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Alexander Aleksandrovich Friedmann
Alexander Alexandrovich Friedmann (also spelled Friedman or Fridman ; russian: Алекса́ндр Алекса́ндрович Фри́дман) (June 16 .S. 4 1888 – September 16, 1925) was a Russian and Soviet physicist and mathematician. He is best known for his pioneering theory that the universe was expanding, governed by a set of equations he developed now known as the Friedmann equations. Early life Alexander Friedmann was born to the composer and ballet dancer Alexander Friedmann (who was a son of a baptized Jewish cantonist) and the pianist Ludmila Ignatievna Voyachek (who was a daughter of the Czech composer Hynek Vojáček). Friedmann was baptized into the Russian Orthodox Church as an infant, and lived much of his life in Saint Petersburg. Friedmann obtained his degree from St. Petersburg State University in 1910, and became a lecturer at Saint Petersburg Mining Institute. From his school days, Friedmann found a lifelong companion in Jacob Tamarkin, who wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Petersburg
Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), is the second-largest city in Russia. It is situated on the Neva River, at the head of the Gulf of Finland on the Baltic Sea, with a population of roughly 5.4 million residents. Saint Petersburg is the fourth-most populous city in Europe after Istanbul, Moscow and London, the most populous city on the Baltic Sea, and the world's northernmost city of more than 1 million residents. As Russia's Imperial capital, and a historically strategic port, it is governed as a federal city. The city was founded by Tsar Peter the Great on 27 May 1703 on the site of a captured Swedish fortress, and was named after apostle Saint Peter. In Russia, Saint Petersburg is historically and culturally associated with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expanding Universe
The expansion of the universe is the increase in distance between any two given gravitationally unbound parts of the observable universe with time. It is an intrinsic expansion whereby the scale of space itself changes. The universe does not expand "into" anything and does not require space to exist "outside" it. This expansion involves neither space nor objects in space "moving" in a traditional sense, but rather it is the metric (which governs the size and geometry of spacetime itself) that changes in scale. As the spatial part of the universe's spacetime metric increases in scale, objects become more distant from one another at ever-increasing speeds. To any observer in the universe, it appears that all of space is expanding, and that all but the nearest galaxies (which are bound by gravity) recede at speeds that are proportional to their distance from the observer. While objects within space cannot travel faster than light, this limitation does not apply to the effects of ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Howard Percy Robertson
Howard Percy "Bob" Robertson (January 27, 1903 – August 26, 1961) was an American mathematician and physicist known for contributions related to physical cosmology and the uncertainty principle. He was Professor of Mathematical Physics at the California Institute of Technology and Princeton University. Robertson made important contributions to the mathematics of quantum mechanics, general relativity and differential geometry. Applying relativity to cosmology, he independently developed the concept of an expanding universe. His name is most often associated with the Poynting–Robertson effect, the process by which solar radiation causes a dust mote orbiting a star to lose angular momentum, which he also described in terms of general relativity. During World War II, Robertson served with the National Defense Research Committee (NDRC) and the Office of Scientific Research and Development (OSRD). He served as Technical Consultant to the Secretary of War, the OSRD Liaison Officer i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeitschrift Für Physik
''Zeitschrift für Physik'' (English: ''Journal for Physics'') is a defunct series of German peer-reviewed physics journals established in 1920 by Springer Berlin Heidelberg. The series stopped publication in 1997, when it merged with other journals to form the new ''European Physical Journal'' series. It had grown to four parts over the years. History *''Zeitschrift für Physik'' (1920–1975 ), The first three issues were published as a supplement to '' Verhandlungen der Deutschen Physikalischen Gesellschaft''. The journal split in parts A and B in 1975. :*''Zeitschrift für Physik A'' (1975–1997). The original subtitle was ''Atoms and Nuclei'' (). In 1986, it split in ''Zeitschrift für Physik A: Atomic Nuclei'' () and ''Zeitschrift für Physik D''. ''Zeitschrift für Physik A'' now continues as the ''European Physical Journal A''. :*''Zeitschrift für Physik B'' (1975–1997). This is the result of the split of ''Zeitschrift für Physik'' and the merger of ''Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Lemaître
Georges Henri Joseph Édouard Lemaître ( ; ; 17 July 1894 – 20 June 1966) was a Belgian Catholic priest, theoretical physicist, mathematician, astronomer, and professor of physics at the Catholic University of Louvain. He was the first to theorize that the recession of nearby galaxies can be explained by an expanding universe, which was observationally confirmed soon afterwards by Edwin Hubble. He first derived "Hubble's law", now called the Hubble–Lemaître law by the IAU, and published the first estimation of the Hubble constant in 1927, two years before Hubble's article. Lemaître also proposed the "Big Bang theory" of the origin of the universe, calling it the "hypothesis of the primeval atom", and later calling it "the beginning of the world". Early life After a classical education at a Jesuit secondary school, the Collège du Sacré-Coeur, in Charleroi, in Belgium, Lemaître began studying civil engineering at the Catholic University of Louvain at the age of 17. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belgians
