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Timeline Of Black Hole Physics
Timeline of black hole physics Pre-20th century * 1640 — Ismaël Bullialdus suggests an inverse-square gravitational force law * 1676 — Ole Rømer demonstrates that light has a finite speed * 1684 — Isaac Newton writes down his inverse-square law of universal gravitation * 1758 — Rudjer Josip Boscovich develops his theory of forces, where gravity can be repulsive on small distances. This implied that strange classical bodies that would not allow other bodies to reach their surfaces, such as what we know call white holes, could exist. * 1784 — John Michell discusses classical bodies which have escape velocities greater than the speed of light * 1795 — Pierre Laplace discusses classical bodies which have escape velocities greater than the speed of light * 1798 — Henry Cavendish measures the gravitational constant ''G'' * 1876 — William Kingdon Clifford suggests that the motion of matter may be due to changes in the geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline
A timeline is a list of events displayed in chronological order. It is typically a graphic design showing a long bar labelled with dates paralleling it, and usually contemporaneous events. Timelines can use any suitable scale representing time, suiting the subject and data; many use a linear scale, in which a unit of distance is equal to a set amount of time. This timescale is dependent on the events in the timeline. A timeline of evolution can be over millions of years, whereas a timeline for the day of the September 11 attacks can take place over minutes, and that of an explosion over milliseconds. While many timelines use a linear timescale—especially where very large or small timespans are relevant -- logarithmic timelines entail a logarithmic scale of time; some "hurry up and wait" chronologies are depicted with zoom lens metaphors. More usually, "timeline" refers merely to a data set which could be displayed as described above. For example, this meaning is used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Cavendish
Henry Cavendish ( ; 10 October 1731 – 24 February 1810) was an English experimental and theoretical chemist and physicist. He is noted for his discovery of hydrogen, which he termed "inflammable air". He described the density of inflammable air, which formed water on combustion, in a 1766 paper, ''On Factitious Airs''. Antoine Lavoisier later reproduced Cavendish's experiment and gave the element its name. A shy man, Cavendish was distinguished for great accuracy and precision in his researches into the composition of atmospheric air, the properties of different gases, the synthesis of water, the law governing electrical attraction and repulsion, a mechanical theory of heat, and calculations of the density (and hence the mass) of the Earth. His experiment to measure the density of the Earth (which, in turn, allows the gravitational constant to be calculated) has come to be known as the Cavendish experiment. Early life Henry Cavendish was born on 10 October 1731 in Nice, whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Weyl
Hermann Klaus Hugo Weyl (; ; 9 November 1885 – 8 December 1955) was a German mathematician, theoretical physicist, logician and philosopher. Although much of his working life was spent in Zürich, Switzerland, and then Princeton, New Jersey, he is associated with the University of Göttingen tradition of mathematics, represented by Carl Friedrich Gauss, David Hilbert and Hermann Minkowski. His research has had major significance for theoretical physics as well as purely mathematical disciplines such as number theory. He was one of the most influential mathematicians of the twentieth century, and an important member of the Institute for Advanced Study during its early years. Weyl contributed to an exceptionally wide range of fields, including works on space, time, matter, philosophy, logic, symmetry and the history of mathematics. He was one of the first to conceive of combining general relativity with the laws of electromagnetism. Freeman Dyson wrote that Weyl alone bore comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reissner–Nordström Metric
In physics and astronomy, the Reissner–Nordström metric is a Static spacetime, static solution to the Einstein–Maxwell equations, Einstein–Maxwell field equations, which corresponds to the gravitational field of a charged, non-rotating, spherically symmetric body of mass ''M''. The analogous solution for a charged, rotating body is given by the Kerr–Newman metric. The metric was discovered between 1916 and 1921 by Hans Reissner, Hermann Weyl, Gunnar Nordström and George Barker Jeffery independently. Metric In spherical coordinates , the Reissner–Nordström metric (i.e. the line element) is : ds^2 = c^2\, d\tau^2 = \left( 1 - \frac + \frac \right) c^2\, dt^2 -\left( 1 - \frac + \frac \right)^ \, dr^2 - ~ r^2 \, d\theta^2 - ~ r^2\sin^2\theta \, d\varphi^2 , where * c is the speed of light * \tau is the proper time * t is the time coordinate (measured by a stationary clock at infinity). * r is the radial coordinate * (\theta, \varphi) are the spherical angles * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunnar Nordström
Gunnar Nordström (12 March 1881 – 24 December 1923) was a Finland, Finnish theoretical physicist best remembered for Nordström's theory of gravitation, his theory of gravitation, which was an early competitor of general relativity. Nordström is often designated by modern writers as ''The Einstein of Finland'' due to his novel work in similar fields with similar methods to Einstein.Raimo Keskinen (1981): Gunnar Nordström 1881B1923. Arkhimedes 2/1981, s. 71B84. In Finnish, excerpt http://www.tieteessatapahtuu.fi/797/KESKINEN.pdf Education and career Nordström graduated high-school from ''Brobergska skolan'' in central Helsinki 1899. At first he went on to study mechanical engineering, graduating in 1903 from the Helsinki University of Technology, Polytechnic institute in Helsinki, later renamed Helsinki University of Technology and today a part of the Aalto University. During his studies he developed an interest for more theoretical subjects, proceeding after graduation to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Reissner
