Virtual International Authority File
The Virtual International Authority File is an international authority file. It is a joint project of several national libraries and operated by the Online Computer Library Center. Discussion about having a common international authority started in the late 1990s. After a series of failed attempts to come up with a unique common authority file, the new idea was to link existing national authorities; this would present all the benefits of a common file without requiring a large investment of time and expense in the process. The project was initiated by the US Library of Congress, the German National Library and the OCLC on August 6, 2003; the Bibliothèque nationale de France joined the project on October 5, 2007. The project transitioned to being a service of the OCLC on April 4, 2012; the aim is to link the national authority files to a single virtual authority file. In this file, identical records from the different data sets are linked together. A VIAF record receives a standard data number, contains the primary "see" and "see also" records from the original records, refers to the original authority records.
The data are available for research and data exchange and sharing. Reciprocal updating uses the Open Archives Initiative Protocol for Metadata Harvesting protocol; the file numbers are being added to Wikipedia biographical articles and are incorporated into Wikidata. VIAF's clustering algorithm is run every month; as more data are added from participating libraries, clusters of authority records may coalesce or split, leading to some fluctuation in the VIAF identifier of certain authority records. Authority control Faceted Application of Subject Terminology Integrated Authority File International Standard Authority Data Number International Standard Name Identifier Wikipedia's authority control template for articles Official website VIAF at OCLC
Henry Norris Russell
Prof Henry Norris Russell ForMemRS HFRSE FRAS was an American astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung–Russell diagram. In 1923, working with Frederick Saunders, he developed Russell–Saunders coupling, known as LS coupling. Russell was born on 25 October 1877, at Oyster Bay, New York, the son of Rev Alexander Gatherer Russell and his wife, Eliza Hoxie Norris, he studied astronomy at Princeton University, obtaining his B. A. In 1897 and his doctorate in 1899, studying under Charles Augustus Young. From 1903 to 1905, he worked at the Cambridge Observatory with Arthur Robert Hinks as a research assistant of the Carnegie Institution and came under the strong influence of George Darwin, he returned to Princeton to become an instructor in astronomy, assistant professor and research professor. He was the director of the Princeton University Observatory from 1912 to 1947, he died in Princeton, New Jersey on 18 February 1957 at the age of 79. He is buried in Princeton Cemetery.
In November 1908 Russell married Lucy May Cole. They had four children, their youngest daughter, Margaret Russell, married the astronomer Frank K. Edmondson in the 1930s. Russell co-wrote an influential two-volume textbook in 1927 with Raymond Smith Dugan and John Quincy Stewart: Astronomy: A Revision of Young’s Manual of Astronomy; this became the standard astronomy textbook for about two decades. There were two volumes: the first was The Solar System and the second was Astrophysics and Stellar Astronomy; the textbook popularized the idea that a star's properties were determined by the star's mass and chemical composition, which became known as the Vogt-Russell theorem. Since a star's chemical composition changes with age, stellar evolution results. Russell dissuaded Cecilia Payne-Gaposchkin from concluding that the composition of the Sun is different from that of the Earth in her thesis, as it contradicted the accepted wisdom at the time, he realized she was correct four years after deriving the same result by different means.
In his paper Russell credited Payne with discovering that the Sun had a different chemical composition from Earth. Henry Norris Russell. "New Regularities in the Spectra of the Alkaline Earths". Astrophysical Journal. 61: 38–69. Bibcode:1925ApJ....61...38R. Doi:10.1086/142872. Henry Norris Russell. Astronomy: A Revision of Young’s Manual of Astronomy. I: The Solar System. Boston: Ginn & Co. Henry Norris Russell. "On the Composition of the Sun's Atmosphere". Astrophysical Journal. 70: 11–82. Bibcode:1929ApJ....70...11R. Doi:10.1086/143197. Henry Norris Russell. "Model Stars". Bull. Amer. Math. Soc. 43: 49–77. Doi:10.1090/S0002-9904-1937-06492-5. MR 1563489. Fellow of the American Academy of Arts and Sciences Gold Medal of the Royal Astronomical Society Lalande Prize Henry Draper Medal from the National Academy of Sciences Bruce Medal Rumford Prize Franklin Medal Janssen Medal from the French Academy of Sciences Foreign Member of the Royal Society Honorary Fellow of the Royal Society of Edinburgh Henry Norris Russell Lectureship asteroid 1762 Russell
Roskilde, located 30 km west of Copenhagen on the Danish island of Zealand, is the main city in Roskilde Municipality. With a population of 50,046, the city is a business and educational centre for the region and the 10th largest city in Denmark. Roskilde is governed by the administrative council of Roskilde Municipality. Roskilde has a long history, dating from the pre-Christian Viking Age, its UNESCO-listed Gothic cathedral, now housing 39 tombs of the Danish monarchs, was completed in 1275, becoming a focus of religious influence until the Reformation. With the development of the rail network in the 19th century, Roskilde became an important hub for traffic with Copenhagen, by the end of the century, there were tobacco factories, iron foundries and machine shops. Among the largest private sector employers today are the IT firm BEC and GPI, specializing in plastics; the Risø research facility is becoming a major employer, extending interest in sustainable energy to the clean technology sphere.
