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of skin and other soft tissues are rare. Rebuilding a complete skeleton by comparing the size and morphology of bones to those of similar, better- known species is an inexact art, and reconstructing the muscles and other organs of the living animal is, at best, a process of educated guesswork. The tallest and heaviest dinosaur known from good skeletons is" Giraffatitan brancai"( previously classified as a species of" Brachiosaurus"). Its remains were discovered in Tanzania between 1907 and 1912. Bones from several similar- sized individuals were incorporated into the skeleton now mounted and on display at the Museum für Naturkunde in Berlin; this mount is tall and long, and would have belonged to an animal that weighed between and kilograms( and lb). The longest complete dinosaur is the long" Diplodocus", which was discovered in Wyoming in the United States and displayed in Pittsburgh' s Carnegie Museum of Natural History in 1907. The longest dinosaur known from good fossil material is the" Patagotitan": the skeleton mount in the American Museum of Natural History in New York is long. The Museo Municipal Carmen Funes in Plaza Huincul, Argentina, has an" Argentinosaurus" reconstructed skeleton mount that is long. There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils.Mostofthelargestherbivorousspecimensonrecordwerediscoveredinthe1970s or later, and include the massive" Argentinosaurus", which may have weighed to kilograms( 90 to 110 short tons) and reached lengths of; some of the longest were the long" Diplodocus hallorum"( formerly" Seismosaurus"), the long" Supersaurus", and long" Patagotitan"; and the tallest, the tall" Sauroposeidon", which could have reached a sixth- floor window. The heaviest and longest dinosaur may have been" Maraapunisaurus", known only from a now lost partial vertebral neural arch described in 1878. Extrapolating from the illustration of this bone, the animal may have been long and weighed kg( lb). However, as no further evidence of sauropods of this size has been found, and the discoverer, Cope, had made typographic errors before, it is likely to have been an extreme overestimation. The largest carnivorous dinosaur was" Spinosaurus", reaching a length of, and weighing. Other large carnivorous theropods included" Giganotosaurus"," Carcharodontosaurus" and" Tyrannosaurus"." Therizinosaurus" and" Deinocheirus" were among the tallest of the theropods. The largest ornithischian dinosaur was probably the hadrosaurid" Shantungosaurus giganteus" which measured. The largest individuals may have weighed as much as. The smallest dinosaur known is the bee hummingbird, with a length of only and mass of around. The smallest known non- avialan dinosaurs were about the size of pigeons and were those theropods most closely related to birds. For example," Anchiornis huxleyi" is currently the smallest non- avialan dinosaur described from an adult specimen, with an estimated weight of and a total skeletal length of. The smallest herbivorous non- avialan dinosaurs included" Microceratus" and" Wannanosaurus", at about long each. Behavior. Many modern birds are highly social, often found living in flocks. There is general agreement that some behaviors that are common in birds, as well as in crocodiles( closest living relatives of birds), were also common among extinct dinosaur groups. Interpretations of behavior in | fossil species are generally based |
on the pose of skeletons and their habitat, computer simulations of their biomechanics, and comparisons with modern animals in similar ecological niches. The first potential evidence for herding or flocking as a widespread behavior common to many dinosaur groups in addition to birds was the 1878 discovery of 31" Iguanodon", ornithischians that were then thought to have perished together in Bernissart, Belgium, after they fell into a deep, flooded sinkhole and drowned. Other mass- death sites have been discovered subsequently. Those, along with multiple trackways, suggest that gregarious behavior was common in many early dinosaur species. Trackways of hundreds or even thousands of herbivores indicate that duck- billed( hadrosaurids) may have moved in great herds, like the American bison or the African Springbok. Sauropod tracks document that these animals traveled in groups composed of several different species, at least in Oxfordshire, England, although there is no evidence for specific herd structures. Congregating into herds may have evolved for defense, for migratory purposes, or to provide protection for young. There is evidence that many types of slow- growing dinosaurs, including various theropods, sauropods, ankylosaurians, ornithopods, and ceratopsians, formed aggregations of immature individuals. One example is a site in Inner Mongolia that has yielded remains of over 20" Sinornithomimus", from one to seven years old. This assemblage is interpreted as a social group that was trapped in mud. The interpretation of dinosaurs as gregarious has also extended to depicting carnivorous theropods as pack hunters working together to bring down large prey. However, this lifestyle is uncommon among modern birds, crocodiles, and other reptiles, and the taphonomic evidence suggesting mammal- like pack hunting in such theropods as" Deinonychus" and" Allosaurus" can also be interpreted as the results of fatal disputes between feeding animals, as is seen in many modern diapsid predators. The crests and frills of some dinosaurs, like the marginocephalians, theropods and lambeosaurines, may have been too fragile to be used for active defense, and so they were likely used for sexual or aggressive displays, though little is known about dinosaur mating and territorialism. Head wounds from bites suggest that theropods, at least, engaged in active aggressive confrontations. From a behavioral standpoint, one of the most valuable dinosaur fossils was discovered in the Gobi Desert in 1971. It included a" Velociraptor" attacking a" Protoceratops", providing evidence that dinosaurs did indeed attack each other. Additional evidence for attacking live prey is the partially healed tail of an" Edmontosaurus", a hadrosaurid dinosaur; the tail is damaged in such a way that shows the animal was bitten by a tyrannosaur but survived. Cannibalism amongst some species of dinosaurs was confirmed by tooth marks found in Madagascar in 2003, involving the theropod" Majungasaurus". Comparisons between the scleral rings of dinosaurs and modern birds and reptiles have been used to infer daily activity patterns of dinosaurs. Although it has been suggested that most dinosaurs were active during the day, these comparisons have shown that small predatory dinosaurs such as dromaeosaurids," Juravenator", and" Megapnosaurus" were likely nocturnal. Large and medium- sized herbivorous and omnivorous dinosaurs such as ceratopsians, sauropodomorphs, hadrosaurids, | ornithomimosaurs may have been cathemeral, |
active during short intervals throughout the day, although the small ornithischian" Agilisaurus" was inferred to be diurnal. Based on fossil evidence from dinosaurs such as" Oryctodromeus", some ornithischian species seem to have led a partially fossorial( burrowing) lifestyle. Many modern birds are arboreal( tree climbing), and this was also true of many Mesozoic birds, especially the enantiornithines. While some early bird- like species may have already been arboreal as well( including dromaeosaurids) such as" Microraptor") most non- avialan dinosaurs seem to have relied on land- based locomotion. A good understanding of how dinosaurs moved on the ground is key to models of dinosaur behavior; the science of biomechanics, pioneered by Robert McNeill Alexander, has provided significant insight in this area. For example, studies of the forces exerted by muscles and gravity on dinosaurs' skeletal structure have investigated how fast dinosaurs could run, whether diplodocids could create sonic booms via whip- like tail snapping, and whether sauropods could float. Communication. Modern birds are known to communicate using visual and auditory signals, and the wide diversity of visual display structures among fossil dinosaur groups, such as horns, frills, crests, sails, and feathers, suggests that visual communication has always been important in dinosaur biology. Reconstruction of the plumage color of" Anchiornis", suggest the importance of color in visual communication in non- avian dinosaurs. The evolution of dinosaur vocalization is less certain. Paleontologist Phil Senter has suggested that non- avian dinosaurs relied mostly on visual displays and possibly non- vocal acoustic sounds like hissing, jaw grinding or clapping, splashing and wing beating( possible in winged maniraptoran dinosaurs). He states they were unlikely to have been capable of vocalizing since their closest relatives, crocodilians and birds, use different means to vocalize, the former via the larynx and the latter through the unique syrinx, suggesting they evolved independently and their common ancestor was mute. The earliest remains of a syrinx, which has enough mineral content for fossilization, was found in a specimen of the duck- like" Vegavis iaai" dated 69– 66 million years ago, and this organ is unlikely to have existed in non- avian dinosaurs. However, in contrast to Senter, other researchers have suggested that dinosaurs could vocalize and that the syrinx- based vocal system of birds evolved from a larynx- based one, rather than the two systems evolving independently. A 2016 study suggests that some dinosaurs produced closed mouth vocalizations like cooing, hooting and booming. These occur in both reptiles and birds and involve inflating the esophagus or tracheal pouches. Such vocalizations evolved independently in extant archosaurs numerous times, following increases in body size. The crests of the Lambeosaurini and nasal chambers of ankylosaurids have been suggested to have functioned in vocal resonance, though Senter stated that the presence of resonance chambers in some dinosaurs is not necessarily evidence of vocalization as modern snakes have such chambers which intensify their hisses. Reproductive biology. All dinosaurs laid amniotic eggs. Dinosaur eggs were usually laid in a nest. Most species create somewhat elaborate nests which can be cups, domes, plates, beds scrapes, mounds, or burrows. Some species of | modern bird have no nests; |
the cliff- nesting common guillemot lays its eggs on bare rock, and male emperor penguins keep eggs between their body and feet. Primitive birds and many non- avialan dinosaurs often lay eggs in communal nests, with males primarily incubating the eggs. While modern birds have only one functional oviduct and lay one egg at a time, more primitive birds and dinosaurs had two oviducts, like crocodiles. Some non- avialan dinosaurs, such as" Troodon", exhibited iterative laying, where the adult might lay a pair of eggs every one or two days, and then ensured simultaneous hatching by delaying brooding until all eggs were laid. When laying eggs, females grow a special type of bone between the hard outer bone and the marrow of their limbs. This medullary bone, which is rich in calcium, is used to make eggshells. A discovery of features in a" Tyrannosaurus" skeleton provided evidence of medullary bone in extinct dinosaurs and, for the first time, allowed paleontologists to establish the sex of a fossil dinosaur specimen. Further research has found medullary bone in the carnosaur" Allosaurus" and the ornithopod" Tenontosaurus". Because the line of dinosaurs that includes" Allosaurus" and" Tyrannosaurus" diverged from the line that led to" Tenontosaurus" very early in the evolution of dinosaurs, this suggests that the production of medullary tissue is a general characteristic of all dinosaurs. Another widespread trait among modern birds( but see below in regards to fossil groups and extant megapodes) is parental care for young after hatching. Jack Horner' s 1978 discovery of a" Maiasaura"(" good mother lizard") nesting ground in Montana demonstrated that parental care continued long after birth among ornithopods. A specimen of the oviraptorid" Citipati osmolskae" was discovered in a chicken- like brooding position in 1993, which may indicate that they had begun using an insulating layer of feathers to keep the eggs warm. An embryo of the basal sauropodomorph" Massospondylus" was found without teeth, indicating that some parental care was required to feed the young dinosaurs. Trackways have also confirmed parental behavior among ornithopods from the Isle of Skye in northwestern Scotland. However, there is ample evidence of precociality or superprecociality among many dinosaur species, particularly theropods. For instance, non- ornithuromorph birds have been abundantly demonstrated to have had slow growth rates, megapode- like egg burying behavior and the ability to fly soon after birth. Both" Tyrannosaurus" and" Troodon" had juveniles with clear superprecociality and likely occupying different ecological niches than the adults. Superprecociality has been inferred for sauropods. Genital structures are unlikely to fossilize as they lack scales that may allow preservation via pigmentation or residual calcium phosphate salts. In 2021, the best preserved specimen of a dinosaur' s cloacal vent exterior was described for" Psittacosaurus", demonstrating lateral swellings similar to crocodylian musk glands used in social displays by both sexes and pigmented regions which could also reflect a signalling function. However, this specimen on its own does not offer enough information to determine whether this dinosaur had sexual signalling functions; it only supports the possibility. Cloacal visual signalling can occur in either males or females in | living birds, making it unlikely |
to be useful to determine sex for extinct dinosaurs. Physiology. Because both modern crocodilians and birds have four- chambered hearts( albeit modified in crocodilians), it is likely that this is a trait shared by all archosaurs, including all dinosaurs. While all modern birds have high metabolisms and are endothermic(" warm- blooded"),avigorousdebatehasbeenongoingsincethe1960s regarding how far back in the dinosaur lineage this trait extended. Various researchers have supported dinosaurs as being endothermic, ectothermic(" cold- blooded"), or somewhere in between. An emerging consensus among researchers is that, while different lineages of dinosaurs would have had different metabolisms, most of them had higher metabolic rates than other reptiles but lower than living birds and mammals, which is termed mesothermy by some. Evidence from crocodiles and their extinct relatives suggests that such elevated metabolisms could have developed in the earliest archosaurs, which were the common ancestors of dinosaurs and crocodiles. After non- avian dinosaurs were discovered, paleontologists first posited that they were ectothermic. This was used to imply that the ancient dinosaurs were relatively slow, sluggish organisms, even though many modern reptiles are fast and light- footed despite relying on external sources of heat to regulate their body temperature. The idea of dinosaurs as ectothermic remained a prevalent view until Robert T. Bakker, an early proponent of dinosaur endothermy, published an influential paper on the topic in 1968. Bakker specifically used anatomical and ecological evidence to argue that sauropods, which had hitherto been depicted as sprawling aquatic animals with their tails dragging on the ground, were endotherms that lived vigorous, terrestrial lives. In 1972, Bakker expanded on his arguments based on energy requirements and predator- prey ratios. This was one of the seminal results that led to the Dinosaur Renaissance( see). One of the greatest contributions to the modern understanding of dinosaur physiology has been paleohistology, the study of microscopic tissue structure in dinosaurs.Fromthe1960s forward, Armand de Ricqlès suggested that the presence of fibrolamellar bone— bony tissue with an irregular, fibrous texture and filled with blood vessels— was indicative of consistently fast growth and therefore endothermy. Fibrolamellar bone was common in both dinosaurs and pterosaurs, though not universally present. This has led to a significant body of work in reconstructing growth curves and modeling the evolution of growth rates across various dinosaur lineages, which has suggested overall that dinosaurs grew faster than living reptiles. Other lines of evidence suggesting endothermy include the presence of feathers and other types of body coverings in many lineages( see); more consistent ratios of the isotope oxygen- 18 in bony tissue compared to ectotherms, particularly as latitude and thus air temperature varied, which suggests stable internal temperatures( although these ratios can be altered during fossilization); and the discovery of polar dinosaurs, which lived in Australia, Antarctica, and Alaska when these places would have had cool, temperate climates. In saurischian dinosaurs, higher metabolisms were supported by the evolution of the avian respiratory system, characterized by an extensive system of air sacs that extended the lungs and invaded many of the bones in the skeleton, making them hollow. Such respiratory systems, which may have | appeared in the earliest saurischians, |
would have provided them with more oxygen compared to a mammal of similar size, while also having a larger resting tidal volume and requiring a lower breathing frequency, which would have allowed them to sustain higher activity levels. The rapid airflow would also have been an effective cooling mechanism, which in conjunction with a lower metabolic rate would have prevented large sauropods from overheating. These traits may have enabled sauropods to grow quickly to gigantic sizes. Sauropods may also have benefitted from their size— their small surface area to volume ratio meant that they would have been able to thermoregulate more easily, a phenomenon termed gigantothermy. Like other reptiles, dinosaurs are primarily uricotelic, that is, their kidneys extract nitrogenous wastes from their bloodstream and excrete it as uric acid instead of urea or ammonia via the ureters into the intestine. This would have helped them to conserve water. In most living species, uric acid is excreted along with feces as a semisolid waste. However, at least some modern birds( such as hummingbirds) can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. This material, as well as the output of the intestines, emerges from the cloaca. In addition, many species regurgitate pellets, and fossil pellets are known as early as the Jurassic from" Anchiornis". The size and shape of the brain can be partly reconstructed based on the surrounding bones. In 1896, Marsh calculated ratios between brain weight and body weight of seven species of dinosaurs, showing that the brain of dinosaurs was proportionally smaller than in today' s crocodiles, and that the brain of" Stegosaurus" was smaller than in any living land vertebrate. This contributed to the widespread public notion of dinosaurs as being sluggish and extraordinarily stupid. Harry Jerison, in 1973, showed that proportionally smaller brains are expected at larger body sizes, and that brain size in dinosaurs was not smaller than expected when compared to living reptiles. Later research showed that relative brain size progressively increased during the evolution of theropods, with the highest intelligence– comparable to that of modern birds– calculated for the troodontid" Troodon". Origin of birds. The possibility that dinosaurs were the ancestors of birds was first suggested in 1868 by Thomas Henry Huxley. After the work of GerhardHeilmannintheearly20th century, the theory of birds as dinosaur descendants was abandoned in favor of the idea of them being descendants of generalized thecodonts, with the key piece of evidence being the supposed lack of clavicles in dinosaurs. However, as later discoveries showed, clavicles( or a single fused wishbone, which derived from separate clavicles) were not actually absent; they had been found as early as 1924 in" Oviraptor", but misidentified as an interclavicle.Inthe1970s, Ostrom revived the dinosaur– bird theory, which gained momentum in the coming decades with the advent of cladistic analysis, and a great increase in the discovery of small theropods and early birds. Of particular note have been the fossils of the Yixian Formation, where a variety of theropods and early birds have been found, often with feathers of some type. Birds share over a | hundred distinct anatomical features with |
theropod dinosaurs, which are now generally accepted to have been their closest ancient relatives. They are most closely allied with maniraptoran coelurosaurs. A minority of scientists, most notably Alan Feduccia and Larry Martin, have proposed other evolutionary paths, including revised versions of Heilmann' s basal archosaur proposal, or that maniraptoran theropods are the ancestors of birds but themselves are not dinosaurs, only convergent with dinosaurs. Feathers. Feathers are one of the most recognizable characteristics of modern birds, and a trait that was also shared by several non- avian dinosaurs. Based on the current distribution of fossil evidence, it appears that feathers were an ancestral dinosaurian trait, though one that may have been selectively lost in some species. Direct fossil evidence of feathers or feather- like structures has been discovered in a diverse array of species in many non- avian dinosaur groups, both among saurischians and ornithischians. Simple, branched, feather- like structures are known from heterodontosaurids, primitive neornithischians, and theropods, and primitive ceratopsians. Evidence for true, vaned feathers similar to the flight feathers of modern birds has been found only in the theropod subgroup Maniraptora, which includes oviraptorosaurs, troodontids, dromaeosaurids, and birds. Feather- like structures known as pycnofibres have also been found in pterosaurs, suggesting the possibility that feather- like filaments may have been common in the bird lineage and evolved before the appearance of dinosaurs themselves. Research into the genetics of American alligators has also revealed that crocodylian scutes do possess feather- keratins during embryonic development, but these keratins are not expressed by the animals before hatching." Archaeopteryx" was the first fossil found that revealed a potential connection between dinosaurs and birds. It is considered a transitional fossil, in that it displays features of both groups. Brought to light just two years after Charles Darwin' s seminal" On the Origin of Species"( 1859), its discovery spurred the nascent debate between proponents of evolutionary biology and creationism. This early bird is so dinosaur- like that, without a clear impression of feathers in the surrounding rock, at least one specimen was mistaken for the small theropod" Compsognathus".Sincethe1990s, a number of additional feathered dinosaurs have been found, providing even stronger evidence of the close relationship between dinosaurs and modern birds. Most of these specimens were unearthed in the lagerstätte of the Yixian Formation, Liaoning, northeastern China, which was part of an island continent during the Cretaceous. Though feathers have been found in only a few locations, it is possible that non- avian dinosaurs elsewhere in the world were also feathered. The lack of widespread fossil evidence for feathered non- avian dinosaurs may be because delicate features like skin and feathers are seldom preserved by fossilization and thus often absent from the fossil record. The description of feathered dinosaurs has not been without controversy; perhaps the most vocal critics have been Alan Feduccia and Theagarten Lingham- Soliar, who have proposed that some purported feather- like fossils are the result of the decomposition of collagenous fiber that underlaid the dinosaurs' skin, and that maniraptoran dinosaurs with vaned feathers were not actually dinosaurs, but convergent with dinosaurs. However, | their views have for the |
