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Karl Schwarzschild
Karl Schwarzschild (; 9 October 1873 – 11 May 1916) was a German physicist and astronomer. Schwarzschild provided the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished in 1915, the same year that Einstein first introduced general relativity. The Schwarzschild solution, which makes use of Schwarzschild coordinates and the Schwarzschild metric, leads to a derivation of the Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole. Schwarzschild accomplished this while serving in the German army during World War I. He died the following year, possibly from the autoimmune disease pemphigus, which he developed while at the Russian front. Asteroid 837 Schwarzschilda is named in his honour, as is the large crater ''Schwarzschild'', on the far side of the Moon. Life Karl Schwarzschild was born on 9 October 1873 in Frankfurt on Main, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frankfurt Am Main
Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the foreland of the Taunus on its namesake Main (river), Main, it forms a continuous conurbation with Offenbach am Main; Frankfurt Rhein-Main Regional Authority, its urban area has a population of over 2.7 million. The city is the heart of the larger Rhine-Main metropolitan region, which has a population of more than 5.8 million and is Germany's Metropolitan regions in Germany, second-largest metropolitan region after the Rhine-Ruhr metropolitan region, Rhine-Ruhr region and the List of EU metropolitan regions by GDP#2021 ranking of top four German metropolitan regions, fourth largest metropolitan region by GDP in the European Union (EU). Frankfurt is one of the ''de facto'' four main capitals of the European Union (alongside Brussels, Luxembourg Cit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagrangian (field Theory)
Lagrangian field theory is a formalism in classical field theory. It is the field-theoretic analogue of Lagrangian mechanics. Lagrangian mechanics is used to analyze the motion of a system of discrete particles each with a finite number of degrees of freedom. Lagrangian field theory applies to continua and fields, which have an infinite number of degrees of freedom. One motivation for the development of the Lagrangian formalism on fields, and more generally, for classical field theory, is to provide a clear mathematical foundation for quantum field theory, which is infamously beset by formal difficulties that make it unacceptable as a mathematical theory. The Lagrangians presented here are identical to their quantum equivalents, but, in treating the fields as classical fields, instead of being quantized, one can provide definitions and obtain solutions with properties compatible with the conventional formal approach to the mathematics of partial differential equations. This enabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schwarzschild (crater)
Schwarzschild is a large Lunar craters, lunar impact crater, approximately in diameter. It is located in the northern part of the Moon's Far side (Moon), far side. The nearest craters of note are Seares (crater), Seares to the northeast, and Gamow (crater), Gamow to the southeast. It was named after German physicist and astronomer Karl Schwarzschild (1873–1916). The somewhat irregular outer rim of Schwarzschild has been overlain by many smaller impact craters, including most notably Schwarzschild K across the southeastern face and Schwarzschild D on the northeastern rim. The rim is roughly circular in form, with an outward bulge along the southwestern side. The rim has been softened and modified by impact erosion, particularly to the northeast. Just to the northeast of Schwarzschild K is a short chain of small craters lying across the rim and inner wall of Schwarzschild. The inner floor of Schwarzschild is relatively level by comparison with the rugged terrain outside, and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
837 Schwarzschilda
837 Schwarzschilda, provisional designation 1916 AG, is a low-eccentric, well-observed asteroid from the asteroid belt, orbiting the Sun with a period of 3.48 years at a distance of 2.21–2.39 AU. It was discovered by German astronomer Max Wolf at Heidelberg Observatory on 23 September 1916. The main-belt asteroid was named after physicist and astronomer Karl Schwarzschild (1873–1916), who had died earlier that year. He was director of the observatories in Göttingen and Potsdam, known for his work in photometry, geometrical optics, stellar statistics and theoretical astrophysics, most notably for producing the first exact solutions to Einstein's field equations. At the time, it was custom to give feminized names to minor planets. See also * Meanings of minor planet names: 501–1000 * Schwarzschild radius The Schwarzschild radius is a parameter in the Schwarzschild solution to Einstein's field equations that corresponds to the radius of a sphere in flat space that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Front (World War I)
The Eastern Front or Eastern Theater, of World War I, was a theater (warfare), theater of operations that encompassed at its greatest extent the entire frontier between Russian Empire, Russia and Kingdom of Romania, Romania on one side and Austria-Hungary, Kingdom of Bulgaria, Bulgaria, the Ottoman Empire, and German Empire, Germany on the other. It ranged from the Baltic Sea in the north to the Black Sea in the south, involved most of Eastern Europe, and stretched deep into Central Europe. The term contrasts with the Western Front (World War I), Western Front, which was being fought in Belgium and French Third Republic, France. Unlike the static warfare on the Western Front, the fighting on the geographically larger Eastern Front was maneuver warfare, more dynamic, often involving the flanking and encirclement of entire formations, and resulted in over 100,000 square miles of territory becoming occupied by a foreign power. At the start of the war Russia launched offensives agai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pemphigus