The local university, founded in 1972, the historic Cathedral School, the Danish Meat Trade College, established in 1964, are educational institutions of note. Roskilde has a large local hospital, expanded and modernized since it was opened in 1855, it is now active in the research sphere. The Sankt Hans psychiatric hospital serves the Capital Region with specialized facilities for forensic psychiatry; the cathedral and the Viking Ship Museum, which contains the well-preserved remains of five 11th-century ships, attract more than 100,000 visitors annually. In addition to its internationally recognized tourist attractions and its annual rock festival, Roskilde is popular with shoppers thanks to its two centrally located pedestrian streets complete with restaurants, cafés, a variety of shops; the city is home to the FC Roskilde football club which play in the Danish 1st Division, the Roskilde Vikings RK rugby club, the rowing club, Roskilde Roklub. In the 1970s, the city benefited from the opening of the university and from the completion of the Holbæk Motorway connecting it to Copenhagen.
Roskilde has the oldest operational railway station in Denmark, with connections across Zealand as well as with Falster and Jutland. The local airport opened in 1973 serving light aircraft for business use and flight instruction. Among the city's notable citizens are Absalon, the bishop who founded Copenhagen in the 12th century, L. A. Ring, the symbolist painter who gained fame in the 1880s, the writer Lise Nørgaard who wrote the popular Danish TV series Matador in 1978 and the rower Thomas Ebert who became an Olympic gold medallist in 2004. Roskilde, which developed as the hub of the Viking land and sea trade routes over a thousand years ago, is one of Denmark's oldest cities. From the 11th century until 1443, it was the capital of Denmark. By the Middle Ages, with the support of kings and bishops, it had become one of the most important centres in Scandinavia; the Saxo Grammaticus and other early sources associate the name Roskilde with the legendary King Roar who lived there in the 6th century.
According to Adam of Bremen and the Saxo Grammaticus, Roskilde was founded in the 980s by Harald Bluetooth. On high ground above the harbour, he built a wooden church consecrated to the Holy Trinity as well as a royal residence nearby. Although no traces of these buildings have been discovered, in 1997 archaeologists found the remains of Viking ships in the Isefjord, the oldest of, dated to 1030. At the time, there were two churches in the area: St Jørgensbjerg, an early stone church, a wooden church discovered under today's St Ib's Church. Harald was buried in the wooden church. In 1020, King Canute elevated Roskilde to a bishopric. Absalon, the Danish bishop, had a brick church built on the site of Harald's church in 1170. Today's cathedral was completed in 1275 after five of Absalon's successors had contributed to its construction; as a result of Absalon's influence, many other churches were built in the vicinity, making Roskilde the most important town in Zealand. Coins were minted there from the 11th to the 14th century.
In 1150, Sweyn Grathe built a moat around the city. The Roskilde bishops owned large areas of land in the region including, from 1186, Havn on the Øresund which became Copenhagen. By the time of the Danish Reformation in 1536, there were 12 churches and five monasteries in the city, it is not clear when Roskilde became a market town but it was enjoying trading privileges under King Eric II who reigned from 1134 to 1137. These privileges were established when the Roskilde City Council granted market town status to other towns on Zealand on 15 June 1268. By that time, it was the largest and most important town in Denmark. In 1370, the city owned 2,600 farms throughout Zealand; the Reformation brought Roskilde's development to an abrupt stop. While the cathedral continued to be the preferred location for the entombment of the Danish monarchs, most of the other religious institutions disappeared. For the next three centuries, the city suffered a series of disasters including the effects of the Dano-Swedish War which terminated with the Treaty of Roskilde in 1658, the plague in 1710 and 1711, a series of fires in 1730.