most part not been accepted by other researchers, to the point that the scientific nature of Feduccia' s proposals has been questioned. Skeleton. Because feathers are often associated with birds, feathered dinosaurs are often touted as the missing link between birds and dinosaurs. However, the multiple skeletal features also shared by the two groups represent another important line of evidence for paleontologists. Areas of the skeleton with important similarities include the neck, pubis, wrist( semi- lunate carpal), arm and pectoral girdle, furcula( wishbone), and breast bone. Comparison of bird and dinosaur skeletons through cladistic analysis strengthens the case for the link. Soft anatomy. Large meat- eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to a 2005 investigation led by Patrick M. O' Connor. The lungs of theropod dinosaurs( carnivores that walked on two legs and had bird- like feet) likely pumped air into hollow sacs in their skeletons, as is the case in birds." What was once formally considered unique to birds was present in some form in the ancestors of birds", O' Connor said. In 2008, scientists described" Aerosteon riocoloradensis", the skeleton of which supplies the strongest evidence to date of a dinosaur with a bird- like breathing system. CT scanning of" Aerosteon"' s fossil bones revealed evidence for the existence of air sacs within the animal' s body cavity. Behavioral evidence. Fossils of the troodonts" Mei" and" Sinornithoides" demonstrate that some dinosaurs slept with their heads tucked under their arms. This behavior, which may have helped to keep the head warm, is also characteristic of modern birds. Several deinonychosaur and oviraptorosaur specimens have also been found preserved on top of their nests, likely brooding in a bird- like manner. The ratio between egg volume and body mass of adults among these dinosaurs suggest that the eggs were primarily brooded by the male, and that the young were highly precocial, similar to many modern ground- dwelling birds. Some dinosaurs are known to have used gizzard stones like modern birds. These stones are swallowed by animals to aid digestion and break down food and hard fibers once they enter the stomach. When found in association with fossils, gizzard stones are called gastroliths. Extinction of major groups. All non- avian dinosaurs and most lineages of birds became extinct in a mass extinction event, called the Cretaceous– Paleogene( K- Pg) extinction event, at the end of the Cretaceous period. Above the Cretaceous– Paleogene boundary, which has been dated to 66. 038± 0. 025 million years ago, fossils of non- avian dinosaurs disappear abruptly; the absence of dinosaur fossils was historically used to assign rocks to the ensuing Cenozoic. The nature of the event that caused this mass extinction has been extensively studiedsincethe1970s, leading to the development of two mechanisms that are thought to have played major roles: an extraterrestrial impact event in the Yucatán Peninsula, along with flood basalt volcanism in India. However, the specific mechanisms of the extinction event and the extent of its effects on dinosaurs are still areas of ongoing research. Alongside | dinosaurs, many other groups of |
animals became extinct: pterosaurs, marine reptiles such as mosasaurs and plesiosaurs, several groups of mammals, ammonites( nautilus- like mollusks), rudists( reef- building bivalves), and various groups of marine plankton. In all, approximately 47% of genera and 76% of species on Earth became extinct during the K- Pg extinction event. The relatively large size of most dinosaurs and the low diversity of small- bodied dinosaur species at the end of the Cretaceous may have contributed to their extinction; the extinction of the bird lineages that did not survive may also have been caused by a dependence on forest habitats or a lack of adaptations to eating seeds for survival. Pre- extinction diversity. Just before the K- Pg extinction event, the number of non- avian dinosaur species that existed globally has been estimated at between 628 and 1078. It remains uncertain whether the diversity of dinosaurs was in gradual decline before the K- Pg extinction event, or whether dinosaurs were actually thriving prior to the extinction. Rock formations from the Maastrichtian epoch, which directly preceded the extinction, have been found to have lower diversity than the preceding Campanian epoch, which led to the prevailing view of a long- term decline in diversity. However, these comparisons did not account either for varying preservation potential between rock units or for different extents of exploration and excavation. In 1984, Dale Russell carried out an analysis to account for these biases, and found no evidence of a decline; another analysis by David Fastovsky and colleagues in 2004 even showed that dinosaur diversity continually increased until the extinction, but this analysis has been rebutted. Since then, different approaches based on statistics and mathematical models have variously supported either a sudden extinction or a gradual decline. End- Cretaceous trends in diversity may have varied between dinosaur lineages: it has been suggested that sauropods were not in decline, while ornithischians and theropods were in decline. Impact event. The bolide impact hypothesis, first brought to wide attention in 1980 by Walter Alvarez, Luis Alvarez, and colleagues, attributes the K- Pg extinction event to a bolide( extraterrestrial projectile) impact. Alvarez and colleagues proposed that a sudden increase in iridium levels, recorded around the world in rock deposits at the Cretaceous– Paleogene boundary, was direct evidence of the impact. Shocked quartz, indicative of a strong shockwave emanating from an impact, was also found worldwide. The actual impact site remained elusive until a crater measuring wide was discovered in the Yucatán Peninsula of southeastern Mexico, and was publicized in a 1991 paper by Alan Hildebrand and colleagues. Now, the bulk of the evidence suggests that a bolide wide impacted the Yucatán Peninsula 66 million years ago, forming this crater and creating a" kill mechanism" that triggered the extinction event. Within hours, the Chicxulub impact would have created immediate effects such as earthquakes, tsunamis, and a global firestorm that likely killed unsheltered animals and started wildfires. However, it would also have had longer- term consequences for the environment. Within days, sulphate aerosols released from rocks at the impact site would have contributed to acid rain and | ocean acidification. Soot aerosols are |
thought to have spread around the world over the ensuing months and years; they would have cooled the surface of the Earth by reflecting thermal radiation, and greatly slowed photosynthesis by blocking out sunlight, thus creating an impact winter.( This role was ascribed to sulphate aerosols until experiments demonstrated otherwise.) The cessation of photosynthesis would have led to the collapse of food webs depending on leafy plants, which included all dinosaurs save for grain- eating birds. Deccan Traps. At the time of the K- Pg extinction, the Deccan Traps flood basalts of India were actively erupting. The eruptions can be separated into three phases around the K- Pg boundary, two prior to the boundary and one after. The second phase, which occurred very close to the boundary, would have extruded 70 to 80% of the volume of these eruptions in intermittent pulses that occurred around 100, 000 years apart. Greenhouse gases such as carbon dioxide and sulphur dioxide would have been released by this volcanic activity, resulting in climate change through temperature perturbations of roughly but possibly as high as. Like the Chicxulub impact, the eruptions may also have released sulphate aerosols, which would have caused acid rain and global cooling. However, due to large error margins in the dating of the eruptions, the role of the Deccan Traps in the K- Pg extinction remains unclear. Before 2000, arguments that the Deccan Traps eruptions— as opposed to the Chicxulub impact— caused the extinction were usually linked to the view that the extinction was gradual. Prior to the discovery of the Chicxulub crater, the Deccan Traps were used to explain the global iridium layer; even after the crater' s discovery, the impact was still thought to only have had a regional, not global, effect on the extinction event. In response, Luis Alvarez rejected volcanic activity as an explanation for the iridium layer and the extinction as a whole. Since then, however, most researchers have adopted a more moderate position, which identifies the Chicxulub impact as the primary progenitor of the extinction while also recognizing that the Deccan Traps may also have played a role. Walter Alvarez himself has acknowledged that the Deccan Traps and other ecological factors may have contributed to the extinctions in addition to the Chicxulub impact. Some estimates have placed the start of the second phase in the Deccan Traps eruptions within 50, 000 years after the Chicxulub impact. Combined with mathematical modelling of the seismic waves that would have been generated by the impact, this has led to the suggestion that the Chicxulub impact may have triggered these eruptions by increasing the permeability of the mantle plume underlying the Deccan Traps. Whether the Deccan Traps were a major cause of the extinction, on par with the Chicxulub impact, remains uncertain. Proponents consider the climatic impact of the sulphur dioxide released to have been on par with the Chicxulub impact, and also note the role of flood basalt volcanism in other mass extinctions like the Permian- Triassic extinction event. They consider the Chicxulub impact to have worsened the ongoing climate | change caused by the eruptions. |
Meanwhile, detractors point out the sudden nature of the extinction and that other pulses in Deccan Traps activity of comparable magnitude did not appear to have caused extinctions. They also contend that the causes of different mass extinctions should be assessed separately. In 2020, Alfio Chiarenza and colleagues suggested that the Deccan Traps may even have had the opposite effect: they suggested that the long- term warming caused by its carbon dioxide emissions may have dampened the impact winter from the Chicxulub impact. Possible Paleocene survivors. Non- avian dinosaur remains have occasionally been found above the K- Pg boundary. In 2000, Spencer Lucas and colleagues reported the discovery of a single hadrosaur right femur in the San Juan Basin of New Mexico, and described it as evidence of Paleocene dinosaurs. The rock unit in which the bone was discovered has been dated to the early Paleocene epoch, approximately 64. 8 million years ago. If the bone was not re- deposited by weathering action, it would provide evidence that some dinosaur populations may have survived at least half a million years into the Cenozoic. Other evidence includes the presence of dinosaur remains in the Hell Creek Formation up to above the Cretaceous– Paleogene boundary, representing 40, 000 years of elapsed time. This has been used to support the view that the K- Pg extinction was gradual. However, these supposed Paleocene dinosaurs are considered by many other researchers to be reworked, that is, washed out of their original locations and then re- buried in younger sediments. The age estimates have also been considered unreliable. Cultural depictions. By human standards, dinosaurs were creatures of fantastic appearance and often enormous size. As such, they have captured the popular imagination and become an enduring part of human culture. The entry of the word" dinosaur" into the common vernacular reflects the animals' cultural importance: in English," dinosaur" is commonly used to describe anything that is impractically large, obsolete, or bound for extinction. Public enthusiasm for dinosaurs first developed in Victorian England, where in 1854, three decades after the first scientific descriptions of dinosaur remains, a menagerie of lifelike dinosaur sculptures was unveiled in London' s Crystal Palace Park. The Crystal Palace dinosaurs proved so popular that a strong market in smaller replicas soon developed. In subsequent decades, dinosaur exhibits opened at parks and museums around the world, ensuring that successive generations would be introduced to the animals in an immersive and exciting way. The enduring popularity of dinosaurs, in its turn, has resulted in significant public funding for dinosaur science, and has frequently spurred new discoveries. In the United States, for example, the competition between museums for public attention led directly to the BoneWarsofthe1880sand1890s, during which a pair of feuding paleontologists made enormous scientific contributions. The popular preoccupation with dinosaurs has ensured their appearance in literature, film, and other media. Beginning in 1852 with a passing mention in Charles Dickens" Bleak House", dinosaurs have been featured in large numbers of fictional works. Jules Verne' s 1864 novel" Journey to the Center of the Earth", Sir Arthur Conan Doyle' | s 1912 book" The Lost |
World", the 1914 animated film Gertie the Dinosaur( featuring the first animated dinosaur), the iconic 1933 film" King Kong", the 1954" Godzilla" and its many sequels, the best- selling 1990 novel" Jurassic Park" by Michael Crichton and its 1993 film adaptation are just a few notable examples of dinosaur appearances in fiction. Authors of general- interest non- fiction works about dinosaurs, including some prominent paleontologists, have often sought to use the animals as a way to educate readers about science in general. Dinosaurs are ubiquitous in advertising; numerous companies have referenced dinosaurs in printed or televised advertisements, either in order to sell their own products or in order to characterize their rivals as slow- moving, dim- witted, or obsolete. Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted by a magnetic field. Diamagnetism is a quantum mechanical effect that occurs in all materials; when it is the only contribution to the magnetism, the material is called diamagnetic. In paramagnetic and ferromagnetic substances, the weak diamagnetic force is overcome by the attractive force of magnetic dipoles in the material. The magnetic permeability of diamagnetic materials is less than the permeability of vacuum," μ" 0. In most materials, diamagnetism is a weak effect which can be detected only by sensitive laboratory instruments, but a superconductor acts as a strong diamagnet because it repels a magnetic field entirely from its interior. Diamagnetism was first discovered when Anton Brugmans observed in 1778 that bismuth was repelled by magnetic fields. In 1845, Michael Faraday demonstrated that it was a property of matter and concluded that every material responded( in either a diamagnetic or paramagnetic way) to an applied magnetic field. On a suggestion by William Whewell, Faraday first referred to the phenomenon as" diamagnetic"( the prefix" dia-" meaning" through" or" across"), then later changed it to" diamagnetism". A simple rule of thumb is used in chemistry to determine whether a particle( atom, ion, or molecule) is paramagnetic or diamagnetic: If all electrons in the particle are paired, then the substance made of this particle is diamagnetic; If it has unpaired electrons, then the substance is paramagnetic. Materials. Diamagnetism is a property of all materials, and always makes a weak contribution to the material' s response to a magnetic field. However, other forms of magnetism( such as ferromagnetism or paramagnetism) are so much stronger that, when multiple different forms of magnetism are present in a material, the diamagnetic contribution is usually negligible. Substances where the diamagnetic behaviour is the strongest effect are termed diamagnetic materials, or diamagnets. Diamagnetic materials are those that some people generally think of as" non- magnetic", and include water, wood, most organic compounds such as petroleum and some plastics, and many metals including copper, particularly the heavy ones with many core electrons, such as mercury, gold and bismuth. The magnetic susceptibility values of various molecular fragments are called Pascal' s constants. Diamagnetic materials, like water, or water- based | materials, have a relative magnetic |
permeability that is less than or equal to 1, and therefore a magnetic susceptibility less than or equal to 0, since susceptibility is defined as. This means that diamagnetic materials are repelled by magnetic fields. However, since diamagnetism is such a weak property, its effects are not observable in everyday life. For example, the magnetic susceptibility of diamagnets such as water is. The most strongly diamagnetic material is bismuth,, although pyrolytic carbon may have a susceptibility of in one plane. Nevertheless, these values are orders of magnitude smaller than the magnetism exhibited by paramagnets and ferromagnets. Because" χ" v is derived from the ratio of the internal magnetic field to the applied field, it is a dimensionless value. In rare cases, the diamagnetic contribution can be stronger than paramagnetic contribution. This is the case for gold, which has a magnetic susceptibility less than 0( and is thus by definition a diamagnetic material), but when measured carefully with X- ray magnetic circular dichroism, has an extremely weak paramagnetic contribution that is overcome by a stronger diamagnetic contribution. Superconductors. Superconductors may be considered perfect diamagnets(), because they expel all magnetic fields( except in a thin surface layer) due to the Meissner effect. Demonstrations. Curving water surfaces. If a powerful magnet( such as a supermagnet) is covered with a layer of water( that is thin compared to the diameter of the magnet) then the field of the magnet significantly repels the water. This causes a slight dimple in the water' s surface that may be seen by a reflection in its surface. Levitation. Diamagnets may be levitated in stable equilibrium in a magnetic field, with no power consumption. Earnshaw' s theorem seems to preclude the possibility of static magnetic levitation. However, Earnshaw' s theorem applies only to objects with positive susceptibilities, such as ferromagnets( which have a permanent positive moment) and paramagnets( which induce a positive moment). These are attracted to field maxima, which do not exist in free space. Diamagnets( which induce a negative moment) are attracted to field minima, and there can be a field minimum in free space. A thin slice of pyrolytic graphite, which is an unusually strongly diamagnetic material, can be stably floated in a magnetic field, such as that from rare earth permanent magnets. This can be done with all components at room temperature, making a visually effective and relatively convenient demonstration of diamagnetism. The Radboud University Nijmegen, the Netherlands, has conducted experiments where water and other substances were successfully levitated. Most spectacularly, a live frog( see figure) was levitated. In September 2009, NASA' s Jet Propulsion Laboratory( JPL) in Pasadena, California announced it had successfully levitated mice using a superconducting magnet, an important step forward since mice are closer biologically to humans than frogs. JPL said it hopes to perform experiments regarding the effects of microgravity on bone and muscle mass. Recent experiments studying the growth of protein crystals have led to a technique using powerful magnets to allow growth in ways that counteract Earth' s gravity. A simple homemade device for demonstration can be constructed out of | bismuth plates and a few |
permanent magnets that levitate a permanent magnet. Theory. The electrons in a material generally settle in orbitals, with effectively zero resistance and act like current loops. Thus it might be imagined that diamagnetism effects in general would be common, since any applied magnetic field would generate currents in these loops that would oppose the change, in a similar way to superconductors, which are essentially perfect diamagnets. However, since the electrons are rigidly held in orbitals by the charge of the protons and are further constrained by the Pauli exclusion principle, many materials exhibit diamagnetism, but typically respond very little to the applied field. The Bohr– Van Leeuwen theorem proves that there cannot be any diamagnetism or paramagnetism in a purely classical system. However, the classical theory of Langevin for diamagnetism gives the same prediction as the quantum theory. The classical theory is given below. Langevin diamagnetism. Paul Langevin' s theory of diamagnetism( 1905) applies to materials containing atoms with closed shells( see dielectrics). A field with intensity, applied to an electron with charge and mass, gives rise to Larmor precession with frequency. The number of revolutions per unit time is, so the current for an atom with electrons is( in SI units) The magnetic moment of a current loop is equal to the current times the area of the loop. Suppose the field is aligned with the axis.Theaverageloopareacanbegivenasformula_2,whereformula_3 is the mean square distance of the electrons perpendicular to the axis. The magnetic moment is thereforeIf the distribution of charge is spherically symmetric, we can suppose that the distribution of coordinates are independent and identically distributed.Thenformula_5,whereformula_6 is the mean square distance of the electrons from the nucleus. Therefore,formula_7.Ifformula_8 is the number of atoms per unit volume, the volume diamagnetic susceptibility in SI units isIn atoms, Langevin susceptibility is of the same order of magnitude as Van Vleck paramagnetic susceptibility. In metals. The Langevin theory is not the full picture for metals because there are also non- localized electrons. The theory that describes diamagnetism in a free electron gas is called Landau diamagnetism, named after Lev Landau, and instead considers the weak counteracting field that forms when the electrons' trajectories are curved due to the Lorentz force. Landau diamagnetism, however, should be contrasted with Pauli paramagnetism, an effect associated with the polarization of delocalized electrons' spins.Forthebulkcaseofa3D system and low magnetic fields, the( volume) diamagnetic susceptibility can be calculated using Landau quantization,whichinSIunitsiswhereformula_11 is the Fermi energy.Thisisequivalenttoformula_12,exactlyformula_13 times Pauli paramagnetic susceptibility,whereformula_14 istheBohrmagnetonandformula_15 is the density of states( number of states per energy per volume). This formula takes into account the spin degeneracy of the carriers(spin½ electrons). In doped semiconductors the ratio between Landau and Pauli susceptibilities may change due to the effective mass of the charge carriers differing from the electron mass in vacuum, increasing the diamagnetic contribution. The formula presented here only applies for the bulk; in confined systems like quantum dots, the description is altered due to quantum confinement. Additionally, for strong magnetic fields, the susceptibility of delocalized electrons oscillates as a function of the field strength, a phenomenon known as the De Haas– | Van Alphen effect, also first |