Hans Jacob Reissner, also known as Jacob Johannes Reissner (18 January 1874, Berlin – 2 October 1967, Mt. Angel, Oregon), was a German aeronautical engineer whose avocation was mathematical physics. During World War I he was awarded the Iron Cross second class (for civilians) for his pioneering work on aircraft design. Biography Reissner was born into a wealthy Berlin family that benefited from an inheritance from his great-uncle on his mother's side. As a young engineering graduate, he spent a year in the U.S. working as a draftsman. After this year, he broadened his academic interests to include physics. As a young academic, he published mathematical papers on engineering problems. Before World War I, Reissner designed the first successful all-metal aircraft, the Reissner Canard (or Ente) with both skin and structure made of metal. This was constructed with assistance from Hugo Junkers who had previously shown little interest in aviation. Both were professors at the Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass
Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particle, elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple Mass in special relativity, definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure (mathematics), measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the Force, strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is Mass versus weight, not the same as weight, even though mass is often determined by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometry
Geometry (; ) is a branch of mathematics concerned with properties of space such as the distance, shape, size, and relative position of figures. Geometry is, along with arithmetic, one of the oldest branches of mathematics. A mathematician who works in the field of geometry is called a ''List of geometers, geometer''. Until the 19th century, geometry was almost exclusively devoted to Euclidean geometry, which includes the notions of point (geometry), point, line (geometry), line, plane (geometry), plane, distance, angle, surface (mathematics), surface, and curve, as fundamental concepts. Originally developed to model the physical world, geometry has applications in almost all sciences, and also in art, architecture, and other activities that are related to graphics. Geometry also has applications in areas of mathematics that are apparently unrelated. For example, methods of algebraic geometry are fundamental in Wiles's proof of Fermat's Last Theorem, Wiles's proof of Fermat's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space
Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as '' spacetime''. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. In the 19th and 20th centuries mathematicians began to examine geometries that are non-Euclidean, in which space is conceived as '' curved'', rather than '' flat'', as in the Euclidean space. According to Albert Einstein's theory of general relativity, space around gravitational fields deviates from Euclidean space. Experimental tests of general relativity have confirmed that non-Euclidean geometries provide a bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric Tensor
In the mathematical field of differential geometry, a metric tensor (or simply metric) is an additional structure on a manifold (such as a surface) that allows defining distances and angles, just as the inner product on a Euclidean space allows defining distances and angles there. More precisely, a metric tensor at a point of is a bilinear form defined on the tangent space at (that is, a bilinear function that maps pairs of tangent vectors to real numbers), and a metric field on consists of a metric tensor at each point of that varies smoothly with . A metric tensor is ''positive-definite'' if for every nonzero vector . A manifold equipped with a positive-definite metric tensor is known as a Riemannian manifold. Such a metric tensor can be thought of as specifying ''infinitesimal'' distance on the manifold. On a Riemannian manifold , the length of a smooth curve between two points and can be defined by integration, and the distance between and can be defined as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marcel Grossmann
Marcel Grossmann (; April 9, 1878 – September 7, 1936) was a Swiss mathematician who was a friend and classmate of Albert Einstein. Grossmann came from an old Swiss family in Zürich. His father managed a textile factory. He became a Professor of Mathematics at the Federal Polytechnic School in Zürich, today the ETH Zurich, specializing in descriptive geometry. Career In 1900 Grossmann graduated from the Federal Polytechnic School (ETH) and became an assistant to the geometer Wilhelm Fiedler. He continued to do research on non-Euclidean geometry and taught in high schools for the next seven years. In 1902, he earned his doctorate from the University of Zurich with the thesis ''Ueber die metrischen Eigenschaften kollinearer Gebilde'' (translated ''On the Metrical Properties of Collinear Structures'') with Fiedler as advisor. In 1907, he was appointed full professor of descriptive geometry at the Federal Polytechnic School. As a professor of geometry, Grossmann organized summe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