Conditions improved in 1835 when the city became the Assembly of the Estates of the Realm and in 1847 with the railway connecting Copenhagen and Roskilde. With the development of the rail network, Roskilde became an important hub for traffic with Copenhagen. In the 1870s and 1880s, the harbour was extended attracting industria
The Amor asteroids are a group of near-Earth asteroids named after the archetype object 1221 Amor. The orbital perihelion of these objects is close to, but greater than, the orbital aphelion of Earth, with most Amors crossing the orbit of Mars; the Amor asteroid 433 Eros was the first asteroid to be orbited and landed upon by a robotic space probe. The orbital characteristics that define an asteroid as being in the Amor group are: The orbital period is greater than one year; as of 2019 there are 7427 known Amor asteroids. 1153 are numbered, 75 of them are named. An outer Earth-grazer asteroid is an asteroid, beyond Earth's orbit, but which can get closer to the Sun than Earth's aphelion, not closer than Earth's perihelion. Outer Earth-grazer asteroids are split between Apollo asteroids. Using the definition of Amor asteroids above, "Earth grazers" that never get closer to the Sun than Earth does are Amors, whereas those that do are Apollos. To be considered a hazardous asteroid, an object's orbit must, at some point, come within 0.05 AU of Earth's orbit, the object itself must be sufficiently large/massive to cause significant regional damage if it impacted Earth.
Most PHAs are either Aten asteroids or Apollo asteroids, but one tenth of PHAs are Amor asteroids. A hazardous Amor asteroid therefore must have a perihelion of less than 1.05 AU. 20% of the known Amors meet this requirement, about a fifth of those are PHAs. The fifty known Amor PHAs include the named objects 2061 Anza, 3122 Florence, 3908 Nyx, 3671 Dionysus; this is a non-static list of named Amor asteroids. Amor asteroid records Alinda family Arjuna asteroid List of minor planets List of Amor minor planets
Asteroids are minor planets of the inner Solar System. Larger asteroids have been called planetoids; these terms have been applied to any astronomical object orbiting the Sun that did not resemble a planet-like disc and was not observed to have characteristics of an active comet such as a tail. As minor planets in the outer Solar System were discovered they were found to have volatile-rich surfaces similar to comets; as a result, they were distinguished from objects found in the main asteroid belt. In this article, the term "asteroid" refers to the minor planets of the inner Solar System including those co-orbital with Jupiter. There exist millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets; the vast majority of known asteroids orbit within the main asteroid belt located between the orbits of Mars and Jupiter, or are co-orbital with Jupiter. However, other orbital families exist with significant populations, including the near-Earth objects.
Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, S-type. These were named after and are identified with carbon-rich and silicate compositions, respectively; the sizes of asteroids varies greatly. Asteroids are differentiated from meteoroids. In the case of comets, the difference is one of composition: while asteroids are composed of mineral and rock, comets are composed of dust and ice. Furthermore, asteroids formed closer to the sun; the difference between asteroids and meteoroids is one of size: meteoroids have a diameter of one meter or less, whereas asteroids have a diameter of greater than one meter. Meteoroids can be composed of either cometary or asteroidal materials. Only one asteroid, 4 Vesta, which has a reflective surface, is visible to the naked eye, this only in dark skies when it is favorably positioned. Small asteroids passing close to Earth may be visible to the naked eye for a short time; as of October 2017, the Minor Planet Center had data on 745,000 objects in the inner and outer Solar System, of which 504,000 had enough information to be given numbered designations.
The United Nations declared 30 June as International Asteroid Day to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, Russian Federation, on 30 June 1908. In April 2018, the B612 Foundation reported "It's 100 percent certain we'll be hit, but we're not 100 percent sure when." In 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, has developed and released the "National Near-Earth Object Preparedness Strategy Action Plan" to better prepare. According to expert testimony in the United States Congress in 2013, NASA would require at least five years of preparation before a mission to intercept an asteroid could be launched; the first asteroid to be discovered, was considered to be a new planet.