described theoretically by Landau. Duke of Marlborough() is a title in the Peerage of England. It was created by Queen Anne in 1702 for John Churchill,1st Earl of Marlborough( 1650– 1722), the noted military leader. In historical texts,unqualifieduseofthetitletypicallyreferstothe1st Duke. The name of the dukedom refers to Marlborough in Wiltshire.TheearldomofMarlboroughwasheldbythefamilyofLeyfromitscreation1626untilitsextinctionwiththedeathofthe4th earl in 1679. The title was recreated 10 years later for John Churchill( in 1689). History of the dukedom. Churchill had been made" Lord Churchill of Eyemouth"( 1682) in the Peerage of Scotland, and" Baron Churchill" of Sandridge( 1685) and" Earl of Marlborough"( 1689) in the Peerage of England. Shortly after her accession to the throne in 1702, Queen Anne made Churchill the first" Duke of Marlborough" and also granted him the subsidiary title" Marquess of Blandford". In 1678, Churchill married Sarah Jennings( 1660– 1744), a courtier and influential favourite of the queen. They had seven children, of whom four daughters married into some of the most important families in Great Britain; one daughter and one son died in infancy. He was pre- deceased by his son, John Churchill, Marquess of Blandford, in 1703; so, to prevent the extinction of the titles, a special Act of Parliament was passed.Whenthe1st Duke of Marlborough died in 1722 his title as" Lord Churchill of Eyemouth" in the Peerage of Scotland became extinct and the Marlborough titles passed, according to the Act, to his eldest daughter Henrietta( 1681– 1733),the2nd Duchess of Marlborough.Shewasmarriedtothe2nd Earl of Godolphin and had a son who predeceased her. When Henrietta died in 1733, the Marlborough titles passed to her nephew Charles Spencer( 1706– 1758), the third son of her late sister Anne( 1683– 1716),whohadmarriedthe3rd Earl of Sunderland in 1699. After his older brother' s death in 1729, Charles Spencer had already inherited the Spencer family estates and the titles of" Earl of Sunderland"( 1643) and" Baron Spencer" of Wormleighton( 1603), all in the Peerage of England. Upon his maternal aunt Henrietta' s death in 1733, Charles SpencersucceededtotheMarlboroughfamilyestatesandtitlesandbecamethe3rd Duke. When he died in 1758, his titles passed to his eldest son George( 1739– 1817), who was succeeded by his eldest son George,the5th Duke( 1766– 1840). In 1815, Francis Spencer(theyoungersonofthe4th Duke) was created" Baron Churchill" in the Peerage of the United Kingdom. In 1902, his grandson,the3rd Baron Churchill, was created Viscount Churchill. In 1817,the5th Duke obtained permission to assume and bear the surname of Churchill in addition to his surname of Spencer, to perpetuate the name of his illustrious great- great- grandfather. At the same time he received Royal Licence to quarter the coat of arms of Churchill with his paternal arms of Spencer. The modern Dukes thus originally bore the surname" Spencer": the double- barrelled surname of" Spencer- Churchill" as used since 1817 remains in the family, although many members have preferred to style themselves simply as" Churchill".The7th Duke was the paternal grandfather of the British Prime Minister Sir Winston Churchill, born at Blenheim Palace on 30 November 1874.The11th Duke, John Spencer- Churchill died in 2014, having assumed the title in 1972.The12th and present Duke is Charles James Spencer- Churchill. Family seat. The family | seat is Blenheim Palace in |
Woodstock, Oxfordshire. After his leadership in the victory against the French in the Battle of Blenheim on 13 August 1704,the1st Duke was honoured by Queen Anne granting him the royal manor of Woodstock, and building him a house at her expense to be called Blenheim. Construction started in 1705 and the house was completed in 1722,theyearofthe1st Duke' s death. Blenheim Palace has since remained in the Churchill and Spencer- Churchill family.Withtheexceptionofthe10th Duke and his first wife, the Dukes and Duchesses of Marlborough are buried in Blenheim Palace' s chapel. Most other members of the Spencer- Churchill family are interred in St. Martin' s parish churchyard at Bladon, a short distance from the palace. Succession to the title. The dukedom can theoretically pass through a female line. However, unlike the remainder to heirs general found in most other peerages that allow male- preference primogeniture, the grant does not allow for abeyance and follows a more restrictive Semi- Salic formula designed to keep succession wherever possible in the male line. The succession is as follows: Succession to the title under the first and second contingencies have lapsed;holdersofthetitlefromthe3rd Duke trace their status from the third contingency. It is now very unlikely that the dukedom will be passed to a woman or through a woman, since all the male-linedescendantsofthe1st Duke' s second daughter Anne Spencer, Countess of Sunderland— including the lines of the Viscounts Churchill and Barons Churchill of Wychwood and of the Earl Spencer and of the entire Spencer- Churchill and Spencer family— would have to become extinct. If that were to happen, the Churchill titles would pass to the Earl of Jersey( and merge with the earldom as long as it is extant), the heir-maleofthe1st Duke' s granddaughter Anne Villiers( born Egerton), Countess of Jersey, daughter of Elizabeth Egerton, Duchess of Bridgewater, the third daughter of the first Duke. The next heir would be the Duke of Buccleuch, the heir-maleofthe1st Duke' s great- granddaughter Elizabeth Montagu, Duchess of Buccleuch, the daughter of Mary Montagu, Duchess of Montagu( 1766 creation),thedaughterofthe1st Duke' s youngest daughter Mary, Duchess of Montagu( 1705 creation). The fourth surviving line is represented by the Earl of Chichester and his family, the heir-maleofthe1st Duke' s most senior great- great- granddaughter Mary Henrietta Osborne, Countess of Chichester, daughter of Francis Osborne,5th Duke of Leeds, only child of Mary Godolphin, Duchess of Leeds,daughterofthe1st Duke' s eldest daughter Henrietta Godolphin,2nd Duchess of Marlborough, by her husband Francis Godolphin,2nd Earl of Godolphin. Other titles of the Dukes. Subsidiary titles. The Duke holds subsidiary titles:" Marquess of Blandford"( created in 1702 for John Churchill)," Earl of Sunderland"( created in 1643 for the Spencer family)," Earl of Marlborough"( created in 1689 for John Churchill)," Baron Spencer" of Wormleighton( created in 1603 for the Spencer family), and" Baron Churchill" of Sandridge( created in 1685 for John Churchill), all in the Peerage of England. The title" Marquess of Blandford" is used as the courtesy title for the Duke' s eldest son and heir. The Duke' s eldest son' s eldest son can use the courtesy title" Earl of Sunderland", and | the duke' s eldest son' |
s eldest son' s eldest son( not necessarily the eldest great- grandson) the title" Lord Spencer of Wormleighton"( not to be confused with Earl Spencer). The title of" Earl of Marlborough", created for John Churchill in 1689, had previously been created for James Ley, in 1626, becoming extinct in 1679. Foreign titles.The1st Duke was honoured with land and titles in the Holy Roman Empire: Emperor Leopold I created him a Prince in 1704, and in 1705, his successor Emperor Joseph I gave him the principality of Mindelheim( once the lordship of the noted soldier Georg von Frundsberg). He was obliged to surrender Mindelheim in 1714 by the Treaty of Utrecht, which returned it to Bavaria. He tried to obtain Nellenburg in Austria in exchange, which at that time was only a county(' Landgrafschaft'), but this failed, partially because Austrian law did not allow for Nellenburg to be converted into a sovereign principality.The1st Duke' s princely title of Mindelheim became extinct either on the return of the land to Bavaria or on his death, as the Empire operated Salic Law, which prevented female succession. Coats of arms. Original arms of the Churchill family. The original arms of Sir Winston Churchill( 1620– 1688),fatherofthe1st Duke of Marlborough, were simple and in use by his own father in 1619. The shield was Sable a lion rampant Argent, debruised by a bendlet Gules. The addition of a canton of Saint George( see below) rendered the distinguishing mark of the bendlet unnecessary. The Churchill crest is blazoned as a lion couchant guardant Argent, supporting with its dexter forepaw a banner Gules, charged with a dexter hand appaumée of the first, staff Or. In recognition of Sir Winston' s services to King Charles I as Captain of the Horse, and his loyalty to King Charles II as a Member of Parliament, he was awarded an augmentation of honour to his arms around 1662. This rare mark of royal favour took the form of a canton of Saint George. At the same time, he was authorised to omit the bendlet, which had served the purpose of distinguishing this branch of the Churchill family from others which bore an undifferenced lion.Armsofthe1st Duke of Marlborough. Sir Winston' s shield and crest were inherited by his son John Churchill,1st Duke of Marlborough. Minor modifications reflected the bearer' s social rise: the helm was now shown in profile and had a closed grille to signify the bearer' s rank as a peer, and there were now supporters placed on either side of the shield. They were the mythical Griffin( part lion, part eagle) and Wyvern( a dragon without hind legs). The supporters were derived from the arms of thefamilyofthe1st Duke' s mother, Drake of Ash( Argent, a wyvern gules; these arms can be seen on the monument in Musbury Church to Sir Bernard Drake, d. 1586). The motto was" Fiel pero desdichado"( Spanish for" Faithful but unfortunate").The1st Duke was also entitled to a coronet indicating his rank. When the1st Duke was made a Prince of the Holy Roman Empire in 1705, two unusual features | were added: the Imperial Eagle |
and a Princely Coronet. His estates in Germany, such as Mindelheim, were represented in his arms by additional quarterings. Arms of the Spencer- Churchill family. In 1817,the5th Duke received Royal Licence to place the quarter of Churchill ahead of his paternal arms of Spencer. The shield of the Spencer family arms is: quarterly Argent and Gules, in the second and third quarters a fret Or, over all on a bend Sable three escallops of the first. The Spencer crest is: out of a ducal coronet Or, a griffin' s head between two wings expanded Argent, gorged with a collar gemel and armed Gules. Paul Courtenay observes that" It would be normal in these circumstances for the paternal arms( Spencer) to take precedence over the maternal( Churchill), but because the Marlborough dukedom was senior to the Sunderland earldom, the procedure was reversed in this case." Also in 1817, a further augmentation of honour was added to his armorial achievement. This incorporated the bearings from the standard of the Manor of Woodstock and was borne on an escutcheon, displayed over all in the centre chief point, as follows: Argent a cross of Saint George surmounted by an inescutcheon Azure, charged with three fleurs- de- lys Or, two over one. This inescutcheon represents the royal arms of France. These quartered arms, incorporating the two augmentations of honour, have been the arms of all subsequent Dukes of Marlborough. Motto. The motto" Fiel pero desdichado" is Spanish for" Faithful though Joyless"." Desdichado" means without happiness or without joy, alluding to the first Duke' s father, Winston, who was a royalist and faithful supporter of the king during the English Civil War but was not compensated for his losses after the restoration. Charles II knighted Winston Churchill and other Civil War royalists but did not compensate them for their wartime losses, thereby inducing Winston to adopt the motto. It is unusual for the motto of an Englishman of the era to be in Spanish rather than Latin, and it is not known why this is the case. List of title holders. Earls of Marlborough, first creation( 1626– 1679). The earldom of Marlborough was held by the family of Ley from 1626 to 1679. James Ley,the1st Earl( c. 1550– 1629), was lord chief justice of the King’ s Bench in Ireland and then in England; he was an English member of parliament and was lord high treasurer from 1624 to 1628. In 1624 he was created Baron Ley and in 1626 Earl of Marlborough.The3rd earl was his grandson James( 1618– 1665), a naval officer who was killed in action with the Dutch. James was succeeded by his uncle William,ayoungersonofthe1st earl, on whose death in 1679 the earldom became extinct. Dukes of Marlborough( 1702). The heir apparent to the dukedom is George John Godolphin Spencer- Churchill, Marquess of Blandford( b. 1992),eldestsonofthe12th Duke. Family tree.& lt; section begin= FamilyTree/& gt;& lt; section end=" FamilyTree"/& gt; A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. It was designed inthe1820s, and was first created by Charles Babbage. The name, | the difference engine, is derived |
from the method of divided differences, a way to interpolate or tabulate functions by using a small set of polynomial co- efficients. Some of the most common mathematical functions used in engineering, science and navigation, were, and still are computable with the use of the difference engine' s capability of computing logarithmic and trigonometric functions, which can be approximated by polynomials, so a difference engine can compute many useful tables of numbers. History.ThenotionofamechanicalcalculatorformathematicalfunctionscanbetracedbacktotheAntikytheramechanismofthe2nd century BC,whileearlymodernexamplesareattributedtoPascalandLeibnizinthe17th century. In 1784 J. H. Müller, an engineer in the Hessian army, devised and built an adding machine and described the basic principles of a difference machine in a book published in 1786( the first written reference to a difference machine is dated to 1784), but he was unable to obtain funding to progress with the idea. Charles Babbage' s difference engines. Charles Babbage began to construct a small difference engine in c. 1819 and had completed it by 1822( Difference Engine 0). He announced his invention on 14 June 1822, in a paper to the Royal Astronomical Society, entitled" Note on the application of machinery to the computation of astronomical and mathematical tables". This machine used the decimal number system and was powered by cranking a handle. The British government was interested, since producing tables was time- consuming and expensive and they hoped the difference engine would make the task more economical. In 1823, the British government gave Babbage£ 1700 to start work on the project. Although Babbage' s design was feasible, the metalworking techniques of the era could not economically make parts in the precision and quantity required. Thus the implementation proved to be much more expensive and doubtful of success than the government' s initial estimate. In 1832, Babbage and Joseph Clement produced a small working model( one- seventh of the calculating section of Difference Engine No. 1, which was intended to operate on 20- digit numbers and sixth- order differences) which operated on 6- digit numbers and second- order differences. Lady Byron described seeing the working prototype in 1833:" We both went to see the thinking machine( or so it seems) last Monday. It raised several Nos.tothe2ndand3rd powers, and extracted the root of a Quadratic equation." Work on the larger engine was suspended in 1833. By the time the government abandoned the project in 1842, Babbage had received and spent over£ 17, 000 on development, which still fell short of achieving a working engine. The government valued only the machine' s output( economically produced tables), not the development( at unpredictable cost) of the machine itself. Babbage did not, or was unwilling to, recognize that predicament. Meanwhile, Babbage' s attention had moved on to developing an analytical engine, further undermining the government' s confidence in the eventual success of the difference engine. By improving the concept as an analytical engine, Babbage had made the difference engine concept obsolete, and the project to implement it an utter failure in the view of the government. The incomplete Difference Engine No. 1 was put on display to the public at the 1862 International Exhibition in South Kensington, | London. Babbage went on to |
design his much more general analytical engine, but later produced an improved" Difference Engine No. 2" design( 31- digit numbers and seventh- order differences), between 1846 and 1849. Babbage was able to take advantage of ideas developed for the analytical engine to make the new difference engine calculate more quickly while using fewer parts. Scheutzian calculation engine. Inspired by Babbage' s difference engine in 1834, Per Georg Scheutz built several experimental models. In 1837 his son Edward proposed to construct a working model in metal, and in 1840 finished the calculating part, capable of calculating series with 5- digit numbers and first- order differences, which was later extended to third- order( 1842). In 1843, after adding the printing part, the model was completed. In 1851, funded by the government, construction of the larger and improved( 15- digit numbers and fourth- order differences) machine began, and finished in 1853. The machine was demonstrated at the World' s Fair in Paris, 1855 and then sold in 1856 to the Dudley Observatory in Albany, New York. Delivered in 1857, it was the first printing calculator sold. In 1857 the British government ordered the next Scheutz' s difference machine, which was built in 1859. It had the same basic construction as the previous one, weighing about. Others. Martin Wiberg improved Scheutz' s construction( c. 1859, his machine has the same capacity as Scheutz' s- 15- digit and fourth- order) but used his device only for producing and publishing printed tables( interest tables in 1860, and logarithmic tables in 1875). Alfred Deacon of London in c. 1862 produced a small difference engine( 20- digit numbers and third- order differences). American George B. Grant started working on his calculating machine in 1869, unaware of the works of Babbage and Scheutz( Schentz). One year later( 1870) he learned about difference engines and proceed to design one himself, describing his construction in 1871. In 1874 the Boston Thursday Club raised a subscription for the construction of a large- scale model, which was built in 1876. It could be expanded to enhance precision and weighed about. Christel Hamann built one machine( 16- digit numbers and second- order differences) in 1909 for the" Tables of Bauschinger and Peters"(" Logarithmic- Trigonometrical Tables with eight decimal places"), which was first published in Leipzig in 1910. It weighed about. Burroughs Corporation in about 1912 built a machine for the Nautical Almanac Office which was used as a difference engine of second- order. It was later replaced in 1929 by a Burroughs Class 11( 13- digit numbers and second- order differences, or 11- digit numbers and[ at least up to] fifth- order differences). Alexander John Thompson about 1927 built" integrating and differencing machine"( 13- digit numbers and fifth- order differences) for his table of logarithms" Logarithmetica britannica". This machine was composed of four modified Triumphator calculators. Leslie Comrie in 1928 described how to use the Brunsviga- Dupla calculating machine as a difference engine of second- order( 15- digit numbers). He also noted in 1931 that National Accounting Machine Class 3000 could be used as a difference | engine of sixth- order. Construction |
of two working No. 2 difference engines.Duringthe1980s, Allan G. Bromley, an associate professor at the University of Sydney, Australia, studied Babbage' s original drawings for the Difference and Analytical Engines at the Science Museum library in London. This work led the Science Museum to construct a working calculating section of difference engine No. 2 from 1985 to 1991, under Doron Swade, the then Curator of Computing.Thiswastocelebratethe200th anniversary of Babbage' s birth in 1991. In 2002, the printer which Babbage originally designed for the difference engine was also completed. The conversion of the original design drawings into drawings suitable for engineering manufacturers' use revealed some minor errors in Babbage' s design( possibly introduced as a protection in case the plans were stolen), which had to be corrected. Once completed, both the engine and its printer worked flawlessly, and still do.Thedifferenceengineandprinterwereconstructedtotolerancesachievablewith19th- century technology, resolving a long- standing debate as to whether Babbage' s design would have worked.( One of the reasons formerly advanced for the non- completion of Babbage' s engines had been that engineering methods were insufficiently developed in the late Georgian era.) The printer' s primary purpose is to produce stereotype plates for use in printing presses, which it does by pressing type into soft plaster to create a flong. Babbage intended that the Engine' s results be conveyed directly to mass printing, having recognized that many errors in previous tables were not the result of human calculating mistakes but from error in the manual typesetting process. The printer' s paper output is mainly a means of checking the engine' s performance. In addition to funding the construction of the output mechanism for the Science Museum' s difference engine, Nathan Myhrvold commissioned the construction of a second complete Difference Engine No. 2, which was on exhibit at the Computer History Museum in Mountain View, California from 10 May 2008 until 31 January 2016. It has since been transferred to Intellectual Ventures in Seattle where it is on display just outside the main lobby. Operation. The difference engine consists of a number of columns, numbered from 1 to N. The machine is able to store one decimal number in each column. The machine can only add the value of a column" n"+ 1 to column" n" to produce the new value of" n". Column" N" can only store a constant, column 1 displays( and possibly prints) the value of the calculation on the current iteration. The engine is programmed by setting initial values to the columns. Column 1 is set to the value of the polynomial at the start of computation. Column 2 is set to a value derived from the first and higher derivatives of the polynomial at the same value of X. Each of the columns from 3 to" N" is set toavaluederivedfromtheformula_1 first and higher derivatives of the polynomial. Timing. In the Babbage design, one iteration( i. e., one full set of addition and carry operations) happens for each rotation of the main shaft. Odd and even columns alternately perform an addition in one cycle. The sequence of operations forcolumnformula_2 | is thus: Steps 1, 2, |
