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Anders Johan Lexell
Anders Johan Lexell (24 December 1740 – ) was a Finnish-Swedish astronomer, mathematician, and physicist who spent most of his life in Imperial Russia, where he was known as Andrei Ivanovich Leksel (Андрей Иванович Лексель). Lexell made important discoveries in polygonometry and celestial mechanics; the latter led to a comet named in his honour. La Grande Encyclopédie states that he was the prominent mathematician of his time who contributed to spherical trigonometry with new and interesting solutions, which he took as a basis for his research of comet and planet motion. His name was given to a theorem of spherical triangles. Lexell was one of the most prolific members of the Russian Academy of Sciences at that time, having published 66 papers in 16 years of his work there. A statement attributed to Leonhard Euler expresses high approval of Lexell's works: "Besides Lexell, such a paper could only be written by D'Alambert or me". Daniel Bernoulli als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Friedrich Anthing
Johann Friedrich Anthing (1753–1805) was a German serviceman, artist and historian. Biography Johann Friedrich Anthing was born on 26 May 1753 in Gotha (then in the Saxe-Coburg Duchy, now in Thuringia). After his theological studies in Iena, Anthing travelled across Europe, going from one royal court to the next, as a silhouette artist. He drew portraits of princes, courtiers and famous personalities such as Goethe during his stay at the Weimar court (1789). He was employed in Saint-Petersburg from 1783 and drew portraits of members of the imperial family, including Grand Duke Paul Petrovitch (then Paul I of Russia) and his wife Maria Fedorovna, as well as members of the Saint Petersburg Academy of Sciences. Anthing travelled to Frankfurt in 1790 to attend the crowning of Leopold II, and he published a description of the ceremony. In 1793, Anthing returned to Russia and became Marshal Alexander Suvorov's Aide-de-camp. He would later write a three-volume biography of Suvo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygonometry
Ordinary trigonometry studies triangles in the Euclidean plane . There are a number of ways of defining the ordinary Euclidean geometric trigonometric functions on real numbers, for example right-angled triangle definitions, unit circle definitions, series definitions, definitions via differential equations, and definitions using functional equations. Generalizations of trigonometric functions are often developed by starting with one of the above methods and adapting it to a situation other than the real numbers of Euclidean geometry. Generally, trigonometry can be the study of triples of points in any kind of geometry or space. A triangle is the polygon with the smallest number of vertices, so one direction to generalize is to study higher-dimensional analogs of angles and polygons: solid angles and polytopes such as tetrahedrons and -simplices. Trigonometry *In spherical trigonometry, triangles on the surface of a sphere are studied. The spherical triangle identities are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Academy Of Turku
The Royal Academy of Turku or the Royal Academy of Åbo ( sv, Kungliga Akademin i Åbo or ; la, Regia Academia Aboensis; fi, Turun akatemia) was the first university in Finland, and the only Finnish university that was founded when the country still was a part of Sweden. It was founded in 1640. In 1809, after Finland became a Grand Duchy under the suzerainty of the Russian czar, it was renamed the ''Imperial Academy of Turku''. In 1828, after the Great Fire of Turku, the institution was moved to Helsinki, in line with the relocation of the Grand Duchy's capital. It was finally renamed the University of Helsinki when Finland became a sovereign nation-state in 1917. History The academy was founded on 26 March 1640 by Queen Christina of Sweden at the proposal of Count Per Brahe, on base of Åbo Cathedral School (founded 1276). It was the third university in the Swedish Empire, following Uppsala University (founded 1477) and the Academia Gustaviana (now the University of Tartu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lexell (crater)
Lexell is a lunar impact crater that lies across the southeastern rim of the huge walled plain Deslandres, in the southern part of the Moon. It was named after Swedish-Russian mathematician and astronomer Anders Johan Lexell. To the northeast is the walled plain Walther, and to the south is Orontius, another walled plain. This is a somewhat irregular formation with a wide break in the northern rim. The western rim forms a low, arcing wall, and is overlain to the southwest by Lexell H after passing the rim of Deslandres. The rim peaks along the southeast, then comes to an end at a rugged promontory-like ridge. The interior floor has been resurfaced by lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ... to the northwest and in sections of the remainder of the floor. There are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2004 Lexell
2004 Lexell, provisional designation , is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 7.5 kilometers in diameter. The asteroid was discovered on 22 September 1973, by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula, and later named for Swedish-Russian astronomer and mathematician Anders Johan Lexell. Classification and orbit ''Lexell'' is a member of the Flora family, one of the largest collisional populations of stony asteroids. It orbits the Sun at a distance of 2.0–2.3 AU once every 3 years and 2 months (1,169 days). Its orbit has an eccentricity of 0.08 and an inclination of 2 ° with respect to the ecliptic. The asteroid was first identified as at the Finnish Turku Observatory in November 1938, extending the body's observation arc by 35 years prior to its official discovery observation at Nauchnij. Physical characteristics Pan-STARRS photometric survey ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chair (academic)
Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professors are usually experts in their field and teachers of the highest rank. In most systems of academic ranks, "professor" as an unqualified title refers only to the most senior academic position, sometimes informally known as "full professor". In some countries and institutions, the word "professor" is also used in titles of lower ranks such as associate professor and assistant professor; this is particularly the case in the United States, where the unqualified word is also used colloquially to refer to associate and assistant professors as well. This usage would be considered incorrect among other academic communities. However, the otherwise unqualified title "Professor" designated with a capital letter nearly always refers to a full professor. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Euler
Johann Albrecht Euler (27 November 1734 – 17 September 1800) was a Swiss-Russian astronomer and mathematician. Also known as ''Johann Albert Euler'' or ''John-Albert Euler'', he was the first child born to the great Swiss mathematician Leonhard Euler (1707–1783), who had emigrated or the first timeto Saint-Petersburg on 17 May 1727. His mother was Katharina Gsell (1707–1773) whose maternal grandmother was the famous scientific illustrator Maria Sibylla Merian (1647–1717) and whose father was the Swiss Baroque painter Georg Gsell (1673–1740) who had emigrated to Russia in 1716. Katharina married Leonhard Euler on 7 January 1734 and Johann Albert would be the eldest of their 13 children (only 5 of whom survived childhood). In 1754 he became a member of the Berlin Academy. In 1758, he served briefly as director of the Astronomical Calculation Institute (ARI). On Euler's return to St. Petersburg in 1765, he was appointed as the chair of physics at the St. Petersburg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel Bernoulli
Daniel Bernoulli FRS (; – 27 March 1782) was a Swiss mathematician and physicist and was one of the many prominent mathematicians in the Bernoulli family from Basel. He is particularly remembered for his applications of mathematics to mechanics, especially fluid mechanics, and for his pioneering work in probability and statistics. His name is commemorated in the Bernoulli's principle, a particular example of the conservation of energy, which describes the mathematics of the mechanism underlying the operation of two important technologies of the 20th century: the carburetor and the airplane wing. Early life Daniel Bernoulli was born in Groningen, in the Netherlands, into a family of distinguished mathematicians. Rothbard, MurrayDaniel Bernoulli and the Founding of Mathematical Economics ''Mises Institute'' (excerpted from ''An Austrian Perspective on the History of Economic Thought'') The Bernoulli family came originally from Antwerp, at that time in the Spanish Netherlands, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D'Alambert
Jean-Baptiste le Rond d'Alembert (; ; 16 November 1717 – 29 October 1783) was a French mathematician, mechanician, physicist, philosopher, and music theorist. Until 1759 he was, together with Denis Diderot, a co-editor of the ''Encyclopédie''. D'Alembert's formula for obtaining solutions to the wave equation is named after him. The wave equation is sometimes referred to as d'Alembert's equation, and the fundamental theorem of algebra is named after d'Alembert in French. Early years Born in Paris, d'Alembert was the natural son of the writer Claudine Guérin de Tencin and the chevalier Louis-Camus Destouches, an artillery officer. Destouches was abroad at the time of d'Alembert's birth. Days after birth his mother left him on the steps of the church. According to custom, he was named after the patron saint of the church. D'Alembert was placed in an orphanage for foundling children, but his father found him and placed him with the wife of a glazier, Madame Rousseau, with who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spherical Triangles
Spherical trigonometry is the branch of spherical geometry that deals with the metrical relationships between the sides and angles of spherical triangles, traditionally expressed using trigonometric functions. On the sphere, geodesics are great circles. Spherical trigonometry is of great importance for calculations in astronomy, geodesy, and navigation. The origins of spherical trigonometry in Greek mathematics and the major developments in Islamic mathematics are discussed fully in History of trigonometry and Mathematics in medieval Islam. The subject came to fruition in Early Modern times with important developments by John Napier, Delambre and others, and attained an essentially complete form by the end of the nineteenth century with the publication of Todhunter's textbook ''Spherical trigonometry for the use of colleges and Schools''. Since then, significant developments have been the application of vector methods, quaternion methods, and the use of numerical methods. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Motion
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a more accurate calculation and understanding of the exact mechanics of orb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently bright, a comet may be seen from Earth without the aid of a telescope and may subtend an arc of 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures and religions. Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several mill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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