This was followed by the discovery of other similar bodies, with the equipment of the time, appeared to be points of light, like stars, showing little or no planetary disc, though distinguishable from stars due to their apparent motions. This prompted the astronomer Sir William Herschel to propose the term "asteroid", coined in Greek as ἀστεροειδής, or asteroeidēs, meaning'star-like, star-shaped', derived from the Ancient Greek ἀστήρ astēr'star, planet'. In the early second half of the nineteenth century, the terms "asteroid" and "planet" were still used interchangeably. Overview of discovery timeline: 10 by 1849 1 Ceres, 1801 2 Pallas – 1802 3 Juno – 1804 4 Vesta – 1807 5 Astraea – 1845 in 1846, planet Neptune was discovered 6 Hebe – July 1847 7 Iris – August 1847 8 Flora – October 1847 9 Metis – 25 April 1848 10 Hygiea – 12 April 1849 tenth asteroid discovered 100 asteroids by 1868 1,000 by 1921 10,000 by 1989 100,000 by 2005 ~700,000 by 2015 Asteroid discovery methods have improved over the past two centuries.
In the last years of the 18th century, Baron Franz Xaver von Zach organized a group of 24 astronomers to search the sky for the missing planet predicted at about 2.8 AU from the Sun by the Titius-Bode law because of the discovery, by Sir William Herschel in 1781, of the planet Uranus at the distance predicted by the law. This task required that hand-drawn sky charts be prepared for all stars in the zodiacal band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would be spotted; the expected motion of the missing planet was about 30 seconds of arc per hour discernible by observers. The first object, was not discovered by a member of the group, but rather by accident in 1801 by Giuseppe Piazzi, director of the observatory of Palermo in Sicily, he discovered a new star-like object in Taurus and followed the displacement of this object during several nights. That year, Carl Friedrich Gauss used these observations to calculate the orbit of this unknown object, found to be between the planets Mars and Jupiter.
Piazzi named it after Ceres, the Roman goddess of agriculture. Three other asteroids (2 Pallas, 3 Juno, 4 Ves
Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics and chemistry in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, stars, nebulae and comets. More all phenomena that originate outside Earth's atmosphere are within the purview of astronomy. A related but distinct subject is physical cosmology, the study of the Universe as a whole. Astronomy is one of the oldest of the natural sciences; the early civilizations in recorded history, such as the Babylonians, Indians, Nubians, Chinese and many ancient indigenous peoples of the Americas, performed methodical observations of the night sky. Astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, but professional astronomy is now considered to be synonymous with astrophysics. Professional astronomy is split into theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, analyzed using basic principles of physics.
Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain observational results and observations being used to confirm theoretical results. Astronomy is one of the few sciences in which amateurs still play an active role in the discovery and observation of transient events. Amateur astronomers have made and contributed to many important astronomical discoveries, such as finding new comets. Astronomy means "law of the stars". Astronomy should not be confused with astrology, the belief system which claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin, they are now distinct. Both of the terms "astronomy" and "astrophysics" may be used to refer to the same subject. Based on strict dictionary definitions, "astronomy" refers to "the study of objects and matter outside the Earth's atmosphere and of their physical and chemical properties," while "astrophysics" refers to the branch of astronomy dealing with "the behavior, physical properties, dynamic processes of celestial objects and phenomena."
In some cases, as in the introduction of the introductory textbook The Physical Universe by Frank Shu, "astronomy" may be used to describe the qualitative study of the subject, whereas "astrophysics" is used to describe the physics-oriented version of the subject. However, since most modern astronomical research deals with subjects related to physics, modern astronomy could be called astrophysics; some fields, such as astrometry, are purely astronomy rather than astrophysics. Various departments in which scientists carry out research on this subject may use "astronomy" and "astrophysics" depending on whether the department is affiliated with a physics department, many professional astronomers have physics rather than astronomy degrees; some titles of the leading scientific journals in this field include The Astronomical Journal, The Astrophysical Journal, Astronomy and Astrophysics. In early historic times, astronomy only consisted of the observation and predictions of the motions of objects visible to the naked eye.