3, 4 occur for every odd column, while steps 3, 4, 1, 2 occur for every even column. While Babbage' s original design placed the crank directly on the main shaft, it was later realized that the force required to crank the machine would have been too great for a human to handle comfortably. Therefore, the two models that were built incorporate a 4: 1 reduction gear at the crank, and four revolutions of the crank are required to perform one full cycle. Steps. Each iteration creates a new result, and is accomplished in four steps corresponding to four complete turns of the handle shown at the far right in the picture below. The four steps are: Subtraction. The engine represents negative numbers as ten' s complements. Subtraction amounts to addition of a negative number. This works in the same manner that modern computers perform subtraction, known as two' s complement. Method of differences. The principle of a difference engine is Newton' s method of divided differences. If the initial value of a polynomial( and of its finite differences) is calculated by some means for some value of X, the difference engine can calculate any number of nearby values, using the method generally known as the method of finite differences. For example, consider the quadratic polynomialwith the goal of tabulating the values" p"( 0)," p"( 1)," p"( 2)," p"( 3)," p"( 4), and so forth. The table below is constructed as follows: the second column contains the values of the polynomial, the third column contains the differences of the two left neighbors in the second column, and the fourth column contains the differences of the two neighbors in the third column: The numbers in the third values- column are constant. In fact, by starting with any polynomial of degree" n", the column number" n"+ 1 will always be constant. This is the crucial fact behind the success of the method. This table was built from left to right, but it is possible to continue building it from right to left down a diagonal in order to compute more values. To calculate" p"( 4) use the values from the lowest diagonal. Start with the fourth column constant value of 4 and copy it down the column. Then continue the third column by adding 4 to 11 to get 15. Next continue the second column by taking its previous value, 22 and adding the 15 from the third column. Thus" p"( 5) is 22+ 15= 37. In order to compute" p"( 6), we iterate the same algorithm on the" p"( 5) values: take 4 from the fourth column, add that to the third column' s value 15 to get 19, then add that to the second column' s value 37 to get 56, which is" p"( 6). This process may be continued" ad infinitum". The values of the polynomial are produced without ever having to multiply. A difference engine only needs to be able to add. From one loop to the next, it needs to store 2 numbers— in this example( the last elements | in the first and second |
columns). To tabulate polynomials of degree" n", one needs sufficient storage to hold" n" numbers. Babbage' s difference engine No. 2, finally built in 1991,canhold8numbersof31decimaldigitseachandcanthustabulate7th degree polynomials to that precision. The best machines from Scheutz could store 4 numbers with 15 digits each. Initial values. The initial values of columns can be calculated by first manually calculating N consecutive values of the function and by backtracking, i. e. calculating the required differences.Colformula_6getsthevalueofthefunctionatthestartofcomputationformula_7.Colformula_8isthedifferencebetweenformula_9andformula_7... If the function to be calculated is a polynomial function, expressed asthe initial values can be calculated directly from the constant coefficients" a" 0," a" 1," a" 2,...," an" without calculating any data points. The initial values are thus: Use of derivatives. Many commonly used functions are analytic functions, which can be expressed as power series, for example as a Taylor series. The initial values can be calculated to any degree of accuracy; if done correctly the engine will give exact results for first N steps. After that, the engine will only give an approximation of the function. The Taylor series expresses the function as a sum obtained from its derivatives at one point. For many functions the higher derivatives are trivial to obtain; for instance,thesinefunctionat0hasvaluesof0orformula_19 for all derivatives. Setting 0 as the start of computation we get the simplified Maclaurin seriesThe same method of calculating the initial values from the coefficients can be used as for polynomial functions. The polynomial constant coefficients will now have the valueCurve fitting. The problem with the methods described above is that errors will accumulate and the series will tend to diverge from the true function. A solution which guarantees a constant maximum error is to use curve fitting. A minimum of" N" values are calculated evenly spaced along the range of the desired calculations. Using a curve fitting technique like Gaussian reduction an" N"−1th degree polynomial interpolation of the function is found. With the optimized polynomial, the initial values can be calculated as above. In Norse mythology, Draupnir( Old Norse:," the dripper") is a gold ring possessed by the god Odin with the ability to multiply itself: Every ninth night, eight new rings' drip' from Draupnir, each one of the same size and weight as the original. Draupnir was forged by the dwarven brothers Brokkr and Eitri( or Sindri). Brokkr and Eitri made this ring as one of a set of three gifts which included Mjöllnir and Gullinbursti. They made these gifts in accordance with a bet Loki made saying that Brokkr and Eitri could not make better gifts than the three made by the Sons of Ivaldi. In the end, Mjöllnir, Thor' s hammer, won the contest for Brokkr and Eitri. Loki used a loophole to get out of the wager for his head( the wager was for Loki' s head only, but he argued that, to remove his head, they would have to injure his neck, which was not in the bargain) and Brokkr punished him by sealing his lips shut with wire. The ring was placed by Odin on the funeral pyre of his son Baldr: Odin laid upon the | pyre the gold ring called |
Draupnir; this quality attended it: that every ninth night there fell from it eight gold rings of equal weight.( from the" Gylfaginning"). The ring was subsequently retrieved by Hermóðr. It was offered as a gift by Freyr' s servant Skírnir in the wooing of Gerðr, which is described in the poem" Skírnismál". In popular culture. Draupnir is represented as a card in the" Yu- Gi- Oh" Trading Card Game. It has an effect that mimics the multiplication ability of the mythological version. If it is destroyed by another card' s effect, you can add another" Nordic Relic" card to your hand. Draupnir also has a representation in the"" set" Kaldheim", which is based on Nordic mythology. The card Replicating Ring adds a night counter to itself each turn, and once eight counters are put on it, it makes eight Replicated Rings." DRAUPNIR" was revealed as the key to a website that Neal Caffrey and Mozzie used to view their stolen Nazi U- boat treasure in" Taking Account", the seventh episode of the third season of" White Collar". It also appeared in episode 11 of"" as a tool to seal Loki' s spirit. The Draupnir is never called by name but is simply known as Odin' s ring in the first three books of the" Witches of East End" novels. This ring allows the wearer to teleport to any place of the nine worlds, and a copy of equal power was once owned by Loki before it was destroyed by Freya. In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field' s source at each point. More technically, the divergence represents the volume density of the outward flux of a vector field from an infinitesimal volume around a given point. As an example, consider air as it is heated or cooled. The velocity of the air at each point defines a vector field. While air is heated in a region, it expands in all directions, and thus the velocity field points outward from that region. The divergence of the velocity field in that region would thus have a positive value. While the air is cooled and thus contracting, the divergence of the velocity has a negative value. Physical interpretation of divergence. In physical terms, the divergence of a vector field is the extent to which the vector field flux behaves like a source at a given point. It is a local measure of its" outgoingness"– the extent to which there are more of the field vectors exiting an infinitesimal region of space than entering it. A point at which the flux is outgoing has positive divergence, and is often called a" source" of the field. A point at which the flux is directed inward has negative divergence, and is often called a" sink" of the field. The greater the flux of field through a small surface enclosing a given point, the greater the value of divergence at that point. A point at which there is zero flux through | an enclosing surface has zero |
divergence. The divergence of a vector field is often illustrated using the example of the velocity field of a fluid, a liquid or gas. A moving gas has a velocity, a speed and direction, at each point which can be represented by a vector, so the velocity of the gas forms a vector field. If a gas is heated, it will expand. This will cause a net motion of gas particles outward in all directions. Any closed surface in the gas will enclose gas which is expanding, so there will be an outward flux of gas through the surface. So the velocity field will have positive divergence everywhere. Similarly, if the gas is cooled, it will contract. There will be more room for gas particles in any volume, so the external pressure of the fluid will cause a net flow of gas volume inward through any closed surface. Therefore the velocity field has negative divergence everywhere. In contrast, in a gas at a constant temperature and pressure, the net flux of gas out of any closed surface is zero. The gas may be moving, but the volume rate of gas flowing into any closed surface must equal the volume rate flowing out, so the" net" flux is zero. Thus the gas velocity has zero divergence everywhere. A field which has zero divergence everywhere is called solenoidal. If the gas is heated only at one point or small region, or a small tube is introduced which supplies a source of additional gas at one point, the gas there will expand, pushing fluid particles around it outward in all directions. This will cause an outward velocity field throughout the gas, centered on the heated point. Any closed surface enclosing the heated point will have a flux of gas particles passing out of it, so there is positive divergence at that point. However any closed surface" not" enclosing the point will have a constant density of gas inside, so just as many fluid particles are entering as leaving the volume, thus the net flux out of the volume is zero. Therefore the divergence at any other point is zero. Definition.[[ Image: Definition of divergence. svg| thumb| The divergence at a point is the limitoftheratioofthefluxformula_1 through the surface"( red arrows)"tothevolumeformula_2 for any sequence of closed regions enclosing that approaches zero volume:formula_3, where is the[[ metric tensor]]. The[[ determinant]] appears because it provides the appropriate invariant definition of the volume, given a set of vectors. Since the determinant is a scalar quantity which doesn' t depend on the indices, these can be suppressed,writingformula_4. The absolute value is taken in order to handle the general case where the determinant might be negative, such as in pseudo- Riemannian spaces. The reason for the square- root is a bit subtle: it effectively avoids double- counting as one goes from curved to Cartesian coordinates, and back. The volume( the determinant) can also be understood as the[[ Jacobian matrix and determinant| Jacobian]] of the transformation from Cartesian to curvilinear coordinates, which for givesSome conventions expect all local basis elements to be normalized | to unit length, as was |
done in the previous sections.Ifwewriteformula_5 for the normalized basis,andformula_6 for the components of with respect to it, we have thatusing one of the properties of the metric tensor.Bydottingbothsidesofthelastequalitywiththecontravariantelementformula_8,wecanconcludethatformula_9. After substituting, the formula becomes: See"" for further discussion. Properties. The following properties can all be derived from the ordinary differentiation rules of[[ calculus]]. Most importantly, the divergence is a[[ linear operator]], i. e., for all vector fields and and all[[ real number]] s and. There is a[[ product rule]] of the following type: if is a scalar- valued function and is a vector field, thenor in more suggestive notationAnother product rule for the[[ cross product]] of two vector fields and in three dimensions involves the[[ Curl( mathematics)| curl]] and reads as follows: The[[ Laplacian]] of a[[ scalar field]] is the divergence of the field' s[[ gradient]]: The divergence of the[[ Curl( mathematics)| curl]] of any vector field( in three dimensions) is equal to zero: If a vector field with zero divergence is defined on a ball in, then there exists some vector field on the ball with. For regions in more topologically complicated than this, the latter statement might be false( see[[ Poincaré lemma]]). The degree of" failure" of the truth of the statement, measured by the[[ homology( mathematics)| homology]] of the[[ chain complex]] serves as a nice quantification of the complicatedness of the underlying region. These are the beginnings and main motivations of[[ de Rham cohomology]]. Decomposition theorem. It can be shown that any stationary flux that is twice continuously differentiable in and vanishes sufficiently fast for can be decomposed uniquely into an" irrotational part" and a" source- free part". Moreover, these parts are explicitly determined by the respective" source densities"( see above) and" circulation densities"( see the article[[ Curl( mathematics)| Curl]]): For the irrotational part one haswithThe source- free part,, can be similarly written: one only has to replace the" scalar potential" by a" vector potential" and the terms by, and the source densityby the circulation density. This" decomposition theorem" is a by- product of the stationary case of[[ electrodynamics]]. It is a special case of the more general[[ Helmholtz decomposition]], which works in dimensions greater than three as well. In arbitrary dimensions. The divergence of a vector field can be defined in any number of dimensions. in a Euclidean coordinate system with coordinates, defineIn the case of one dimension, reduces to a regular function, and the divergence reduces to the derivative. For any, the divergence is a linear operator, and it satisfies the" product rule" for any scalar- valued function. Relation to the exterior derivative. One can express the divergence as a particular case of the[[ exterior derivative]], which takes a[[ 2- form]] to a 3- form in. Define the current two- form asIt measures the amount of" stuff" flowing through a surface per unit time in a" stuff fluid" of density moving with local velocity. Its exterior derivative isthengivenbywhereformula_26 is the[[ wedge product]]. Thus, the divergence of the vector field can be expressed as: Here the superscript is one of the two[[ musical isomorphism]] s, and is the[[ Hodge | star operator]]. When the divergence |
is written in this way,theoperatorformula_28 is referred to as the[[ codifferential]]. Working with the current two- form and the exterior derivative is usually easier than working with the vector field and divergence, because unlike the divergence, the exterior derivative commutes with a change of( curvilinear) coordinate system. In curvilinear coordinates. The appropriate expression is more complicated in[[ Curvilinear coordinates# Grad, curl, div, Laplacian| curvilinear coordinates]]. The divergence of a vector field extends naturally to any[[ differentiable manifold]] of dimension that has a[[ volume form]]( or[[ density on a manifold| density]]), e. g. a[[ Riemannian manifold| Riemannian]] or[[ Lorentzian manifold]]. Generalising the construction of a[[ two- form]] for a vector field on, on such a manifold a vector field defines an- form obtained by contracting with. The divergence is then the function defined byThe divergence can be defined in terms of the[[ Lie derivative]] asThis means that the divergence measures the rate of expansion of a unit of volume( a[[ volume element]])) as it flows with the vector field. On a[[ pseudo- Riemannian manifold]], the divergence with respect to the volume can be expressed in terms of the[[ Levi- Civita connection]]: where the second expression is the contraction of the vector field valued 1- form with itself and the last expression is the traditional coordinate expression from[[ Ricci calculus]]. An equivalent expression without using a connection iswhere is the[[ metric tensor| metric]]andformula_33 denotes the partial derivative with respect to coordinate. The square- root of the( absolute value of the[[ determinant]] of the) metric appears because the divergence must be written with the correct conception of the[[ volume]]. In curvilinear coordinates, the basis vectors are no longer orthonormal; the determinant encodes the correct idea of volume in this case. It appears twice, here, once,sothattheformula_34 can be transformed into" flat space"( where coordinates are actually orthonormal),andonceagainsothatformula_33 is also transformed into" flat space", so that finally, the" ordinary" divergence can be written with the" ordinary" concept of volume in flat space(" i. e." unit volume," i. e." one," i. e." not written down). The square- root appears in the denominator, because the derivative transforms in the opposite way([[ Covariance and contravariance of vectors| contravariantly]]) to the vector( which is[[ Covariance and contravariance of vectors| covariant]]). This idea of getting to a" flat coordinate system" where local computations can be done in a conventional way is called a[[ vielbein]]. A different way to see this is to note that the divergence is the[[ codifferential]] in disguise. That is,thedivergencecorrespondstotheexpressionformula_36withformula_37 the[[ differential of a function| differential]]andformula_38 the[[ Hodge star]]. The Hodge star, by its construction, causes the[[ volume form]] to appear in all of the right places. The divergence of tensors. Divergence can also be generalised to[[ tensors]]. In[[ Einstein notation]], the divergence of a[[ contravariant vector]] is given bywhere denotes the[[ covariant derivative]]. In this general setting, the correct formulation of the divergence is to recognize that it is a[[ codifferential]]; the appropriate properties follow from there. Equivalently, some authors define the divergence of a[[ mixed tensor]] by using the[[ musical isomorphism]]: if is a-[[ tensor]]( for the | contravariant vector and for the |
covariant one), then we define the" divergence of" to be the- tensorthat is, we take the trace over the" first two" covariant indices of the covariant derivative.Theformula_41 symbol refers to the[[ musical isomorphism]]. External links.[[ Category: Differential operators]][[ Category: Linear operators in calculus]][[ Category: Vector calculus]] In computability theory and computational complexity theory, a decision problem is a problem that can be posed as a yes– no question of the input values. An example of a decision problem is deciding whether a given natural number is prime. Another is the problem" given two numbers" x" and" y", does" x" evenly divide" y"?". The answer is either' yes' or' no' depending upon the values of" x" and" y". A method for solving a decision problem, given in the form of an algorithm, is called a decision procedure for that problem. A decision procedure for the decision problem" given two numbers" x" and" y", does" x" evenly divide" y"?" would give the steps for determining whether" x" evenly divides" y". One such algorithm is long division. If the remainder is zero the answer is' yes', otherwise it is' no'. A decision problem which can be solved by an algorithm is called" decidable". Decision problems typically appear in mathematical questions of decidability, that is, the question of the existence of an effective method to determine the existence of some object or its membership in a set; some of the most important problems in mathematics are undecidable. The field of computational complexity categorizes" decidable" decision problems by how difficult they are to solve." Difficult", in this sense, is described in terms of the computational resources needed by the most efficient algorithm for a certain problem. The field of recursion theory, meanwhile, categorizes" undecidable" decision problems by Turing degree, which is a measure of the noncomputability inherent in any solution. Definition. A" decision problem" is a yes- or- no question on an infinite set of inputs. It is traditional to define the decision problem as the set of possible inputs together with the set of inputs for which the answer is" yes". These inputs can be natural numbers, but can also be values of some other kind, like binary strings or strings over some other alphabet. The subset of strings for which the problem returns" yes" is a formal language, and often decision problems are defined as formal languages. Using an encoding such as Gödel numbering, any string can be encoded as a natural number, via which a decision problem can be defined as a subset of the natural numbers. Therefore, the algorithm of a decision problem is to compute the characteristic function of a subset of the natural numbers. Examples. A classic example of a decidable decision problem is the set of prime numbers. It is possible to effectively decide whether a given natural number is prime by testing every possible nontrivial factor. Although much more efficient methods of primality testing are known, the existence of any effective method is enough to establish decidability. Decidability. A decision problem is" decidable" or" effectively solvable" if the set | of inputs( or natural numbers) |
