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Hans Adolf Buchdahl
Hans Adolf Buchdahl (7 July 1919 – 7 January 2010) was a German-born Australian physicist. He contributed to general relativity, thermodynamics and optics. He is particularly known for developing f(R) gravity and Buchdahl's theorem on the Schwarzschild's solution for the inside of a spherical star. Biography Hans Adolf Buchdahl was born in Mainz, Germany, in a Jewish family (he used the spelling Adolph to dissociate himself from Hitler). His older brother Gerd Buchdahl was a well-known philosopher in science. In 1933, Gerd took Hans with him to England, to escape the Nazi government. At London, he completed a BSc and received the Associate of the Royal College of Science (ARCS) from Imperial College. When World War II began, the UK government, unable to determine individual allegiance, interned German nationals including many Jewish refugees already fully assimilated. In July 1940, Hans came to Australia together with Gerd on board the HMT Dunera. He was detained initiall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainz
Mainz () is the capital and largest city of Rhineland-Palatinate, Germany. Mainz is on the left bank of the Rhine, opposite to the place that the Main (river), Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-west, with Mainz on the left bank, and Wiesbaden, the capital of the neighbouring state Hesse, on the right bank. Mainz is an independent city with a population of 218,578 (as of 2019) and forms part of the Frankfurt Rhine-Main, Frankfurt Rhine-Main Metropolitan Region. Mainz was founded by the Roman Empire, Romans in the 1st century BC as a military fortress on the northernmost frontier of the empire and provincial capital of Germania Superior. Mainz became an important city in the 8th century AD as part of the Holy Roman Empire, capital of the Electorate of Mainz and seat of the Elector of Mainz, Archbishop-Elector of Mainz, the Primate (bishop), Primate of Germany. Mainz is famous as the birthplace of Johannes Gutenberg, the inventor of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting original research in relevant fields. Despite the name, the journal is no longer monthly, nor does it carry the notices of the Royal Astronomical Society. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second volume, after the Astronomical Society of London became the Royal Astronomical Society (RAS). Until 1960 it carried the monthly notices of the RAS, at which time these were transferred to the newly established ''Quarterly Journal of the Royal Astronomical Society'' (1960–1996) and then to its successor journal ''Astronomy & Geophysics'' (since 1997). Until 1965, MNRAS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics. Relativity and quantum mechanics are the two pillars of modern physics. His mass–energy equivalence formula , which arises from relativity theory, has been dubbed "the world's most famous equation". His work is also known for its influence on the philosophy of science. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory. His intellectual achievements and originality resulted in "Einstein" becoming synonymous with "genius". In 1905, a year sometimes described as his ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Einstein Field 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinor
In geometry and physics, spinors are elements of a complex vector space that can be associated with Euclidean space. Like geometric vectors and more general tensors, spinors transform linearly when the Euclidean space is subjected to a slight (infinitesimal) rotation. Unlike vectors and tensors, a spinor transforms to its negative when the space is continuously rotated through a complete turn from 0° to 360° (see picture). This property characterizes spinors: spinors can be viewed as the "square roots" of vectors (although this is inaccurate and may be misleading; they are better viewed as "square roots" of sections of vector bundles – in the case of the exterior algebra bundle of the cotangent bundle, they thus become "square roots" of differential forms). It is also possible to associate a substantially similar notion of spinor to Minkowski space, in which case the Lorentz transformations of special relativity play the role of rotations. Spinors were introduced in geome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tensor
In mathematics, a tensor is an algebraic object that describes a multilinear relationship between sets of algebraic objects related to a vector space. Tensors may map between different objects such as vectors, scalars, and even other tensors. There are many types of tensors, including scalars and vectors (which are the simplest tensors), dual vectors, multilinear maps between vector spaces, and even some operations such as the dot product. Tensors are defined independent of any basis, although they are often referred to by their components in a basis related to a particular coordinate system. Tensors have become important in physics because they provide a concise mathematical framework for formulating and solving physics problems in areas such as mechanics (stress, elasticity, fluid mechanics, moment of inertia, ...), electrodynamics (electromagnetic tensor, Maxwell tensor, permittivity, magnetic susceptibility, ...), general relativity ( stress–energy tensor, cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constantin Carathéodory