Belgians ( nl, Belgen; french: Belges; german: Belgier) are people identified with the Kingdom of Belgium, a federal state in Western Europe. As Belgium is a multinational state, this connection may be residential, legal, historical, or cultural rather than ethnic. The majority of Belgians, however, belong to two distinct ethnic groups or ''communities'' ( nl, gemeenschap, links=no; french: communauté, links=no) native to the country, i.e. its historical regions: Flemings in Flanders, who speak Dutch; and Walloons in Wallonia, who speak French or Walloon. There is also a substantial Belgian diaspora, which has settled primarily in the United States, Canada, France, and the Netherlands. Etymology The 1830 revolution led to the establishment of an independent country under a provisional government and a national congress. The name "Belgium" was adopted for the country, the word being derived from ''Gallia Belgica'', a Roman province in the northernmost part of Gaul that, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Wilhelm Wirtz
Carl Wilhelm Wirtz (24 August 1876 in Krefeld – 18 February 1939 in Hamburg) was an astronomer who spent his time between the Kiel Observatory in Germany and the Observatory of Strasbourg, France. He is known for statistically showing the existence of a redshift-distance correlation for spiral galaxies. Scientific career As already Vesto Slipher in 1912, Wirtz in 1918 observed a systematic redshift of spiral nebulae, which was difficult to interpret in terms of a cosmological model in which the Universe is filled more or less uniformly with stars and nebulae. Wirtz additionally used the equivalent in German of ''K correction''. The term continues to be used in present-day observational cosmology, but Wirtz's observational evidence that the Universe is expanding is not often mentioned. He wrote: In 1922, he wrote a paper where he argued that the observational results suggest, that the redshifts of distant galaxies are becoming higher than more closer ones, which he interpre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hubble's Law
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving away from Earth. The velocity of the galaxies has been determined by their redshift, a shift of the light they emit toward the red end of the visible spectrum. Hubble's law is considered the first observational basis for the expansion of the universe, and today it serves as one of the pieces of evidence most often cited in support of the Big Bang model. The motion of astronomical objects due solely to this expansion is known as the Hubble flow. It is described by the equation , with ''H''0 the constant of proportionality—the Hubble constant—between the "proper distance" ''D'' to a galaxy, which can change over time, unlike the comoving distance, and its speed of separation ''v'', i.e. the derivative of proper distance with respect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperial Russia
The Russian Empire was an empire and the final period of the List of Russian monarchs, Russian monarchy from 1721 to 1917, ruling across large parts of Eurasia. It succeeded the Tsardom of Russia following the Treaty of Nystad, which ended the Great Northern War. The rise of the Russian Empire coincided with the decline of neighbouring rival powers: the Swedish Empire, the Polish–Lithuanian Commonwealth, Qajar Iran, the Ottoman Empire, and Qing dynasty, Qing China. It also held colonies in North America between 1799 and 1867. Covering an area of approximately , it remains the list of largest empires, third-largest empire in history, surpassed only by the British Empire and the Mongol Empire; it ruled over a population of 125.6 million people per the Russian Empire Census, 1897 Russian census, which was the only census carried out during the entire imperial period. Owing to its geographic extent across three continents at its peak, it featured great ethnic, linguistic, re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fighting occurring throughout Europe, the Middle East, Africa, the Pacific, and parts of Asia. An estimated 9 million soldiers were killed in combat, plus another 23 million wounded, while 5 million civilians died as a result of military action, hunger, and disease. Millions more died in genocides within the Ottoman Empire and in the 1918 influenza pandemic, which was exacerbated by the movement of combatants during the war. Prior to 1914, the European great powers were divided between the Triple Entente (comprising France, Russia, and Britain) and the Triple Alliance (containing Germany, Austria-Hungary, and Italy). Tensions in the Balkans came to a head on 28 June 1914, following the assassination of Archduke Franz Ferdin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacob Tamarkin
Jacob David Tamarkin (russian: Я́ков Дави́дович Тама́ркин, ''Yakov Davidovich Tamarkin''; 11 July 1888 – 18 November 1945) was a Russian-American mathematician best known for his work in mathematical analysis. Biography Tamarkin was born in Chernihiv, Imperial Russia to a wealthy Jewish family. His father, David Tamarkin, was a physician and his mother, Sophie Krassilschikov, was from a family of a landowner. He shares a common ancestor with the Van Leer family, sometimes spelled Von Löhr or Valar. He moved to St. Petersburg as a child and grew up there. In high school, he befriended Alexander Friedmann, a future cosmologist, with whom he wrote his first mathematics paper in 1906, and remained friends and colleagues until Friedmann's sudden death in 1925. Vladimir Smirnov was his other friend from the same gymnasium. Many years later, they coauthored a popular textbook titled "A course in higher mathematics". Tamarkin studied in St. Petersburg Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Petersburg Mining Institute
Saint Petersburg Mining University (russian: Санкт-Петербургский горный университет), is Russia's oldest technical university, and one of the oldest technical colleges in Europe. It was founded on October 21, 1773, by Empress Catherine the Great, who realised an idea proposed by Peter the Great and Mikhail Lomonosov for training engineers for the mining and metals industries. Having a strong engineering profession was seen by many Russian rulers as a vital means of maintaining Russia's status as a great power. As historian Alfred J. Rieber wrote, "The marriage of technology and central state power had a natural attraction for Peter the Great and his successors, particularly Paul I, Alexander I, and Nicholas I". All three had had a military education and seen the achievements of the engineers of revolutionary and imperial France, who had reconstructed the great highways, unified the waterways and erected buildings throughout Europe in a more las ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