for which the answer is yes is a recursive set. A problem is" partially decidable"," semidecidable"," solvable", or" provable" if the set of inputs( or natural numbers) for which the answer is yes a recursively enumerable set. Problems that are not decidable are" undecidable". For those it is not possible to create an algorithm, efficient or otherwise, that solves them. The halting problem is an important undecidable decision problem; for more examples, see list of undecidable problems. Complete problems. Decision problems can be ordered according to many- one reducibility and related to feasible reductions such as polynomial- time reductions. A decision problem" P" is said to be" complete" for a set of decision problems" S" if" P" is a member of" S" and every problem in" S" can be reduced to" P". Complete decision problems are used in computational complexity theory to characterize complexity classes of decision problems. For example, the Boolean satisfiability problem is complete for the class NP of decision problems under polynomial- time reducibility. Function problems. Decision problems are closely related to function problems, which can have answers that are more complex than a simple' yes' or' no'. A corresponding function problem is" given two numbers" x" and" y", what is" x" divided by" y"?". A function problem consists of a partial function" f"; the informal" problem" is to compute the values of" f" on the inputs for which it is defined. Every function problem can be turned into a decision problem; the decision problem is just the graph of the associated function.( The graph of a function" f" is the set of pairs(" x"," y") such that" f"(" x")=" y".) If this decision problem were effectively solvable then the function problem would be as well. This reduction does not respect computational complexity, however. For example, it is possible for the graph of a function to be decidable in polynomial time( in which case running time is computed as a function of the pair(" x"," y")) when the function is not computable in polynomial time( in which case running time is computed as a function of" x" alone). The function" f"(" x")= 2" x" has this property. Every decision problem can be converted into the function problem of computing the characteristic function of the set associated to the decision problem. If this function is computable then the associated decision problem is decidable. However, this reduction is more liberal than the standard reduction used in computational complexity( sometimes called polynomial- time many- one reduction); for example, the complexity of the characteristic functions of an NP- complete problem and its co- NP- complete complement is exactly the same even though the underlying decision problems may not be considered equivalent in some typical models of computation. Optimization problems. Unlike decision problems, for which there is only one correct answer for each input, optimization problems are concerned with finding the" best" answer to a particular input. Optimization problems arise naturally in many applications, such as the traveling salesman problem and many questions in linear programming. There are standard techniques for transforming function and | optimization problems into decision problems. |
For example, in the traveling salesman problem, the optimization problem is to produce a tour with minimal weight. The associated decision problem is: for each" N", to decide whether the graph has any tour with weight less than" N". By repeatedly answering the decision problem, it is possible to find the minimal weight of a tour. Because the theory of decision problems is very well developed, research in complexity theory has typically focused on decision problems. Optimization problems themselves are still of interest in computability theory, as well as in fields such as operations research. The Domain Name System( DNS) is the hierarchical and decentralized naming system used to identify computers, services, and other resources reachable through the Internet or other Internet Protocol( IP) networks. The resource records contained in the DNS associate domain names with other forms of information. These are most commonly used to map human- friendly domain names to the numerical IP addresses computers need to locate services and devices using the underlying network protocols, but have been extended over time to perform many other functions as well. The Domain Name System has been an essential component of the functionality of the Internet since 1985. Function. An often- used analogy to explain the Domain Name System is that it serves as the phone book for the Internet by translating human- friendly computer hostnames into IP addresses. For example, the domain name www. example. com translates to the addresses(IPv4) and(IPv6). The DNS can be quickly and transparently updated, allowing a service' s location on the network to change without affecting the end users, who continue to use the same hostname. Users take advantage of this when they use meaningful Uniform Resource Locators( URLs) and e- mail addresses without having to know how the computer actually locates the services. An important and ubiquitous function of the DNS is its central role in distributed Internet services such as cloud services and content delivery networks. When a user accesses a distributed Internet service using a URL, the domain name of the URL is translated to the IP address of a server that is proximal to the user. The key functionality of the DNS exploited here is that different users can" simultaneously" receive different translations for the" same" domain name, a key point of divergence from a traditional phone- book view of the DNS. This process of using the DNS to assign proximal servers to users is key to providing faster and more reliable responses on the Internet and is widely used by most major Internet services. The DNS reflects the structure of administrative responsibility in the Internet. Each subdomain is a zone of administrative autonomy delegated to a manager. For zones operated by a registry, administrative information is often complemented by the registry' s RDAP and WHOIS services. That data can be used to gain insight on, and track responsibility for, a given host on the Internet. History. Using a simpler, more memorable name in place of a host' s numerical address dates back to the ARPANET era. The Stanford Research Institute( now | SRI International) maintained a text |
file named HOSTS. TXT that mapped host names to the numerical addresses of computers on the ARPANET. Elizabeth Feinler developed and maintained the first ARPANET directory. Maintenance of numerical addresses, called the Assigned Numbers List, was handled by Jon Postel at the University of Southern California' s Information Sciences Institute( ISI), whose team worked closely with SRI. Addresses were assigned manually. Computers, including their hostnames and addresses, were added to the primary file by contacting the SRI Network Information Center( NIC), directed by Feinler, telephone during business hours. Later, Feinler set up a WHOIS directory on a server in the NIC for retrieval of information about resources, contacts, and entities. She and her team developed the concept of domains. Feinler suggested that domains should be based on the location of the physical address of the computer. Computers at educational institutions would have the domain" edu", for example. She and her team managed the Host Naming Registry from 1972 to 1989.Bytheearly1980s, maintaining a single, centralized host table had become slow and unwieldy and the emerging network required an automated naming system to address technical and personnel issues. Postel directed the task of forging a compromise between five competing proposals of solutions to Paul Mockapetris. Mockapetris instead created the Domain Name System in 1983. The Internet Engineering Task Force published the original specifications in RFC 882 and RFC 883 in November 1983. In 1984, four UC Berkeley students, Douglas Terry, Mark Painter, David Riggle, and Songnian Zhou, wrote the first Unix name server implementation for the Berkeley Internet Name Domain, commonly referred to as BIND. In 1985, Kevin Dunlap of DEC substantially revised the DNS implementation. Mike Karels, Phil Almquist, and Paul Vixie have maintained BIND since then.Intheearly1990s, BIND was ported to the Windows NT platform. In November 1987, RFC 1034 and RFC 1035 superseded the 1983 DNS specifications. Several additional Request for Comments have proposed extensions to the core DNS protocols. Structure. Domain name space. The domain name space consists of a tree data structure. Each node or leaf in the tree has a" label" and zero or more" resource records"( RR), which hold information associated with the domain name. The domain name itself consists of the label, concatenated with the name of its parent node on the right, separated by a dot. The tree sub- divides into" zones" beginning at the root zone. A DNS zone may consist of only one domain, or may consist of many domains and sub- domains, depending on the administrative choices of the zone manager. DNS can also be partitioned according to" class" where the separate classes can be thought of as an array of parallel namespace trees. Administrative responsibility for any zone may be divided by creating additional zones. Authority over the new zone is said to be" delegated" to a designated name server. The parent zone ceases to be authoritative for the new zone. Domain name syntax, internationalization. The definitive descriptions of the rules for forming domain names appear in RFC 1035, RFC 1123, RFC 2181, and RFC 5892. A domain name consists of one | or more parts, technically called" |
labels", that are conventionally concatenated, and delimited by dots, such as example. com. The right- most label conveys the top- level domain; for example, the domain name www. example. com belongs to the top- level domain" com". The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example, the label" example" specifies a subdomain of the" com" domain, and" www" is a subdomain of example. com. This tree of subdivisions may have up to 127 levels. A label may contain zero to 63 characters. The null label, of length zero, is reserved for the root zone. The full domain name may not exceed the length of 253 characters in its textual representation. In the internal binary representation of the DNS the maximum length requires 255 octets of storage, as it also stores the length of the name. Although no technical limitation exists to prevent domain name labels using any character which is representable by an octet, hostnames use a preferred format and character set. The characters allowed in labels are a subset of the ASCII character set, consisting of characters" a" through" z"," A" through" Z", digits" 0" through" 9", and hyphen. This rule is known as the" LDH rule"( letters, digits, hyphen). Domain names are interpreted in case- independent manner. Labels may not start or end with a hyphen. An additional rule requires that top- level domain names should not be all- numeric. The limited set of ASCII characters permitted in the DNS prevented the representation of names and words of many languages in their native alphabets or scripts. To make this possible, ICANN approved the Internationalizing Domain Names in Applications( IDNA) system, by which user applications, such as web browsers, map Unicode strings into the valid DNS character set using Punycode. In 2009 ICANN approved the installation of internationalized domain name country code top- level domains(" ccTLD" s). In addition, many registries of the existing top- level domain names(" TLD" s) have adopted the IDNA system, guided by RFC 5890, RFC 5891, RFC 5892, RFC 5893. Name servers. The Domain Name System is maintained by a distributed database system, which uses the client– server model. The nodes of this database are the name servers. Each domain has at least one authoritative DNS server that publishes information about that domain and the name servers of any domains subordinate to it. The top of the hierarchy is served by the root name servers, the servers to query when looking up(" resolving") a TLD. Authoritative name server. An" authoritative" name server is a name server that only gives answers to DNS queries from data that has been configured by an original source, for example, the domain administrator or by dynamic DNS methods, in contrast to answers obtained via a query to another name server that only maintains a cache of data. An authoritative name server can either be a" primary" server or a" secondary" server. Historically the terms" master/ slave" and" primary/ secondary" were sometimes used interchangeably | but the current practice is |
to use the latter form. A primary server is a server that stores the original copies of all zone records. A secondary server uses a special automatic updating mechanism in the DNS protocol in communication with its primary to maintain an identical copy of the primary records. Every DNS zone must be assigned a set of authoritative name servers. This set of servers is stored in the parent domain zone with name server( NS) records. An authoritative server indicates its status of supplying definitive answers, deemed" authoritative", by setting a protocol flag, called the" Authoritative Answer"(" AA") bit in its responses. This flag is usually reproduced prominently in the output of DNS administration query tools, such as dig, to indicate" that the responding name server is an authority for the domain name in question." When a name server is designated as the authoritative server for a domain name for which it does not have authoritative data, it presents a type of error called a" lame delegation" or" lame response". Operation. Address resolution mechanism. Domain name resolvers determine the domain name servers responsible for the domain name in question by a sequence of queries starting with the right- most( top- level) domain label. For proper operation of its domain name resolver, a network host is configured with an initial cache(" hints") of the known addresses of the root name servers. The hints are updated periodically by an administrator by retrieving a dataset from a reliable source. Assuming the resolver has no cached records to accelerate the process, the resolution process starts with a query to one of the root servers. In typical operation, the root servers do not answer directly, but respond with a referral to more authoritative servers, e. g., a query for" www. wikipedia. org" is referred to the" org" servers. The resolver now queries the servers referred to, and iteratively repeats this process until it receives an authoritative answer. The diagram illustrates this process for the host that is named by the fully qualified domain name" www. wikipedia. org". This mechanism would place a large traffic burden on the root servers, if every resolution on the Internet required starting at the root. In practice caching is used in DNS servers to off- load the root servers, and as a result, root name servers actually are involved in only a relatively small fraction of all requests. Recursive and caching name server. In theory, authoritative name servers are sufficient for the operation of the Internet. However, with only authoritative name servers operating, every DNS query must start with recursive queries at the root zone of the Domain Name System and each user system would have to implement resolver software capable of recursive operation. To improve efficiency, reduce DNS traffic across the Internet, and increase performance in end- user applications, the Domain Name System supports DNS cache servers which store DNS query results for a period of time determined in the configuration(" time- to- live") of the domain name record in question. Typically, such caching DNS servers also implement the recursive algorithm necessary | to resolve a given name |
starting with the DNS root through to the authoritative name servers of the queried domain. With this function implemented in the name server, user applications gain efficiency in design and operation. The combination of DNS caching and recursive functions in a name server is not mandatory; the functions can be implemented independently in servers for special purposes. Internet service providers typically provide recursive and caching name servers for their customers. In addition, many home networking routers implement DNS caches and recursion to improve efficiency in the local network. DNS resolvers. The client side of the DNS is called a DNS resolver. A resolver is responsible for initiating and sequencing the queries that ultimately lead to a full resolution( translation) of the resource sought, e. g., translation of a domain name into an IP address. DNS resolvers are classified by a variety of query methods, such as" recursive"," non- recursive", and" iterative". A resolution process may use a combination of these methods. In a" non- recursive query", a DNS resolver queries a DNS server that provides a record either for which the server is authoritative, or it provides a partial result without querying other servers. In case of a caching DNS resolver, the non- recursive query of its local DNS cache delivers a result and reduces the load on upstream DNS servers by caching DNS resource records for a period of time after an initial response from upstream DNS servers. In a" recursive query", a DNS resolver queries a single DNS server, which may in turn query other DNS servers on behalf of the requester. For example, a simple stub resolver running on a home router typically makes a recursive query to the DNS server run by the user' s ISP. A recursive query is one for which the DNS server answers the query completely by querying other name servers as needed. In typical operation, a client issues a recursive query to a caching recursive DNS server, which subsequently issues non- recursive queries to determine the answer and send a single answer back to the client. The resolver, or another DNS server acting recursively on behalf of the resolver, negotiates use of recursive service using bits in the query headers. DNS servers are not required to support recursive queries. The" iterative query" procedure is a process in which a DNS resolver queries a chain of one or more DNS servers. Each server refers the client to the next server in the chain, until the current server can fully resolve the request. For example, a possible resolution of www. example. com would query a global root server, then a" com" server, and finally an" example. com" server. Circular dependencies and glue records. Name servers in delegations are identified by name, rather than by IP address. This means that a resolving name server must issue another DNS request to find out the IP address of the server to which it has been referred. If the name given in the delegation is a subdomain of the domain for which the delegation is being provided, there is | a circular dependency. In this |
case, the name server providing the delegation must also provide one or more IP addresses for the authoritative name server mentioned in the delegation. This information is called" glue". The delegating name server provides this glue in the form of records in the" additional section" of the DNS response, and provides the delegation in the" authority section" of the response. A glue record is a combination of the name server and IP address. For example, if the authoritative name server for example.orgisns1. example. org, a computer trying to resolve www. example.orgfirstresolvesns1. example. org.Asns1 is contained in example. org, this requires resolving example. org first, which presents a circular dependency. To break the dependency, the name server for the top level domain org includes glue along with the delegation for example. org.ThegluerecordsareaddressrecordsthatprovideIPaddressesforns1. example. org. The resolver uses one or more of these IP addresses to query one of the domain' s authoritative servers, which allows it to complete the DNS query. Record caching. A standard practice in implementing name resolution in applications is to reduce the load on the Domain Name System servers by caching results locally, or in intermediate resolver hosts. Results obtained from a DNS request are always associated with the time to live( TTL), an expiration time after which the results must be discarded or refreshed. The TTL is set by the administrator of the authoritative DNS server. The period of validity may vary from a few seconds to days or even weeks. As a result of this distributed caching architecture, changes to DNS records do not propagate throughout the network immediately, but require all caches to expire and to be refreshed after the TTL. RFC 1912 conveys basic rules for determining appropriate TTL values. Some resolvers may override TTL values, as the protocol supports caching for up to sixty- eight years or no caching at all. Negative caching, i. e. the caching of the fact of non- existence of a record, is determined by name servers authoritative for a zone which must include the Start of Authority( SOA) record when reporting no data of the requested type exists. The value of the" minimum" field of the SOA record and the TTL of the SOA itself is used to establish the TTL for the negative answer. Reverse lookup. A reverse DNS lookup is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer( PTR) records within the infrastructure top- level domain arpa.ForIPv4, the domain is in- addr. arpa.ForIPv6, the reverselookupdomainisip6. arpa. The IP address is represented as a name in reverse- ordered octetrepresentationforIPv4, and reverse- ordered nibblerepresentationforIPv6. When performing a reverse lookup, the DNS client converts the address into these formats before querying the name for a PTR record following the delegation chain as for any DNS query. For example, assuming theIPv4 address 208. 80. 152. 2 is assigned to Wikimedia, it is represented as a DNS name in | reverse order: 2. 152. 80. |
208. in- addr. arpa. When the DNS resolver gets a pointer( PTR) request, it begins by querying the root servers, which point to the servers of American Registry for Internet Numbers( ARIN) for the 208. in- addr. arpa zone. ARIN' s servers delegate 152. 80. 208. in- addr. arpa to Wikimedia to which the resolver sends another query for 2. 152. 80. 208. in- addr. arpa, which results in an authoritative response. Client lookup. Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in applications such as web browsers, e- mail clients, and other Internet applications. When an application makes a request that requires a domain name lookup, such programs send a resolution request to the DNS resolver in the local operating system, which in turn handles the communications required. The DNS resolver will almost invariably have a cache( see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to one or more designated DNS servers. In the case of most home users, the Internet service provider to which the machine connects will usually supply this DNS server: such a user will either have configured that server' s address manually or allowed DHCP to set it; however, where systems administrators have configured systems to use their own DNS servers, their DNS resolvers point to separately maintained name servers of the organization. In any event, the name server thus queried will follow the process outlined above, until it either successfully finds a result or does not. It then returns its results to the DNS resolver; assuming it has found a result, the resolver duly caches that result for future use, and hands the result back to the software which initiated the request. Broken resolvers. Some large ISPs have configured their DNS servers to violate rules, such as by disobeying TTLs, or by indicating that a domain name does not exist just because one of its name servers does not respond. Some applications such as web browsers maintain an internal DNS cache to avoid repeated lookups via the network. This practice can add extra difficulty when debugging DNS issues as it obscures the history of such data. These caches typically use very short caching times on the order of one minute. Internet Explorer represents a notable exception: versions up to IE 3. x cache DNS records for 24 hours by default. Internet Explorer 4. x and later versions( up to IE 8) decrease the default timeout value to half an hour, which may be changed by modifying the default configuration. When Google Chrome detects issues with the DNS server it displays a specific error message. Other applications. The Domain Name System includes several other functions and features. Hostnames and IP addresses are not required to match in a one- to- one relationship. Multiple hostnames may correspond to a single IP address, which | is useful in virtual hosting, |