Pemphigus ( or ) is a rare group of blistering autoimmune diseases that affect the skin and mucous membranes. The name is derived from the Greek root ''pemphix'', meaning "blister". In pemphigus, autoantibody, autoantibodies form against desmoglein, which forms the "glue" that attaches adjacent Epidermis (skin), epidermal cells via attachment points called desmosomes. When autoantibodies attack desmogleins, the cells become separated from each other and the epidermis becomes detached, a phenomenon called acantholysis. This causes blisters that slough off and turn into Ulcer (dermatology), sores. In some cases, these blisters can cover a large area of the skin. Originally, the cause of this disease was unknown, and "pemphigus" was used to refer to any blistering disease of the skin and mucosa. In 1964, researchers found that the blood of patients with pemphigus contained antibodies to the layers of skin that separate to form the blisters. In 1971, an article investigating th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoimmunity
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an " autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, Henoch–Schönlein purpura, systemic lupus erythematosus, Sjögren syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis, ankylosing spondylitis, polymyositis, dermatomyositis, and multiple sclerosis. Autoimmune diseases are very often treated with steroids. Autoimmunity means presence of antibodies or T cells that react with self-protein and is present in all individuals, even in normal health state. It causes autoimmune diseases if self-reactivity can lead to tissue damage. History In the later 19th century, it was believed that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting took place mainly in European theatre of World War I, Europe and the Middle Eastern theatre of World War I, Middle East, as well as in parts of African theatre of World War I, Africa and the Asian and Pacific theatre of World War I, Asia-Pacific, and in Europe was characterised by trench warfare; the widespread use of Artillery of World War I, artillery, machine guns, and Chemical weapons in World War I, chemical weapons (gas); and the introductions of Tanks in World War I, tanks and Aviation in World War I, aircraft. World War I was one of the List of wars by death toll, deadliest conflicts in history, resulting in an estimated World War I casualties, 10 million military dead and more than 20 million wounded, plus some 10 million civilian de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hole
A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. The boundary (topology), boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but 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. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with thermal radiation, the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the Orders of magnitude (temperature), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Event Horizon
In astrophysics, an event horizon is a boundary beyond which events cannot affect an outside observer. Wolfgang Rindler coined the term in the 1950s. In 1784, John Michell proposed that gravity can be strong enough in the vicinity of massive compact objects that even light cannot escape. At that time, the Newtonian theory of gravitation and the so-called corpuscular theory of light were dominant. In these theories, if the escape velocity of the gravitational influence of a massive object exceeds the speed of light, then light originating inside or from it can escape temporarily but will return. In 1958, David Finkelstein used general relativity to introduce a stricter definition of a local black hole event horizon as a boundary beyond which events of any kind cannot affect an outside observer, leading to information and firewall paradoxes, encouraging the re-examination of the concept of local event horizons and the notion of black holes. Several theories were subsequently d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schwarzschild Solution
In Einstein's theory of general relativity, the Schwarzschild metric (also known as the Schwarzschild solution) is an exact solution to the Einstein field equations that describes the gravitational field outside a spherical mass, on the assumption that the electric charge of the mass, angular momentum of the mass, and universal cosmological constant are all zero. The solution is a useful approximation for describing slowly rotating astronomical objects such as many stars and planets, including Earth and the Sun. It was found by Karl Schwarzschild in 1916. According to Birkhoff's theorem, the Schwarzschild metric is the most general spherically symmetric vacuum solution of the Einstein field equations. A Schwarzschild black hole or static black hole is a black hole that has neither electric charge nor angular momentum (non-rotating). A Schwarzschild black hole is described by the Schwarzschild metric, and cannot be distinguished from any other Schwarzschild black hole except by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General theory of relativity, 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 in physics, time, or four-dimensional spacetime. In particular, the ''curvature of spacetime'' is directly related to the energy and momentum of whatever is present, including matter and radiation. 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 gravity in classical mechanics, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