Constantin Carathéodory ( el, Κωνσταντίνος Καραθεοδωρή, Konstantinos Karatheodori; 13 September 1873 – 2 February 1950) was a Greek mathematician who spent most of his professional career in Germany. He made significant contributions to real and complex analysis, the calculus of variations, and measure theory. He also created an axiomatic formulation of thermodynamics. Carathéodory is considered one of the greatest mathematicians of his era and the most renowned Greek mathematician since antiquity. Origins Constantin Carathéodory was born in 1873 in Berlin to Greek parents and grew up in Brussels. His father Stephanos, a lawyer, served as the Ottoman ambassador to Belgium, St. Petersburg and Berlin. His mother, Despina, née Petrokokkinos, was from the island of Chios. The Carathéodory family, originally from Bosnochori or Vyssa, was well established and respected in Constantinople, and its members held many important governmental positions. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Aberration
In optics, aberration is a property of optical systems, such as lenses, that causes light to be spread out over some region of space rather than focused to a point. Aberrations cause the image formed by a lens to be blurred or distorted, with the nature of the distortion depending on the type of aberration. Aberration can be defined as a departure of the performance of an optical system from the predictions of paraxial optics. In an imaging system, it occurs when light from one point of an object does not converge into (or does not diverge from) a single point after transmission through the system. Aberrations occur because the simple paraxial theory is not a completely accurate model of the effect of an optical system on light, rather than due to flaws in the optical elements. An image-forming optical system with aberration will produce an image which is not sharp. Makers of optical instruments need to correct optical systems to compensate for aberration. Aberration can be anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canberra
Canberra ( ) is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The city is located at the northern end of the Australian Capital Territory at the northern tip of the Australian Alps, the country's highest mountain range. As of June 2021, Canberra's estimated population was 453,558. The area chosen for the capital had been inhabited by Indigenous Australians for up to 21,000 years, with the principal group being the Ngunnawal people. European settlement commenced in the first half of the 19th century, as evidenced by surviving landmarks such as St John's Anglican Church and Blundells Cottage. On 1 January 1901, federation of the colonies of Australia was achieved. Following a long dispute over whether Sydney or Melbourne should be the national capital, a compromise was reached: the new capital would be buil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hobart
Hobart ( ; Nuennonne/Palawa kani: ''nipaluna'') is the capital and most populous city of the Australian island state of Tasmania. Home to almost half of all Tasmanians, it is the least-populated Australian state capital city, and second-smallest if territories are taken into account, before Darwin, Northern Territory. Hobart is located in Tasmania's south-east on the estuary of the River Derwent, making it the most southern of Australia's capital cities. Its skyline is dominated by the kunanyi/Mount Wellington, and its harbour forms the second-deepest natural port in the world, with much of the city's waterfront consisting of reclaimed land. The metropolitan area is often referred to as Greater Hobart, to differentiate it from the City of Hobart, one of the five local government areas that cover the city. It has a mild maritime climate. The city lies on country which was known by the local Mouheneener people as nipaluna, a name which includes surrounding features such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HMT Dunera
HMT (Hired Military Transport) ''Dunera'' was a British passenger ship which, in 1940, became involved in a controversial transportation of thousands of "enemy aliens" to Australia. The British India Steam Navigation Company had operated a previous , which served as a troopship during the Second Boer War. Early service as a troopship After trials in 1937, she was handed over to the British-India Steam Navigation Company and served as a passenger liner and an educational cruise ship before seeing extensive service as a troopship throughout the Second World War. She was taken over by the Royal Navy as a troopship before hostilities started, and was taking troops to the Far East when her crew heard the news of war at Malta on 3 September 1939 (from private diary of telegraphist R H Wood). ''Dunera'' carried New Zealand troops to Egypt in January 1940. Transport voyage to Australia Background After Britain declared war on Germany the government set up aliens tribunals to distingu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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