in which many web sites are served from a single host. Alternatively, a single hostname may resolve to many IP addresses to facilitate fault tolerance and load distribution to multiple server instances across an enterprise or the global Internet. DNS serves other purposes in addition to translating names to IP addresses. For instance, mail transfer agents use DNS to find the best mail server to deliver e- mail: An MX record provides a mapping between a domain and a mail exchanger; this can provide an additional layer of fault tolerance and load distribution. The DNS is used for efficient storage and distribution of IP addresses of blacklisted email hosts. A common method is to place the IP address of the subject host into the sub- domain of a higher level domain name, and to resolve that name to a record that indicates a positive or a negative indication. For example: E- mail servers can query blacklist. example to find out if a specific host connecting to them is in the blacklist. Many of such blacklists, either subscription- based or free of cost, are available for use by email administrators and anti- spam software. To provide resilience in the event of computer or network failure, multiple DNS servers are usually provided for coverage of each domain. At the top level of global DNS, thirteen groups of root name servers exist, with additional" copies" of them distributed worldwide via anycast addressing. Dynamic DNS( DDNS) updates a DNS server with a client IP address on- the- fly, for example, when moving between ISPs or mobile hot spots, or when the IP address changes administratively. DNS message format. The DNS protocol uses two types of DNS messages, queries and replies; both have the same format. Each message consists of a header and four sections: question, answer, authority, and an additional space. A header field(" flags") controls the content of these four sections. The header section consists of the following fields:" Identification"," Flags"," Number of questions"," Number of answers"," Number of authority resource records"( RRs), and" Number of additional RRs". Each field is 16 bits long, and appears in the order given. The identification field is used to match responses with queries. The flag field consists of sub- fields as follows: After the flag, the header ends with four 16- bit integers which contain the number of records in each of the sections that follow, in the same order. Question section. The question section has a simpler format than the resource record format used in the other sections. Each question record( there is usually just one in the section) contains the following fields: The domain name is broken into discrete labels which are concatenated; each label is prefixed by the length of that label. DNS transport protocols. DNS- over- UDP/ 53("Do53"). From the time of its origin in 1983 until quite recently, DNS has primarily answered queries on User Datagram Protocol( UDP) port number 53. Such queries consist of a clear- text request sent in a single UDP packet from the client, responded to with a clear- | text reply sent in a |
single UDP packet from the server. When the length of the answer exceeds 512 bytes and both client and server support Extension Mechanisms for DNS( EDNS), larger UDP packets may be used. Use of DNS- over- UDP is limited by, among other things, its lack of transport- layer encryption, authentication, reliable delivery, and message length. DNS- over- TCP/ 53("Do53/ TCP"). In 1989, RFC 1123 specified optional Transmission Control Protocol( TCP) transport for DNS queries, replies and, particularly, zone transfers. Via fragmentation of long replies, TCP allows longer responses, reliable delivery, and re- use of long- lived connections between clients and servers. DNSCrypt. The DNSCrypt protocol, which was developed in 2011 outside the IETF standards framework, introduced DNS encryption on the downstream side of recursive resolvers, wherein clients encrypt query payloads using servers' public keys, which are published in the DNS( rather than relying upon third- party certificate authorities) and which may in turn be protected by DNSSEC signatures. DNSCrypt uses either TCP or UDP port 443, the same port as HTTPS encrypted web traffic. This introduced not only privacy regarding the content of the query, but also a significant measure of firewall- traversal capability. In 2019, DNSCrypt was further extended to support an" anonymized" mode, similar to the proposed" Oblivious DNS," in which an ingress node receives a query which has been encrypted with the public key of a different server, and relays it to that server, which acts as an egress node, performing the recursive resolution. Privacy of user/ query pairs is created, since the ingress node does not know the content of the query, while the egress nodes does not know the identity of the client. DNSCrypt was first implemented in production by OpenDNS in December of 2011. DNS- over- TLS(" DoT"). An IETF standard for encrypted DNS emerged in 2016, utilizing standard Transport Layer Security( TLS) to protect the entire connection, rather than just the DNS payload. DoT servers listen on TCP port 853.RFC7858 specifies that opportunistic encryption and authenticated encryption may be supported, but did not make either server or client authentication mandatory. DNS- over- HTTPS(" DoH"). A competing standard for DNS query transport was introduced in 2018, tunneling DNS query data over HTTPS( which in turn transports HTTP over TLS). DoH was promoted as a more web- friendly alternative to DNS since, like DNSCrypt, it travels on TCP port 443, and thus looks similar to web traffic, though they are easily differentiable in practice. DoH has been widely criticized for decreasing user anonymity relative to DoT. DNS- over- TOR. Like other Internet protocols, DNS may be run over VPNs and tunnels. One use which has become common enough since 2019 to warrant its own frequently used acronym is DNS- over- Tor. The privacy gains of Oblivious DNS can be garnered through the use of the preexisting Tor network of ingress and egress nodes, paired with the transport- layer encryption provided by TLS. Oblivious DNS- over- HTTPS(" ODoH"). In 2021, an" oblivious" implementation of DoH was proposed and has been implemented in draft form, combining ingress/ egress separation | with HTTPS tunneling and TLS |
transport- layer encryption in a single defined protocol. Resource records. The Domain Name System specifies a database of information elements for network resources. The types of information elements are categorized and organized with a list of DNS record types, the resource records( RRs). Each record has a type( name and number), an expiration time( time to live), a class, and type- specific data. Resource records of the same type are described as a" resource record set"( RRset), having no special ordering. DNS resolvers return the entire set upon query, but servers may implement round- robin ordering to achieve load balancing. In contrast, the Domain Name System Security Extensions( DNSSEC) work on the complete set of resource record in canonical order. When sent over an Internet Protocol network, all records use the common format specified in RFC 1035:" NAME" is the fully qualified domain name of the node in the tree. On the wire, the name may be shortened using label compression where ends of domain names mentioned earlier in the packet can be substituted for the end of the current domain name." TYPE" is the record type. It indicates the format of the data and it gives a hint of its intended use. For example, the" A"recordisusedtotranslatefromadomainnametoanIPv4 address, the" NS" record lists which name servers can answer lookups on a DNS zone, and the" MX" record specifies the mail server used to handle mail for a domain specified in an e- mail address." RDATA" is data of type- specific relevance, such as the IP address for address records, or the priority and hostname for MX records. Well known record types may use label compression in the RDATA field, but" unknown" record types must not( RFC 3597). The" CLASS" of a record is set to IN( for" Internet") for common DNS records involving Internet hostnames, servers, or IP addresses. In addition, the classes Chaos( CH) and Hesiod( HS) exist. Each class is an independent name space with potentially different delegations of DNS zones. In addition to resource records defined in a zone file, the domain name system also defines several request types that are used only in communication with other DNS nodes(" on the wire"), such as when performing zone transfers( AXFR/ IXFR) or for EDNS( OPT). Wildcard DNS records. The domain name system supports wildcard DNS records which specify names that start with the" asterisk label",'*', e. g.,*. example. DNS records belonging to wildcard domain names specify rules for generating resource records within a single DNS zone by substituting whole labels with matching components of the query name, including any specified descendants. For example, in the following configuration, the DNS zone" x. example" specifies that all subdomains, including subdomains of subdomains, of" x. example" use the mail exchanger( MX)" a. x. example". The A record for" a. x. example" is needed to specify the mail exchanger IP address. As this has the result of excluding this domain name and its subdomains from the wildcard matches, an additional MX record for the subdomain" a. x. example", as well as a wildcarded MX record | for all of its subdomains, |
must also be defined in the DNS zone. x. example. MX 10 a. x. example. a. x. example. MX 10 a. x. example. a. x. example. AAAA 2001:db8::1The role of wildcard records was refined in, because the original definition in was incomplete and resulted in misinterpretations by implementers. Protocol extensions. The original DNS protocol had limited provisions for extension with new features. In 1999, Paul Vixie published in RFC 2671( superseded by RFC 6891) an extension mechanism, called Extension Mechanisms for DNS( EDNS) that introduced optional protocol elements without increasing overhead when not in use. This was accomplished through the OPT pseudo- resource record that only exists in wire transmissions of the protocol, but not in any zone files. Initial extensions were also suggested(EDNS0), such as increasing the DNS message size in UDP datagrams. Dynamic zone updates. Dynamic DNS updates use the UPDATE DNS opcode to add or remove resource records dynamically from a zone database maintained on an authoritative DNS server. The feature is described in RFC 2136. This facility is useful to register network clients into the DNS when they boot or become otherwise available on the network. As a booting client may be assigned a different IP address each time from a DHCP server, it is not possible to provide static DNS assignments for such clients. Security issues. Originally, security concerns were not major design considerations for DNS software or any software for deployment on the early Internet, as the network was not open for participation by the general public. However,theexpansionoftheInternetintothecommercialsectorinthe1990s changed the requirements for security measures to protect data integrity and user authentication. Several vulnerability issues were discovered and exploited by malicious users. One such issue is DNS cache poisoning, in which data is distributed to caching resolvers under the pretense of being an authoritative origin server, thereby polluting the data store with potentially false information and long expiration times( time- to- live). Subsequently, legitimate application requests may be redirected to network hosts operated with malicious intent. DNS responses traditionally do not have a cryptographic signature, leading to many attack possibilities; the Domain Name System Security Extensions( DNSSEC) modify DNS to add support for cryptographically signed responses. DNSCurve has been proposed as an alternative to DNSSEC. Other extensions, such as TSIG, add support for cryptographic authentication between trusted peers and are commonly used to authorize zone transfer or dynamic update operations. Some domain names may be used to achieve spoofing effects. For example,andpaypa1. com are different names, yet users may be unable to distinguish them in a graphical user interface depending on the user' s chosen typeface. In many fonts the letter" l" and the numeral" 1" look very similar or even identical. This problem is acute in systems that support internationalized domain names, as many character codes in ISO 10646 may appear identical on typical computer screens. This vulnerability is occasionally exploited in phishing. Techniques such as forward- confirmed reverse DNS can also be used to help validate DNS results. DNS can also" leak" from otherwise secure or private connections, if attention is not paid to their | configuration, and at times DNS |
has been used to bypass firewalls by malicious persons, and exfiltrate data, since it is often seen as innocuous. Privacy and tracking issues. Originally designed as a public, hierarchical, distributed and heavily cached database, DNS protocol has no confidentiality controls. User queries and nameserver responses are being sent unencrypted which enables network packet sniffing, DNS hijacking, DNS cache poisoning and man- in- the- middle attacks. This deficiency is commonly used by cybercriminals and network operators for marketing purposes, user authentication on captive portals and censorship. User privacy is further exposed by proposals for increasing the level of client IP information in DNS queries( RFC 7871) for the benefit of Content Delivery Networks. The main approaches that are in use to counter privacy issues with DNS: Solutions preventing DNS inspection by local network operator are criticized for thwarting corporate network security policies and Internet censorship. They are also criticized from a privacy point of view, as giving away the DNS resolution to the hands of a small number of companies known for monetizing user traffic and for centralizing DNS name resolution, which is generally perceived as harmful for the Internet. Domain name registration. The right to use a domain name is delegated by domain name registrars which are accredited by the Internet Corporation for Assigned Names and Numbers( ICANN) or other organizations such as OpenNIC, that are charged with overseeing the name and number systems of the Internet. In addition to ICANN, each top- level domain( TLD) is maintained and serviced technically by an administrative organization, operating a registry. A" registry" is responsible for operating the database of names within its authoritative zone, although the term is most often used for TLDs. A" registrant" is a person or organization who asked for domain registration. The registry receives registration information from each domain name" registrar", which is authorized( accredited) to assign names in the corresponding zone and publishes the information using the WHOIS protocol. As of 2015, usage of RDAP is being considered. ICANN publishes the complete list of TLDs, TLD registries, and domain name registrars. Registrant information associated with domain names is maintained in an online database accessible with the WHOIS service. For most of the more than 290 country code top- level domains( ccTLDs), the domain registries maintain the WHOIS( Registrant, name servers, expiration dates, etc.) information. For instance, DENIC, Germany NIC, holds the DE domain data. From about 2001, most Generic top- level domain( gTLD) registries have adopted this so- called" thick" registry approach, i. e. keeping the WHOIS data in central registries instead of registrar databases. For top- level domains on COM and NET, a" thin" registry model is used. The domain registry( e. g., GoDaddy, BigRock and PDR, VeriSign, etc., etc.) holds basic WHOIS data( i. e., registrar and name servers, etc.). Organizations, or registrants using ORG on the other hand, are on the Public Interest Registry exclusively. Some domain name registries, often called" network information centers"( NIC), also function as registrars to end- users, in addition to providing access to the WHOIS datasets. The top- level domain registries, | such as for the domains |
COM, NET, and ORG use a registry- registrar model consisting of many domain name registrars. In this method of management, the registry only manages the domain name database and the relationship with the registrars. The" registrants"( users of a domain name) are customers of the registrar, in some cases through additional subcontracting of resellers. RFC documents. Standards. The Domain Name System is defined by Request for Comments( RFC) documents published by the Internet Engineering Task Force( Internet standards). The following is a list of RFCs that define the DNS protocol. Informational RFCs. These RFCs are advisory in nature, but may provide useful information despite defining neither a standard or BCP.( RFC 1796) Unknown. These RFCs have an official status of Unknown, but due to their age are not clearly labeled as such. David Michael Letterman( born April 12, 1947) is an American television host, comedian, writer, and producer. He hosted late night television talk shows for 33 years, beginning with the February 1, 1982, debut of" Late Night with David Letterman" on NBC, and ending with the May 20, 2015, broadcast of" Late Show with David Letterman" on CBS. In total, Letterman hosted 6, 080 episodes of" Late Night" and" Late Show", surpassing his friend and mentor Johnny Carson as the longest- serving late night talk show host in American television history. In 1996,Lettermanwasranked45th on" TV Guide" s 50 Greatest TV Stars of All Time. In 2002," The Late Show with David Letterman" was ranked seventh on TV Guide' s 50 Greatest TV Shows of All Time. He is also a television and film producer. His company, Worldwide Pants, produced his shows as well as" The Late Late Show" and several prime- time comedies, the most successful of which was" Everybody Loves Raymond", now in syndication. Several late- night hosts have cited Letterman' s influence, including Conan O' Brien( his successor on" Late Night"), Stephen Colbert( his successor on" The Late Show"), Jimmy Fallon, Jimmy Kimmel, John Oliver, and Seth Meyers. Letterman currently hosts the Netflix series" My Next Guest Needs No Introduction with David Letterman". Early life and career. Letterman was born in Indianapolis, Indiana, in 1947, and has two sisters, one older and one younger. His father, Harry Joseph Letterman( April 15, 1915– February 13, 1973), was a florist. His mother, Dorothy Marie Letterman Mengering( née Hofert; July 18, 1921– April 11, 2017), a church secretary for the Second Presbyterian Church of Indianapolis, was an occasional figure on Letterman' s show, usually at holidays and birthdays. Letterman grew up on the north side of Indianapolis, in the Broad Ripple area, about 12 miles from the Indianapolis Motor Speedway. He enjoyed collecting model cars, including racers. In 2000, he told an interviewer for" Esquire" that, while growing up, he admired his father' s ability to tell jokes and be the life of the party. Harry Joseph Letterman survived a heart attack at the age of 36 when David was a young boy. The fear of losing his father was constantly with Letterman as he grew up. The elder Letterman died of | a second heart attack in |
1973, at the age of 57. Letterman attended his hometown' s Broad Ripple High School and worked as a stock boy at the local Atlas Supermarket. According to the" Ball State Daily News", he originally wanted to attend Indiana University, but his grades were not good enough, so he instead attended Ball State University, in Muncie, Indiana. He is a member of the Sigma Chi fraternity, and graduated in 1969 from what was then the Department of Radio and Television. A self- described average student, Letterman later endowed a scholarship for what he called" C students" at Ball State. Though he registered for the draft and passed his physical after graduating from college, he was not drafted for service in Vietnam because he received a draft lottery number of 346( out of 366). Letterman began his broadcasting career as an announcer and newscaster at the college' s student- run radio station— WBST— a 10- watt campus station that is now part of Indiana Public Radio. He was fired for treating classical music with irreverence. He then became involved with the founding of another campus station— WAGO- AM 570( now WWHI, 91. 3). He credits Paul Dixon, host of the" Paul Dixon Show", a Cincinnati- based talk show also shown in Indianapolis while he was growing up, for inspiring his choice of career: I was just out of college[ in 1969], and I really didn' t know what I wanted to do. And then all of a sudden I saw him doing it[ on TV]. And I thought: That' s really what I want to do! Weatherman. Soon after graduating from Ball State in 1969, Letterman began his career as a radio talk show host on WNTS( AM) and on Indianapolis television station WLWI( which changed its call sign to WTHR in 1976) as an anchor and weatherman. He received some attention for his unpredictable on- air behavior, which included congratulating a tropical storm for being upgraded to a hurricane and predicting hailstones" the size of canned hams." He also occasionally reported the weather and the day' s very high and low temps for fictitious cities(" Eight inches of snow in Bingree and surrounding areas"), on another occasion saying that the state border between Indiana and Ohio had been erased when a satellite map accidentally omitted it, attributing it to dirty political dealings.(" The higher- ups have removed the border between Indiana and Ohio, making it one giant state. Personally, I' m against it. I don' t know what to do about it.") He also starred in a local kiddie show, made wisecracks as host of a late- night TV show called" Freeze- Dried Movies"( he once acted out a scene from" Godzilla" using plastic dinosaurs), and hosted a talk show that aired early on Saturday mornings called" Clover Power", in which he interviewed 4- H members about their projects. In 1971, Letterman appeared as a pit road reporter for ABC Sports' tape- delayed coverage of the Indianapolis 500, which was his first nationally telecast appearance( WLWI was the local ABC affiliate at | the time). He was initially |
