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List Of Things Named After Stephen Hawking
This is a list of things named after British physicist Stephen Hawking (1942–2018). Physics and mathematics * Bekenstein-Hawking Formula, Bekenstein-Hawking formula for Bekenstein–Hawking entropy, a way to calculate the entropy of a black hole, named after Jacob Bekenstein and Hawking, whose ideas on black hole entropy were combined into the equation. * Gibbons–Hawking ansatz, named Gary Gibbons and Hawking, a method of constructing Gravitational instanton, gravitational instantons. * Gibbons–Hawking–York boundary term, named after Gary Gibbons, James W. York and Hawking. It is a correction to the Einstein–Hilbert action in the presence of a boundary. * Gibbons–Hawking effect, named after Gary Gibbons and Hawking, is the statement that a temperature can be associated to each solution of the Einstein field equations under certain conditions. * Gibbons–Hawking space, named after Gary Gibbons and Hawking, a concept in algebraic geometry. * Hartle–Hawking state an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephen Hawking
Stephen William Hawking (8January 194214March 2018) was an English theoretical physics, theoretical physicist, cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge. Between 1979 and 2009, he was the Lucasian Professor of Mathematics at Cambridge, widely viewed as one of the most prestigious academic posts in the world. Hawking was born in Oxford into a family of physicians. In October 1959, at the age of 17, he began his university education at University College, Oxford, where he received a First Class Honours, first-class Honours degree, BA degree in physics. In October 1962, he began his graduate work at Trinity Hall, Cambridge, where, in March 1966, he obtained his PhD in applied mathematics and theoretical physics, specialising in general relativity and cosmology. In 1963, at age 21, Hawking was diagnosed with an early-onset slow-progressing form of motor neurone disease that gradually, over decades, pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawking Energy
The Hawking energy or Hawking mass is one of the possible definitions of mass in general relativity. It is a measure of the bending of ingoing and outgoing rays of light that are orthogonal to a 2-sphere surrounding the region of space whose mass is to be defined. Definition Let (\mathcal^3, g_) be a 3-dimensional sub-manifold of a relativistic spacetime, and let \Sigma \subset \mathcal^3 be a closed 2-surface. Then the Hawking mass m_H(\Sigma) of \Sigma is defined to be :m_H(\Sigma) := \sqrt\left( 1 - \frac\int_\Sigma H^2 da \right), where H is the mean curvature of \Sigma. Properties In the Schwarzschild metric, the Hawking mass of any sphere S_r about the central mass is equal to the value m of the central mass. A result of Geroch implies that Hawking mass satisfies an important monotonicity condition. Namely, if \mathcal^3 has nonnegative scalar curvature, then the Hawking mass of \Sigma is non-decreasing as the surface \Sigma flows outward at a speed equal to the inv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel 4
Channel 4 is a British free-to-air public broadcast television channel owned and operated by Channel Four Television Corporation. It is state-owned enterprise, publicly owned but, unlike the BBC, it receives no public funding and is funded entirely by its commercial activities, including Television advertisement, advertising. It began its transmission in 1982 and was established to provide a fourth television service in the United Kingdom. At the time, the only other channels were the television licence, licence-funded BBC1 and BBC2, and a single commercial broadcasting network, ITV (TV network), ITV. Originally a subsidiary of the Independent Broadcasting Authority (IBA), the station is now owned and operated by Channel Four Television Corporation, a public corporation of the Department for Culture, Media and Sport, which was established in 1990 and came into operation in 1993. Until 2010, Channel 4 did not broadcast in Wales, but many of its programmes were re-broadcast ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brave New World With Stephen Hawking
''Brave New World with Stephen Hawking'' is a 2011 science documentary television mini-series presented by Professor Stephen Hawking who examines how science is striving for humankind's next leap forward. The series has been released in DVD format on 16 October 2012 and includes a 16-page viewer's guide. Episodes Episode 1 : Machines Episode 2 : Health Episode 3 : Technology Episode 4 : Environment Episode 5 : Biology See also *''Into the Universe with Stephen Hawking'' *''Stephen Hawking's Universe'' References External links * * 2011 British television series debuts 2011 British television series endings 2010s British documentary television series Channel 4 documentary series 2010s British television miniseries British English-language television shows British documentary television series about science {{sci-documentary-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roger Penrose
Sir Roger Penrose (born 8 August 1931) is an English mathematician, mathematical physicist, Philosophy of science, philosopher of science and Nobel Prize in Physics, Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics in the University of Oxford, an emeritus fellow of Wadham College, Oxford, and an honorary fellow of St John's College, Cambridge, and University College London. Penrose has contributed to the mathematical physics of general relativity and physical cosmology, cosmology. He has received several prizes and awards, including the 1988 Wolf Prize in Physics, which he shared with Stephen Hawking for the Penrose–Hawking singularity theorems, and the 2020 Nobel Prize in Physics "for the discovery that black hole formation is a robust prediction of the general theory of relativity". He won the Royal Society Prizes for Science Books, Royal Society Science Books Prize for ''The Emperor's New Mind'' (1989), which outlines his views on physics and con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacetime Singularity
A gravitational singularity, spacetime singularity, or simply singularity, is a theoretical condition in which gravity is predicted to be so intense that spacetime itself would break down catastrophically. As such, a singularity is by definition no longer part of the regular spacetime and cannot be determined by "where" or "when”. Gravitational singularities exist at a junction between general relativity and quantum mechanics; therefore, the properties of the singularity cannot be described without an established theory of quantum gravity. Trying to find a complete and precise definition of singularities in the theory of general relativity, the current best theory of gravity, remains a difficult problem. A singularity in general relativity can be defined by the scalar invariant curvature becoming infinite or, better, by a geodesic being incomplete. General relativity predicts that any object collapsing beyond its Schwarzschild radius would form a black hole, inside which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penrose–Hawking Singularity Theorems
