\mu U^\nu + p \, \eta^\, where ''U'' is the 4-velocity vector field of the fluid and where \eta_ = \operatorname(-1,1,1,1) is the metric tensor of Minkowski spacetime. In time-positive metric signature tensor notation, the stress–energy tensor of a perfect fluid can be written in the form :T^ = \left( \rho_\text + \frac \right) \, U^\mu U^\nu - p \, \eta^\, where ''U'' is the 4-v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Einstein's Equation
In the general theory of relativity, the Einstein field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of matter within it. The equations were published by Einstein in 1915 in the form of a tensor equation which related the local ' (expressed by the Einstein tensor) with the local energy, momentum and stress within that spacetime (expressed by the stress–energy tensor). Analogously to the way that electromagnetic fields are related to the distribution of charges and currents via Maxwell's equations, the EFE relate the spacetime geometry to the distribution of mass–energy, momentum and stress, that is, they determine the metric tensor of spacetime for a given arrangement of stress–energy–momentum in the spacetime. The relationship between the metric tensor and the Einstein tensor allows the EFE to be written as a set of nonlinear partial differential equations when used in this way. The solutions of the EFE are th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugo D
Hugo or HUGO may refer to: Arts and entertainment * ''Hugo'' (film), a 2011 film directed by Martin Scorsese * Hugo Award, a science fiction and fantasy award named after Hugo Gernsback * Hugo (franchise), a children's media franchise based on a troll ** ''Hugo'' (game show), a television show that first ran from 1990 to 1995 ** ''Hugo'' (video game), several video games released between 1991 and 2000 * ''Hugo'' (stylised as ''hugo''), a 2022 album by British rapper Loyle Carner People and fictional characters * Victor Hugo, a French poet, novelist, and dramatist of the Romantic movement. * Hugo (name), including lists of people with Hugo as a given name or surname, as well as fictional characters * Hugo (musician), Thai-American actor and singer-songwriter Chulachak Chakrabongse (born 1981) Places in the United States * Hugo, Alabama, an unincorporated community * Hugo, Colorado, a Statutory Town * Hugo, Minnesota, a town * Hugo, Missouri, an unincorporated community * Hu ... [...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] |
Whittaker Metric
Whittaker is a surname of English origin, meaning 'white acre', and a given name. Variants include Whitaker and Whitacre. People with the name include: Surname A *Aaron Whittaker (born 1968), New Zealand rugby player *Al Whittaker (1918–2006), American business organizer *Alison Whittaker, Australian poet *Allien Whittaker (born 1983), Jamaican footballer *Andrew Whittaker (engineer) (born 1956), American engineer *Andy Whittaker, British film distributor *Anthony Whittaker (born 1968), American composer * Arnie Whittaker (1879–1955), English footballer B * Ben Whittaker (born 1989), Australian rugby union footballer *Benjamin Whittaker (born 1997), English boxer * Bernard Whittaker (1865–??), English footballer * Bill Whittaker (other), multiple people *Bob Whittaker (born 1939), American politician *Brian Whittaker (1956–1997), Scottish footballer C * Charles Whittaker (other), multiple people *Craig Whittaker (born 1962), British politician *Cynth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prolate Spheroid
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. If the ellipse is rotated about its major axis, the result is a ''prolate spheroid'', elongated like a rugby ball. The American football is similar but has a pointier end than a spheroid could. If the ellipse is rotated about its minor axis, the result is an ''oblate spheroid'', flattened like a lentil or a plain M&M. If the generating ellipse is a circle, the result is a sphere. Due to the combined effects of gravity and rotation, the figure of the Earth (and of all planets) is not quite a sphere, but instead is slightly flattened in the direction of its axis of rotation. For that reason, in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oblate Spheroid
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. If the ellipse is rotated about its major axis, the result is a ''prolate spheroid'', elongated like a rugby ball. The American football is similar but has a pointier end than a spheroid could. If the ellipse is rotated about its minor axis, the result is an ''oblate spheroid'', flattened like a lentil or a plain M&M. If the generating ellipse is a circle, the result is a sphere. Due to the combined effects of gravity and rotation, the figure of the Earth (and of all planets) is not quite a sphere, but instead is slightly flattened in the direction of its axis of rotation. For that reason, in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical And Quantum Gravity
''Classical and Quantum Gravity'' is a peer-reviewed journal that covers all aspects of gravitational physics and the theory of spacetime. Its scope includes: *Classical general relativity *Applications of relativity *Experimental gravitation *Cosmology and the early universe *Quantum gravity *Supergravity, superstrings and supersymmetry *Mathematical physics relevant to gravitation The editor-in-chief is Gabriela González at Louisiana State University. The 2018 impact factor is 3.487 according to Journal Citation Reports. As of October 2015, the journal publishes letters in addition to regular articles. There was a companion website to the main journal, CQG+ which highlighted high quality papers published in the journal to raise the visibility of those papers. It also featured film reviews related to gravity such as '' Interstellar'' and '' The Theory of Everything ''. ''Classical and Quantum Gravity'' also supports the field of gravitational physics through sponsorsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