introduced as Chris Economaki, but this was corrected at the end of the interview( Jim McKay announced his name as Dave Letterman). Letterman interviewed Mario Andretti, who had just crashed out of the race. Move to Los Angeles. In 1975, encouraged by his then- wife Michelle and several of his Sigma Chi fraternity brothers, Letterman moved to Los Angeles, California, with the hope of becoming a comedy writer. He and Michelle packed their belongings in his pickup truck and headed west. As of 2012, he still owned the truck. In Los Angeles, he began performing comedy at The Comedy Store. Jimmie Walker saw him on stage; with an endorsement from George Miller, Letterman joined a group of comedians whom Walker hired to write jokes for his stand- up act, a group that at various times also included Jay Leno, Paul Mooney, Robert Schimmel, Richard Jeni, Louie Anderson, Elayne Boosler, Byron Allen, Jack Handey, and Steve Oedekerk. By the summer of 1977, Letterman was a writer and regular on the six- week summer series" The Starland Vocal Band Show", broadcast on CBS. He hosted a 1977 pilot for a game show called" The Riddlers"( which was never picked up), and co- starred in the Barry Levinson- produced comedy special" Peeping Times", which aired in January 1978. Later that year, Letterman was a cast member on Mary Tyler Moore' s variety show," Mary". He made a guest appearance on" Mork& amp; Mindy"( as a parody of EST leader Werner Erhard) and appearances on game shows such as" The$ 20, 000 Pyramid"," The Gong Show"," Hollywood Squares"," Password Plus", and" Liar' s Club", as well as the Canadian cooking show" Celebrity Cooks"( November 1977), talk shows such as" 90 Minutes Live"( February 24 and April 14, 1978), and" The Mike Douglas Show"( April 3, 1979 and February 7, 1980). He was also screen tested for the lead role in the 1980 film" Airplane!", a role that eventually went to Robert Hays. Letterman' s brand of dry, sarcastic humor caught the attention of scouts for" The Tonight Show Starring Johnny Carson", and he was soon a regular guest on the show. He became a favorite of Carson and was a regular guest host for the show beginning in 1978. Letterman credits Carson as the person who influenced his career the most. NBC. Morning show. On June 23, 1980, Letterman was given his own morning comedy show on NBC," The David Letterman Show". It was originally 90 minutes long but was shortened to 60 minutes in August 1980. The show was a critical success, winning two Emmy Awards, but was a ratings disappointment and was canceled, the last show airing October 24, 1980." Late Night with David Letterman". NBC kept Letterman on its payroll to try him in a different time slot." Late Night with David Letterman" debuted February 1, 1982; the first guest was Bill Murray. Murray went on to become one of Letterman' s most recurrent guests, guesting on his later CBS show' s celebration of his30th anniversary in late- night television, which aired January | 31, 2012, and on the |
final CBS show, which aired May 20, 2015. The show ran Monday through Thursday nights at 12: 30 a. m. Eastern Time, immediately following" The Tonight Show Starring Johnny Carson"( a Friday night broadcast was added in June 1987). It was seen as edgy and unpredictable, and soon developed a cult following( particularly among college students). Letterman' s reputation as an acerbic interviewer was borne out in verbal sparring matches with Cher( who even called him an" asshole" on the show), Shirley MacLaine, Charles Grodin, and Madonna. The show also featured comedy segments and running characters,inastyleheavilyinfluencedbythe1950sand1960s programs of Steve Allen. The show often featured quirky, genre- mocking regular features, including" Stupid Pet Tricks"( which had its origins on Letterman' s morning show), Stupid Human Tricks, dropping various objects off the roof of a five- story building, demonstrations of unorthodox clothing( such as suits made of Alka- Seltzer, Velcro and suet), a recurring Top 10 list, the Monkey- Cam( and the Audience Cam), a facetious letter- answering segment, several" Film[ s] by My Dog Bob" in which a camera was mounted on Letterman' s own dog( often with comic results) and Small Town News, all of which moved with Letterman to CBS. Other episodes included Letterman using a bullhorn to interrupt a live interview on" The Today Show" on August 19, 1985, announcing that he was the NBC News president Lawrence K. Grossman and that he was not wearing any pants;walkingacrossthehalltoStudio6B, at the time the news studio for WNBC- TV, and interrupting Al Roker' s weather segments during" Live at Five"; and staging" elevator races", complete with commentary by NBC Sports' Bob Costas. In one appearance, in 1982, Andy Kaufman( who was wearing a neck brace) appeared with professional wrestler Jerry Lawler, who slapped and knocked the comedian to the ground( Lawler and Kaufman' s friend Bob Zmuda later revealed that the incident was staged). CBS." Late Show with David Letterman". In 1992, Johnny Carson retired and many fans believed that Letterman would become host of" The Tonight Show". When NBC instead gave the job to Jay Leno, Letterman departed NBC to host his own late- night show on CBS, opposite" The Tonight Show" at 11: 30 p. m., called the" Late Show with David Letterman". The new show debuted on August 30, 1993, and was taped at the historic Ed Sullivan Theater, where Ed Sullivan broadcast his eponymous variety series from 1948 to 1971. For Letterman' s arrival, CBS spent$ 8 million in renovations. CBS also signed Letterman to a three- year,$ 14 million/ year contract, doubling his" Late Night" salary. But while the expectation was that Letterman would retain his unique style and sense of humor with the move," Late Show" was not an exact replica of his old NBC program. The monologue was lengthened. Paul Shaffer and the World' s Most Dangerous Band followed Letterman to CBS, but they added a brass section and were rebranded the CBS Orchestra( at Shaffer' s request); a small band had been mandated by Carson while Letterman occupied the 12: 30 slot. Additionally, because | of intellectual property disagreements, Letterman |
was unable to import many of his" Late Night" segments verbatim, but he sidestepped this problem by simply renaming them( the" Top Ten List" became the" Late Show Top Ten"," Viewer Mail" became the" CBS Mailbag", etc.)." Time" magazine wrote," Letterman' s innovation... gained power from its rigorous formalism"; as his biographer Jason Zinoman puts it, he was" a fascinatingly disgruntled eccentric trapped inside a more traditional talk show." Popularity. The" Late Show"' s main competitor was NBC' s" The Tonight Show", which Jay Leno hosted for 22 years, except from June 1, 2009, to January 22, 2010, when Conan O' Brien hosted. In 1993 and 1994, the" Late Show" consistently gained higher ratings than" The Tonight Show". But in 1995, ratings dipped and Leno' s show consistently beat Letterman' s in the ratings from the time that Hugh Grant came on Leno' s show after Grant' s arrest for soliciting a prostitute. Leno typically attracted about five million nightly viewers between 1999 and 2009. The" Late Show" lost nearly half its audience during its competition with Leno, attracting 7. 1 million viewers nightly in its 1993– 94 season and about 3. 8 million per night as of Leno' s departure in 2009. In the final months of his first stint as host of" The Tonight Show", Leno beat Letterman in the ratings by a 1. 3 million- viewer margin( 5. 2 million to 3. 9 million), and" Nightline" and the" Late Show" were virtually tied. Once O' Brien took over" Tonight", Letterman closed the gap in the ratings. O' Brien initially drove the median age of" Tonight Show" viewers from 55 to 45, with most older viewers opting to watch the" Late Show" instead. After Leno returned to" The Tonight Show", Leno regained his lead. Letterman' s shows have garnered both critical and industry praise, receiving 67 Emmy Award nominations, winning 12 times in his first 20 years in late night television. From 1993 to 2009, Letterman ranked higher than Leno in the annual Harris Poll of" Nation' s Favorite TV Personality" 12 times. For example, in 2003 and 2004 Letterman ranked second in that poll, behind only Oprah Winfrey, a year that Leno was ranked fifth. Leno was higher than Letterman on that poll three times during the same period, in 1998, 2007, and 2008. Hosting the Academy Awards. On March 27, 1995,Lettermanhostedthe67th Academy Awards ceremony. Critics blasted what they deemed his poor performance, noting that his irreverent style undermined the traditional importance and glamor of the event. In a joke about their unusual names( inspired by a celebrated comic essay in" The New Yorker"," Yma Dream" by Thomas Meehan), he started off by introducing Uma Thurman to Oprah Winfrey, and then both of them to Keanu Reeves:" Oprah... Uma. Uma... Oprah,"" Have you kids met Keanu?" This and many of his other jokes fell flat. Although Letterman attracted the highest ratings to the annual telecast since 1983, many felt that the bad publicity he generated caused a decline in the" Late Show"' s ratings. Letterman recycled the apparent debacle | into a long- running gag. |
On his first show after the Oscars, he joked," Looking back, I had no idea that thing was being televised." He lampooned his stint two years later, during Billy Crystal' s opening Oscar skit, which also parodied the plane- crashing scenes from that year' s chief nominated film," The English Patient". For years afterward, Letterman recounted his hosting the Oscars, although the Academy of Motion Picture Arts and Sciences continued to hold Letterman in high regard and invited him to host the Oscars again. On September 7, 2010,hemadeanappearanceonthepremiereofthe14th season of" The View", and confirmed that he had been considered for hosting again. Heart surgery hiatus. On January 14, 2000, a routine check- up revealed that an artery in Letterman' s heart was severely obstructed. He was rushed to emergency surgery for a quintuple bypass at New York Presbyterian Hospital. During the initial weeks of his recovery, reruns of the" Late Show" were shown and introduced by friends of Letterman including Norm Macdonald, Drew Barrymore, Ray Romano, Robin Williams, Bonnie Hunt, Megan Mullally, Bill Murray, Regis Philbin, Charles Grodin, Nathan Lane, Julia Roberts, Bruce Willis, Jerry Seinfeld, Martin Short, Steven Seagal, Hillary Clinton, Danny DeVito, Steve Martin, and Sarah Jessica Parker. Subsequently, while still recovering from surgery, Letterman revived the late- night talk show tradition of" guest hosts"thathadvirtuallydisappearedonnetworktelevisionduringthe1990s, allowing Bill Cosby, Kathie Lee Gifford, Dana Carvey, Janeane Garofalo, and others to host new episodes of the" Late Show". Upon his return to the show on February 21, 2000, Letterman brought all but one of the doctors and nurses on stage who had participated in his surgery and recovery( with extra teasing of a nurse who had given him bed baths—" This woman gave me a bath!"), including Dr. O. Wayne Isom and physician Louis Aronne, who frequently appeared on the show. In a show of emotion, Letterman was nearly in tears as he thanked the health care team with the words" These are the people who saved my life!" The episode earned an Emmy nomination. For a number of episodes, Letterman continued to crack jokes about his bypass, including saying," Bypass surgery: it' s when doctors surgically create new blood flow to your heart. A bypass is what happened to me when I didn' t get" The Tonight Show!" It' s a whole different thing." In a later running gag, he lobbied Indiana to rename the freeway circling Indianapolis( I- 465)" The David Letterman Bypass". He also featured a montage of faux news coverage of his bypass surgery, which included a clip of Letterman' s heart for sale on the Home Shopping Network. Letterman became friends with his doctors and nurses. In 2008, a" Rolling Stone" interview stated he hosted a doctor and nurse who' d helped perform the emergency quintuple- bypass heart surgery that saved his life in 2000.' These are people who were complete strangers when they opened my chest,' he says.' And now, eight years later, they' re among my best friends.' Additionally, Letterman invited the band Foo Fighters to play" Everlong", introducing them as" my favorite band, playing my | favorite song." During Letterman' s |
last show, on which Foo Fighters appeared, Letterman said that Foo Fighters had been in the middle of a South American tour which they canceled to come play on his comeback episode. Letterman again handed over the reins of the show to several guest hosts( including Bill Cosby, Brad Garrett, Whoopi Goldberg, Elvis Costello, John McEnroe, Vince Vaughn, Will Ferrell, Bonnie Hunt, Luke Wilson, and bandleader Paul Shaffer) in February 2003, when he was diagnosed with a severe case of shingles. Later that year, Letterman made regular use of guest hosts— including Tom Arnold and Kelsey Grammer— for new shows broadcast on Fridays. In March 2007, Adam Sandler, who had been scheduled to be the lead guest, served as a guest host while Letterman was ill with a stomach virus. Re- signing with CBS. In March 2002, as Letterman' s contract with CBS neared expiration, ABC offered him the time slot for long- running news program" Nightline" with Ted Koppel. Letterman was interested, as he believed he could never match Leno' s ratings at CBS due to Letterman' s complaint of weaker lead- ins from the network' s late local news programs, but was reluctant to replace Koppel. He addressed his decision to re- sign on the air, stating that he was content at CBS and that he had great respect for Koppel. On December 4, 2006, CBS revealed that Letterman signed a new contract to host" Late Show with David Letterman" through the fall of 2010." I' m thrilled to be continuing on at CBS," said Letterman." At my age you really don' t want to have to learn a new commute." Letterman further joked about the subject by pulling up his right pants leg, revealing a tattoo, presumably temporary, of the ABC logo." Thirteen years ago, David Letterman put CBS late night on the map and in the process became one of the defining icons of our network," said Leslie Moonves, president and CEO of CBS Corporation." His presence on our air is an ongoing source of pride, and the creativity and imagination that the" Late Show" puts forth every night is an ongoing display of the highest quality entertainment. We are truly honored that one of the most revered and talented entertainers of our time will continue to call CBS' home.'" According to a 2007 article in" Forbes" magazine, Letterman earned$ 40 million a year. A 2009 article in" The New York Times", however, said his salary was estimated at$ 32 million. In June 2009, Letterman' s Worldwide Pants and CBS reached an agreement to continue the" Late Show" until at least August 2012. The previous contract had been set to expire in 2010, and the two- year extension was shorter than the typical three- year contract period negotiated in the past. Worldwide Pants agreed to lower its fee for the show, though it had remained a" solid moneymaker for CBS" under the previous contract. On the February 3, 2011, edition of the" Late Show", during an interview with Howard Stern, Letterman said he would continue to do his | talk show for" maybe two |
years, I think." In April 2012, CBS announced it had extended its contract with Letterman through 2014. His contract was subsequently extended to 2015. Retirement from" Late Show". During the taping of his show on April 3, 2014, Letterman announced that he had informed CBS president Leslie Moonves that he would retire from hosting" Late Show" by May 20, 2015. Later in his retirement Letterman occasionally stated, in jest, that he had been fired. It was announced soon after that comedian and political satirist Stephen Colbert would succeed Letterman. Letterman' s last episode aired on May 20, 2015, and opened with a presidential sendoff featuring four of the five living American presidents, George H. W. Bush, Bill Clinton, George W. Bush, and Barack Obama, each mimicking the late president Gerald Ford' s statement" Our long national nightmare is over." It also featured cameos from" The Simpsons" and" Wheel of Fortune"( the latter with a puzzle saying" Good riddance to David Letterman"), a Top Ten List of" things I wish I could have said to David Letterman" performed by regular guests including Alec Baldwin, Barbara Walters, Steve Martin, Jerry Seinfeld, Jim Carrey, Chris Rock, Julia Louis- Dreyfus, Peyton Manning, Tina Fey, and Bill Murray, and closed with a montage of scenes from both his CBS and NBC series set to a live performance of" Everlong" by Foo Fighters. The final episode of" Late Show with David Letterman" was watched by 13. 76 million viewers in the United States with an audience share of 9. 3/ 24, earning the show its highest ratings since following the 1994 Winter Olympics on February 25, 1994, and the show' s highest demo numbers( 4. 1 in adults 25– 54 and 3. 1 in adults 18– 49) since Oprah Winfrey' s first" Late Show" appearance following the ending of her feud with Letterman on December 1, 2005. Bill Murray, who had been his first guest on" Late Night", was his final guest on" Late Show". In a rarity for a late- night show, it was also the highest- rated program on network television that night, beating out all prime- time shows. In total, Letterman hosted 6, 080 episodes of" Late Night" and" Late Show", surpassing friend and mentor Johnny Carson as the longest- serving late- night talk show host in U. S. television history. Post-" Late Show". In the months following the end of" Late Show", Letterman was seen occasionally at sports events such as the Indianapolis 500, during which he submitted to an interview with a local publication. He made a surprise appearance on stage in San Antonio, Texas, when he was invited up for an extended segment during Steve Martin' s and Martin Short' s" A Very Stupid Conversation" show, saying" I retired, and... I have no regrets," Letterman told the crowd after walking on stage." I was happy. I' ll make actual friends. I was complacent. I was satisfied. I was content, and then a couple of days ago Donald Trump said he was running for president. I have made the biggest mistake of my | life, ladies and gentlemen" and |
then delivering a Top Ten List roasting Trump' s presidential campaign followed by an onstage conversation with Martin and Short. Cellphone recordings of the appearance were posted on YouTube by audience members and widely reported in the media. In 2016, Letterman joined the climate change documentary show" Years of Living Dangerously" as one of its celebrity correspondents. In season two' s premiere episode, Letterman traveled to India to investigate the country' s efforts to expand its inadequate energy grid, power its booming economy, and bring electricity to 300 million citizens for the first time. He also interviewed Indian Prime Minister Narendra Modi and traveled to rural villages where power is a scarce luxury and explored the United States' role in India' s energy future. On April 7, 2017, Letterman gave the induction speech for the band Pearl Jam into the Rock& amp; Roll Hall Of Fame at a ceremony held at the Barclays Center in Brooklyn, New York City. Also in 2017, Letterman and Alec Baldwin co- hosted" The Essentials" on Turner Classic Movies. Letterman and Baldwin introduced seven films for the series. Netflix. In 2018, Letterman began hosting a six- episode monthly series of hour- long programs on Netflix consisting of long- form interviews and field segments. The show," My Next Guest Needs No Introduction with David Letterman", premiered January 12, 2018, with Barack Obama as its first guest. The second season premiered on May 31, 2019. Season 3 premiered on October 21, 2020, and includes Kim Kardashian West, Robert Downey Jr., Dave Chappelle and Lizzo as guests. Notable exchanges and incidents. NBC and Johnny Carson. In spite of Johnny Carson' s clear intention to pass his title to Letterman, NBC selected Jay Leno to host" The Tonight Show" after Carson' s departure. Letterman maintained a close relationship with Carson through his break with NBC. Three years after he left for CBS, HBO produced a made- for- television movie called" The Late Shift", based on a book by" The New York Times" reporter Bill Carter, chronicling the battle between Letterman and Leno for the" Tonight Show" hosting spot. Carson later made a few cameo appearances as a guest on Letterman' s show. Carson' s final television appearance was on May 13, 1994, on a" Late Show" episode taped in Los Angeles, when he made a surprise appearance during a Top 10 list segment. In early 2005, it was revealed that Carson occasionally sent jokes to Letterman, who used them in his monologue; according to CBS senior vice president Peter Lassally( a onetime producer for both men), Carson got" a big kick out of it." Letterman would do a characteristic Carson golf swing after delivering one of his jokes. In a tribute to Carson, all the opening monologue jokes during the first show after Carson' s death were by Carson. Lassally also claimed that Carson had always believed Letterman, not Leno, to be his" rightful successor". During the early years of the" Late Show" s run, Letterman occasionally used some of Carson' s trademark bits, including" Carnac the Magnificent"( with Paul Shaffer | as Carnac)," Stump the Band", |
and the" Week in Review". Oprah Winfrey. Oprah Winfrey appeared on Letterman' s show when he was hosting NBC' s" Late Night" on May 2, 1989. After that appearance, the two had a 16- year feud that arose, as Winfrey explained to Letterman after it had been resolved, as a result of the acerbic tone of their 1989 interview, of which she said that it" felt so uncomfortable to me that I didn' t want to have that experience again". The feud apparently ended on December 2, 2005, when Winfrey appeared on CBS' s" Late Show with David Letterman" in an event Letterman jokingly called" the Super Bowl of Love". Winfrey and Letterman also appeared together in a" Late Show" promo aired during CBS' s coverage of Super Bowl XLI in February 2007, with the two sitting next to each other on a couch watching the game. Since the game was played between the Indianapolis Colts and Chicago Bears, the Indianapolis- born Letterman wore a Peyton Manning jersey, while Winfrey, whose show was taped in Chicago, wore a Brian Urlacher jersey. On September 10, 2007, Letterman made his first appearance on" The Oprah Winfrey Show" at Madison Square Garden in New York City. Three years later, during CBS' s coverage of Super Bowl XLIV between the Colts and the New Orleans Saints, the two appeared again in a" Late Show" promo, this time with Winfrey sitting on a couch between Letterman and Leno. Letterman wore the retired 70 jersey of Art Donovan, a member of the Colts' Hall of Fame and a regular Letterman guest. The appearance was Letterman' s idea: Leno flew to New York City on an NBC corporate jet, sneaking into the Ed Sullivan Theater during the" Late Show" s February 4 taping wearing a disguise and meeting Winfrey and Letterman at a living room set created in the theater' s balcony, where they taped their promo. Winfrey interviewed Letterman in January 2013 on" Oprah' s Next Chapter". They discussed their feud and Winfrey revealed that she had had a" terrible experience" while appearing on Letterman' s show years earlier. Letterman could not recall the incident but apologized. 2007– 2008 writers' strike." Late Show" went off air for eight weeks in 2007 during November and December because of the Writers Guild of America strike. Letterman' s production company, Worldwide Pants, was the first company to make an individual agreement with the WGA, allowing his show to come back on the air on January 2, 2008. In his first episode back, he surprised the audience with a newly grown beard, which signified solidarity with the strike. His beard was shaved off during the show on January 7, 2008. Palin joke. On June 8 and 9, 2009, Letterman told two sexually themed jokes about a daughter( never named) of Sarah Palin on his TV show. Palin was in New York City at the time with her 14- year- old daughter, Willow, and some contemporaries thought the jokes were aimed at Willow, which caused some controversy. In a statement posted on the | Internet, Palin said," I doubt[ |