The Penrose–Hawking singularity theorems (after Roger Penrose and Stephen Hawking) are a set of results in general relativity that attempt to answer the question of when gravitation produces singularities. The Penrose singularity theorem is a theorem in semi-Riemannian geometry and its general relativistic interpretation predicts a gravitational singularity in black hole formation. The Hawking singularity theorem is based on the Penrose theorem and it is interpreted as a gravitational singularity in the Big Bang situation. Penrose shared half of the Nobel Prize in Physics in 2020 "for the discovery that black hole formation is a robust prediction of the general theory of relativity". Singularity A singularity in solutions of the Einstein field equations is one of three things: * Spacelike singularities: The singularity lies in the future or past of all events within a certain region. The Big Bang singularity and the typical singularity inside a non-rotating, uncharge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawking Radiation
Hawking radiation is black-body radiation released outside a black hole's event horizon due to quantum effects according to a model developed by Stephen Hawking in 1974. The radiation was not predicted by previous models which assumed that once electromagnetic radiation is inside the event horizon, it cannot escape. Hawking radiation is predicted to be extremely faint and is many orders of magnitude below the current best telescopes' detecting ability. Hawking radiation would reduce the mass and rotational energy of black holes and consequently cause black hole evaporation. Because of this, black holes that do not gain mass through other means are expected to shrink and ultimately vanish. For all except the smallest black holes, this happens extremely slowly. The radiation temperature, called Hawking temperature, is inversely proportional to the black hole's mass, so micro black holes are predicted to be larger emitters of radiation than larger black holes and should dissipat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conformal Cyclic Cosmology
Conformal cyclic cosmology (CCC) is a cosmological model in the framework of general relativity and proposed by the theoretical physicist Roger Penrose. In CCC, the universe iterates through infinite cycles, with the future timelike infinity (i.e. the latest end of any possible timescale evaluated for any point in space) of each previous iteration being identified with the Big Bang singularity of the next. Penrose popularized this theory in his 2010 book ''Cycles of Time: An Extraordinary New View of the Universe''. Basic construction Penrose's basic construction is to connect a countable sequence of open Friedmann–Lemaître–Robertson–Walker metric (FLRW) spacetimes, each representing a Big Bang followed by an infinite future expansion. Penrose noticed that the past conformal boundary of one copy of FLRW spacetime can be "attached" to the future conformal boundary of another, after an appropriate conformal rescaling. In particular, each individual FLRW metric g_ is mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawking Point
Conformal cyclic cosmology (CCC) is a cosmological model in the framework of general relativity and proposed by the theoretical physicist Roger Penrose. In CCC, the universe iterates through infinite cycles, with the future timelike infinity (i.e. the latest end of any possible timescale evaluated for any point in space) of each previous iteration being identified with the Big Bang singularity of the next. Penrose popularized this theory in his 2010 book ''Cycles of Time: An Extraordinary New View of the Universe''. Basic construction Penrose's basic construction is to connect a countable sequence of open Friedmann–Lemaître–Robertson–Walker metric (FLRW) spacetimes, each representing a Big Bang followed by an infinite future expansion. Penrose noticed that the past conformal boundary of one copy of FLRW spacetime can be "attached" to the future conformal boundary of another, after an appropriate conformal rescaling. In particular, each individual FLRW metric g_ is multi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Don Page (physicist)
Don Nelson Page (born December 31, 1948) is an American-born Canadian theoretical physicist at the University of Alberta, Canada. Work Page's work focuses on quantum cosmology and theoretical gravitational physics, and he is noted for being a doctoral student of Stephen Hawking, who was at Caltech during 1974-1975, in addition to publishing several journal articles with him. Page got his BA at William Jewell College in the United States in 1971, attaining an MS in 1972 and a PhD in 1976 at Caltech. His professional career started as a research assistant in Cambridge from 1976-1979, followed by an assistant professorship at Penn State from 1979-1983, and then an associate professor at Penn State until 1986 before taking on the title of professor in 1986. Page spent four more years at Penn State before moving to become a professor at the University of Alberta in Canada in 1990. In 1993, he argued that if a black hole starts in a pure quantum state and evaporates completely by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AdS Black Hole
In theoretical physics, an anti-de Sitter (AdS) black hole is a black hole solution of general relativity or its extensions which represents an isolated massive object, but with a negative cosmological constant. Such a solution asymptotically approaches anti-de Sitter space at spatial infinity, and is a generalization of the Kerr vacuum solution, which asymptotically approaches Minkowski spacetime at spatial infinity. In 3+1 dimensions, the metric is given by ds^2 = - \left( k^2r^2 + 1 - \frac \right)dt^2 + \fracdr^2 + r^2 d\Omega^2 where is the time coordinate, is the radial coordinate, are the polar coordinates, is a constant and is the AdS curvature. In general, in dimensions, the metric is given by ds^2 = - \left( k^2r^2 + 1 - \frac \right)dt^2 + \fracdr^2 + r^2 d\Omega^2 According to the AdS/CFT correspondence, if gravity were quantized, an AdS black hole would be dual to a thermal state on the conformal boundary. In the context of say, AdS/QCD, this would correspon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