In some locations, early cultures assembled massive artifacts that had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops and in understanding the length of the year. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye; as civilizations developed, most notably in Mesopotamia, Persia, China and Central America, astronomical observatories were assembled and ideas on the nature of the Universe began to develop. Most early astronomy consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, the nature of the Sun and the Earth in the Universe were explored philosophically; the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the geocentric model of the Ptolemaic system, named after Ptolemy.
A important early development was the beginning of mathematical and scientific astronomy, which began among the Babylonians, who laid the foundations for the astronomical traditions that developed in many other civilizations. The Babylonians discovered. Following the Babylonians, significant advances in astronomy were made in ancient Greece and the Hellenistic world. Greek astronomy is characterized from the start by seeking a rational, physical explanation for celestial phenomena. In the 3rd century BC, Aristarchus of Samos estimated the size and distance of the Moon and Sun, he proposed a model of the Solar System where the Earth and planets rotated around the Sun, now called the heliocentric model. In the 2nd century BC, Hipparchus discovered precession, calculated the size and distance of the Moon and inven
Karl Schwarzschild was a German physicist and astronomer. He was the father of astrophysicist Martin Schwarzschild. 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, 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 from the autoimmune disease pemphigus, which he developed while at the Russian front. Various forms of the disease affect people of Ashkenazi Jewish origin. Asteroid 837 Schwarzschilda is named in his honour, as is the large crater Schwarzschild, on the far side of the Moon. Schwarzschild was born in Frankfurt am Main to Jewish parents.
His father was active in the business community of the city, the family had ancestors in the city dating back to the sixteenth century. Karl attended a Jewish primary school until 11 years of age, he was something of a child prodigy, having two papers on binary orbits published before he was sixteen. He studied at Strasbourg and Munich, obtaining his doctorate in 1896 for a work on Henri Poincaré's theories. From 1897, he worked as assistant at the Kuffner Observatory in Vienna. From 1901 until 1909 he was a professor at the prestigious institute at Göttingen, where he had the opportunity to work with some significant figures, including David Hilbert and Hermann Minkowski. Schwarzschild became the director of the observatory in Göttingen, he married Else Rosenbach, the daughter of a professor of surgery at Göttingen, in 1909, that year moved to Potsdam, where he took up the post of director of the Astrophysical Observatory. This was the most prestigious post available for an astronomer in Germany.
He and Else had three children, Agathe and Alfred. From 1912, Schwarzschild was a member of the Prussian Academy of Sciences. At the outbreak of World War I in 1914 he joined the German army, despite being over 40 years old, he served on both the eastern fronts, rising to the rank of lieutenant in the artillery. While serving on the front in Russia in 1915, he began to suffer from a rare and painful autoimmune skin disease called pemphigus, he managed to write three outstanding papers, two on the theory of relativity and one on quantum theory. His papers on relativity produced the first exact solutions to the Einstein field equations, a minor modification of these results gives the well-known solution that now bears his name — the Schwarzschild metric. Schwarzschild's struggle with pemphigus may have led to his death on May 11, 1916. Thousands of dissertations and books have since been devoted to the study of Schwarzschild's solutions to the Einstein field equations. However, although Schwarzschild's best known work lies in the area of general relativity, his research interests were broad, including work in celestial mechanics, observational stellar photometry, quantum mechanics, instrumental astronomy, stellar structure, stellar statistics, Halley's comet, spectroscopy.
Some of his particular achievements include measurements of variable stars, using photography, the improvement of optical systems, through the perturbative investigation of geometrical aberrations. While at Vienna in 1897, Schwarzschild developed a formula, now known as the Schwarzschild law, to calculate the optical density of photographic material, it involved an exponent now known as the Schwarzschild exponent, the p in the formula: i = f. This formula was important for enabling more accurate photographic measurements of the intensities of faint astronomical sources. According to Wolfgang Pauli, Schwarzschild is the first to introduce the correct Lagrangian formalism of the electromagnetic field as S = ∫ d V + ∫ ρ d V where E →, H → are the electric and magnetic field, A → is the vector potential and ϕ is the electric potential, he introduced a field free variational formulation of electrodynamics based only on the world line of particles as S = ∑ i m i ∫ C i d s i + 1 2 ∑