Letterman would] ever dare make such comments about anyone else' s daughter" and that" laughter incited by sexually perverted comments made by a 62- year- old male celebrity aimed at a 14- year- old girl is disgusting." On his June 10 show, Letterman responded to the controversy, saying the jokes were meant to be about Palin' s 18- year- old daughter, Bristol, whose pregnancy as an unmarried teenager had caused some controversy during the United States presidential election of 2008." These are not jokes made about[ Palin' s] 14- year- old daughter... I would never, never make jokes about raping or having sex of any description with a 14- year- old girl." His remarks did not end public criticism. The National Organization for Women( NOW) released a statement supporting Palin, noting that Letterman had made"[ only] something of an apology." When the controversy failed to subside, Letterman addressed the issue again on his June 15 show, faulting himself for the error and apologizing" especially to the two daughters involved, Bristol and Willow, and also to the governor and her family and everybody else who was outraged by the joke." Al- Qaeda death threat. On August 17, 2011, it was reported that an Islamist militant had posted a death threat against Letterman on a website frequented by Al- Qaeda supporters, calling on American Muslims to kill him for making a joke about the death of Ilyas Kashmiri, an Al- Qaeda leader who was killed in a June 2011 drone strike in Pakistan. In his August 22 show, Letterman joked about the threat, saying" State Department authorities are looking into this. They' re not taking this lightly. They' re looking into it. They' re questioning, they' re interrogating, there' s an electronic trail— but everybody knows it' s Leno." Appearances in other media. Letterman appeared in the pilot episode of the short- lived 1986 series" Coach Toast", and appears with a bag over his head as a guest on Bonnie Hunt's1990s sitcom" The Building". He appeared in" The Simpsons" as himself in a couch gag when the Simpsons find themselves( and the couch) in" Late Night with David Letterman". He had a cameo in the feature film" Cabin Boy", with Chris Elliott, who worked as a writer for Letterman. In this and other appearances, Letterman is listed in the credits as" Earl Hofert", the name of Letterman' s maternal grandfather. He also appeared as himself in the Howard Stern biographical film" Private Parts" and the 1999 Andy Kaufman biopic" Man on the Moon", in a few episodes of Garry Shandling's1990s TV series" The Larry Sanders Show", and in" The Abstinence", a 1996 episode of the sitcom" Seinfeld". Letterman provided vocals for the Warren Zevon song" Hit Somebody" from" My Ride' s Here", and provided the voice for Butt- head' s father in the 1996 animated film" Beavis and Butt- Head Do America", again credited as Earl Hofert. Letterman was the focus of" The Avengers on" Late Night with David Letterman"", issue 239( January 1984) of the Marvel comic book series" The Avengers", in which | the title characters( specifically Hawkeye, |
Wonder Man, Black Widow, Beast, and Black Panther) are guests on" Late Night". A parody of Letterman named David Endochrine is gassed to death along with his bandleader, Paul, and their audience in Frank Miller' s" The Dark Knight Returns". In"", Letterman was parodied as" David Litterbin". Letterman appears in issues 13– 14 and 18 of Harvey Pekar' s autobiographical comic book" American Splendor". Those issues show Pekar' s accounts of appearances on" Late Night". In 2010, a documentary directed by Joke Fincioen and Biagio Messina," Dying to do Letterman", was released, featuring Steve Mazan, a standup comic, who has cancer and wants to appear on Letterman' s show. The film won best documentary and jury awards at the Cinequest Film Festival. Mazan published a book of the same name( full title" Dying to Do Letterman: Turning Someday into Today") about his own saga. Letterman appeared as a guest on CNN' s" Piers Morgan Tonight" on May 29, 2012, when he was interviewed by Regis Philbin, the guest host and Letterman' s longtime friend. Philbin again interviewed Letterman( and Shaffer) while guest- hosting CBS' s" The Late Late Show"( between the tenures of Craig Ferguson and James Corden) on January 27, 2015. In June 2013, Letterman appeared in the second episode of season two of" Comedians in Cars Getting Coffee". On November 5, 2013, he and Bruce McCall published a fiction satire book," This Land Was Made for You and Me( But Mostly Me)",. In Week 13 of the 2021 NFL season,LettermanjoinedPeytonandEliManningontheirESPN2 feed of the" Monday Night Football" game between the New England Patriots and Buffalo Bills. Letterman mocked Bill Belichick after he was caught on camera wiping his nose with his shirt and was in the middle of recalling being with Roger Goodell when Goodell was booed at the unveiling of Peyton Manning' s statue in Indianapolis when ESPN suddenly cut to commercials. On January 25, 2022, current" Late Night" host Seth Meyers announced that Letterman would be the guest on the February 1 show,markingthe40th anniversary of the franchise' s debut. Business ventures. Letterman started his production company, Worldwide Pants Incorporated, which produced his show and several others, in 1991. The company also produces feature films and documentaries and founded its own record label, Clear Entertainment. Worldwide Pants received significant attention in December 2007 after it was announced that it had independently negotiated its own contract with the Writers Guild of America, East, thus allowing Letterman, Craig Ferguson, and their writers to return to work, while the union continued its strike against production companies, networks, and studios with whom it had not yet reached agreements. Letterman, Bobby Rahal, and Mike Lanigan co- own Rahal Letterman Lanigan Racing, an auto racing team competing in the WeatherTech SportsCar Championship and NTT IndyCar series. The team has twice won the Indianapolis 500: in 2004 with driver Buddy Rice, and in 2020 with Takuma Sato. The Letterman Foundation for Courtesy and Grooming is a private foundation through which Letterman has donated millions of dollars to charities and other nonprofit organizations in Indiana and Montana, celebrity- | affiliated organizations such as Paul |
Newman' s Hole in the Wall Gang Camp, Ball State University, the American Cancer Society, the Salvation Army, and" Médecins Sans Frontières". Influences. Letterman' s biggest influence and mentor was Johnny Carson. Other comedians who influenced Letterman were Paul Dixon, Steve Allen, Jonathan Winters, Garry Moore, Jack Paar, Don Rickles, and David Brenner. Although Ernie Kovacs has also been mentioned as an influence, Letterman has denied this. Comedians influenced by Letterman include Conan O' Brien, Jon Stewart, Stephen Colbert, Ray Romano, Jimmy Kimmel, Jay Leno, Arsenio Hall, Larry Wilmore, Seth Meyers, Norm Macdonald, Jimmy Fallon, John Oliver, and James Corden. Personal life. Letterman suffers from tinnitus, a symptom of hearing loss. On the" Late Show" in 1996, he talked about his experience with tinnitus during an interview with William Shatner, who has severe tinnitus caused by an on- set explosion. Letterman has said that he was initially unable to pinpoint the noise inside his head and that he hears a constant ringing in his ears. Letterman no longer drinks alcohol. On more than one occasion, he said that he had once been a" horrible alcoholic" and had begun drinking around the age of 13 and continued until 1981 when he was 34. He has said that in 1981," I was drunk 80% of the time... I loved it. I was one of those guys, I looked around, and everyone else had stopped drinking and I couldn' t understand why." When he was shown drinking what appears to be alcohol on" Late Night" or the" Late Show", it was actually apple juice. In 2015, Letterman said of his anxiety:" For years and years and years— 30, 40 years— I was anxious and hypochondriacal and an alcoholic, and many, many other things that made me different from other people." He became calmer through a combination of Transcendental Meditation and low doses of medication. Letterman is a Presbyterian, a religious tradition he was originally brought up in by his mother, though he once said he was motivated by" Lutheran, Midwestern guilt". Marriages, relationships, and family. On July 2, 1968, Letterman married his college sweetheart, Michelle Cook, in Muncie, Indiana; they divorced by October 1977. He also had a long- term cohabiting relationship with the former head writer and producer on" Late Night", Merrill Markoe, from 1978 to 1988. Markoe created several" Late Night" staples, such as" Stupid Pet/ Human Tricks"." Time" magazine wrote that theirs was the defining relationship of Letterman' s career, with Markoe also acting as his writing partner. She" put the surrealism in Letterman' s comedy." Letterman and Regina Lasko started dating in February 1986, while he was still living with Markoe. Lasko gave birth to their son, Harry Joseph Letterman, on November 3, 2003. Harry is named after Letterman' s father. In 2005, police discovered a plot to kidnap Letterman' s son and demand a$ 5 million ransom. Kelly Frank, a house painter who had worked for Letterman, was charged in the conspiracy. Letterman and Lasko wed on March 19, 2009, in a quiet courthouse civil ceremony in Choteau, Montana, where | he had purchased a ranch |
in 1999. Letterman announced the marriage during the taping of his show of March 23, shortly after congratulating Bruce Willis on his marriage the week before. Letterman told the audience he nearly missed the ceremony because his truck became stuck in mud two miles from their house. The family resides in North Salem, New York, on a estate. Extortion attempt and revelation of affairs. On October 1, 2009, Letterman announced on his show that he had been the victim of a blackmail attempt by a person threatening to reveal his sexual relationships with several of his female employees— a fact Letterman immediately thereafter confirmed. He said that someone had left a package in his car with material he said he would write into a screenplay and a book if Letterman did not pay him$ 2 million. Letterman said that he contacted the Manhattan District Attorney' s office and partook in a sting operation that involved the handover of a fake check to the extortionist. Joe Halderman, a producer of the CBS news magazine television series" 48 Hours", was arrested around noon( EST) on October 1, 2009, after trying to deposit the check. He was indicted by a Manhattan grand jury following testimony from Letterman and pleaded not guilty to a charge of attempted grand larceny on October 2, 2009. Halderman pleaded guilty in March 2010 and was sentenced to six months in prison, followed by probation and community service. A central figure in the case and one of the women with whom Letterman had had a sexual relationship was his longtime personal assistant Stephanie Birkitt, who often appeared on the show. She had also worked for" 48 Hours". Until a month before the revelations, she had shared a residence with Halderman, who allegedly had copied her personal diary and used it, along with private emails, in the blackmail package. In the days following the initial announcement of the affairs and the arrest, several prominent women, including Kathie Lee Gifford, co- host of NBC' s" Today Show", and NBC news anchor Ann Curry, questioned whether Letterman' s affairs with subordinates created an unfair working environment. A spokesman for Worldwide Pants said that the company' s sexual harassment policy did not prohibit sexual relationships between managers and employees. According to business news reporter Eve Tahmincioglu," CBS suppliers are supposed to follow the company' s business conduct policies" and the CBS 2008 Business Conduct Statement states that" If a consenting romantic or sexual relationship between a supervisor and a direct or indirect subordinate should develop, CBS requires the supervisor to disclose this information to his or her Company' s Human Resources Department". On October 3, 2009, a former CBS employee, Holly Hester, announced that she and Letterman had engaged in a yearlong secret affairintheearly1990s while she was his intern and a student at New York University. On October 5, 2009, Letterman devoted a segment of his show to a public apology to his wife and staff. Three days later, Worldwide Pants announced that Birkitt had been placed on a" paid leave of absence" from the" | Late Show". On October 15, |
CBS News announced that the company' s chief investigative correspondent, Armen Keteyian, had been assigned to conduct an" in- depth investigation" into Letterman. Stalkers. Beginning in May 1988, Letterman was stalked by Margaret Mary Ray, a woman suffering from schizophrenia. She stole his Porsche, camped out on his tennis court, and repeatedly broke into his house. Her exploits drew national attention, with Letterman occasionally joking about her on his show, though he never named her. After she killed herself at age 46 in October 1998, Letterman told" The New York Times" that he had great compassion for her. A spokesperson for Letterman said:" This is a sad ending to a confused life." In 2005 another person was able to obtain a restraining order from a New Mexico judge, prohibiting Letterman from contacting her. She claimed he had sent her coded messages via his television program, causing her bankruptcy and emotional distress. Law professor Eugene Volokh called the case" patently frivolous". Interests. Letterman is a car enthusiast and owns an extensive collection. In 2012, it was reported that the collection consisted of ten Ferraris, eight Porsches, four Austin- Healeys, two Honda motorcycles, a Chevy pickup, and one car each from automakers Mercedes- Benz, Jaguar, MG, Volvo, and Pontiac. In his 2013 appearance on" Comedians in Cars Getting Coffee", part of Jerry Seinfeld' s conversation with Letterman was filmed in Letterman' s 1995 Volvo 960 station wagon, which is powered by a 380- horsepower racing engine. Paul Newman had the car built for Letterman. Letterman shares a close relationship with the rock and roll band Foo Fighters since its appearance on his first show upon his return from heart surgery. The band appeared many times on the" Late Show", including a week- long stint in October 2014. While introducing the band' s performance of" Miracle" on the show of October 17, 2014, Letterman told the story of how a souvenir video of himself and his four- year- old son learning to ski used the song as background music, unbeknownst to Letterman until he saw it. He stated:" This is the second song of theirs that will always have great, great meaning for me for the rest of my life". This was the first time the band had heard this story. Worldwide Pants co- produced Dave Grohl' s"" TV series." Letterman was the first person to get behind this project," Grohl said. Awards, honors and legacy. David Letterman Communication and Media BuildingOn September 7, 2007, Letterman visited his" alma mater", Ball State University in Muncie, Indiana, for the dedication of a communications facility named in his honor for his dedication to the university. The$ 21 million, David Letterman Communication and Media Building opened for the 2007 fall semester. Thousands of Ball State students, faculty, and local residents welcomed Letterman back to Indiana. Letterman' s emotional speech touched on his struggles as a college student and his late father, and also included the" top ten good things about having your name on a building", finishing with" if reasonable people can put my name on a$ 21 | million building, anything is possible." |
Over many years Letterman" has provided substantial assistance to[ Ball State' s] Department of Telecommunications, including an annual scholarship that bears his name." At the same time, Indiana Governor Mitch Daniels gave Letterman a Sagamore of the Wabash award, which recognizes distinguished service to the state of Indiana. Awards and nominationsIn his capacities as either a performer, producer, or as part of a writing team, Letterman is among the most nominated people in the history of the Emmy Awards, with 52 nominations, winning two Daytime Emmys and ten Primetime Emmys since 1981. He won four American Comedy Awards and in 2011 became the first recipient of the Johnny Carson Award for Comedic Excellence at The Comedy Awards. Letterman was a recipient of the 2012 Kennedy Center Honors, where he was called" one of the most influential personalities in the history of television, entertaining an entire generation of late- night viewers with his unconventional wit and charm." On May 16, 2017, Letterman was named the next recipient of the Mark Twain Prize for American Humor, the award granted annually by the John F. Kennedy Center for the Performing Arts. He received the prize in a ceremony on October 22, 2017. Delroy George Lindo( born 18 November 1952) is a British- American actor. He is the recipient of such accolades as a NAACP Image Award, a Satellite Award, and nominations for a Drama Desk Award, a Helen Hayes Award, a Tony Award, two Critics' Choice Television Awards, and three Screen Actors Guild Awards. Lindo has played prominent roles in four Spike Lee films: West Indian Archie in" Malcolm X"( 1992), Woody Carmichael in" Crooklyn"( 1994), Rodney Little in" Clockers"( 1995), and Paul in" Da 5 Bloods"( 2020); he received universal acclaim for his performance in" Da 5 Bloods" as a Vietnam War veteran, winning the New York Film Critics Circle Award for Best Actor and the National Society of Film Critics Award for Best Actor. Lindo also played Bo Catlett in" Get Shorty"( 1995), Arthur Rose in" The Cider House Rules"( 1999), and Detective Castlebeck in" Gone in 60 Seconds"( 2000). Lindo starred as Alderman Ronin Gibbons in the TV series" The Chicago Code"( 2011), as Winter on the series" Believe"( 2014), and as Adrian Boseman in" The Good Fight"( 2017– 2021). Early life. Delroy Lindo was born in 1952 in Lewisham, south- east London, the son of Jamaican parents. His mother had immigrated to the UK in 1951 from Jamaica to work as a nurse, and his father worked in various jobs. Lindo grew up in nearby Eltham. He became interested in acting as a child when he appeared in a nativity play at school. As a teenager, Lindo and his mother moved to Toronto, Ontario. When he was 16, they moved to San Francisco. At the age of 24, Lindo began his studies in acting at the American Conservatory Theater, graduating in 1979. Career. Lindo' s film debut came in 1976 with the Canadian John Candy comedy" Find the Lady", followed by two other roles in films, including an army sergeant in" | More American Graffiti"( 1979). He |
stopped his film career for 10 years to concentrate on theatre acting. In 1982 he debuted on Broadway in"" Master Harold"... and the Boys," directed by the play' s South African author Athol Fugard. By 1988, Lindo had earned a Tony nomination for his portrayal of Herald Loomis in August Wilson' s" Joe Turner' s Come and Gone". Lindo returned to film in the science fiction film" Salute of the Jugger"( 1990), which has become a cult classic. Although he had turned down Spike Lee for a role in" Do the Right Thing", Lee cast him as Woody Carmichael in the drama" Crooklyn"( 1994), which brought Lindo notice. His other roles with Lee include the West Indian Archie, a psychotic gangster, in" Malcolm X" and a starring role as a neighborhood drug dealer in" Clockers". Other films in which he has starring roles are Barry Sonnenfeld' s" Get Shorty"( 1995), Ron Howard' s" Ransom"( 1996) and" Soul of the Game"( 1996), as the baseball player Satchel Paige. In 1998 Lindo co- starred as African- American explorer Matthew Henson, in the TV film" Glory& amp; Honor", directed by Kevin Hooks. It portrayed his nearly 20- year partnership with Commander Robert Peary in Arctic exploration and their effort to find the Geographic North Pole in 1909. He received a Satellite Award for best actor. Lindo has continued to work in television, and in 2006 was seen on the short- lived drama" Kidnapped". Lindo had a small role in the 1995 film" Congo", playing the corrupt Captain Wanta. Lindo was not credited for the role. He played an angel in the comedy film" A Life Less Ordinary"( 1997). He guest- starred on" The Simpsons" in the episode" Brawl in the Family", playing a character named Gabriel. In the British film" Wondrous Oblivion"( 2003), directed by Paul Morrison, Lindo starred as Dennis Samuels, the father of aJamaicanimmigrantfamilyinLondoninthe1950s. Lindo said he made the film in honor of his parents, who had similarly moved to London in those years. In 2007, Lindo began an association with Berkeley Repertory Theatre in Berkeley, California, when he directed Tanya Barfield' s play" The Blue Door". In the autumn of 2008, Lindo revisited August Wilson' s play" Joe Turner' s Come and Gone", directing a production at the Berkeley Rep. In 2010, he played the role of elderly seer Bynum in David Lan' s production of" Joe Turner" at the Young Vic Theatre in London. Lindo was in the main cast of the Fox crime drama" The Chicago Code"( 2011), the NBC fantasy series" Believe", and the ABC soap" Blood& amp; Oil"( 2015). In 2017, Lindo began playing Adrian Boseman in the CBS legal drama" The Good Fight", a role he would star in for the series' first four seasons and reprise as a guest star in its fifth season. Lindo appeared in the action film" Point Break"( 2015), the horror film" Malicious"( 2018), the drama" Battlecreek"," Da 5 Bloods"( 2020), another collaboration with Spike Lee, and" The Harder They Fall"( 2021) as Bass Reeves. For his role in" Da 5 Bloods", | Lindo received critical acclaim and |
a number of accolades. In development. In 2015, Lindo was expected to play Marcus Garvey in a biopic of the black nationalist historical figure that had been in pre- production for several years. Lindo was cast as the lead in an ABC drama pilot" Harlem' s Kitchen" in March 2020. It was announced in July 2021 that Lindo would star as Mr Nancy in the British Amazon Prime miniseries adaptation of Neil Gaiman' s" Anansi Boys" alongside Malachi Kirby. In November, Lindo officially joined the cast of the upcoming Marvel film" Blade" in an undisclosed role. Personal life. Lindo married his wife Neshormeh Lindo in 1990. They settled down in Oakland, California, in 1996, having moved from New York City and preferring the San Francisco Bay Area to Los Angeles. Their son Damiri was born in 2001. In 2014, Lindo graduated with a master' s degree in fine arts from New York University' s Gallatin School. In addition, he was awarded an honorary doctorate in Arts and Humanities from Virginia Union University. Lindo is a supporter of Manchester United F. C. David Janssen( born David Harold Meyer)( March 27,1931February 13, 1980) was an American film and television actor who is best known for his starring role as Richard Kimble in the television series" The Fugitive"( 1963– 1967). Janssen also had the title roles in three other series:" Richard Diamond, Private Detective";" Harry O"; and" O' Hara, U. S. Treasury". In 1996" TV Guide" ranked him number 36 on its" 50 Greatest TV Stars of All Time" list. Early life. David Janssen was born on March 27, 1931, in Naponee, a village in Franklin County in southern Nebraska, to Harold Edward Meyer, a banker and Berniece Graf. Following his parents' divorce in 1935, his mother moved with five- year- old David to Los Angeles, California, and later married Eugene Janssen in 1940 in Los Angeles. Young David used his stepfather' s name after he entered show business as a child. He attended Fairfax High School in Los Angeles, where he excelled on the basketball court, setting a school scoring record that lasted over 20 years. His first film part was at the age of thirteen, and by the age of twenty- five he had appeared in twenty films and served two years as an enlisted man in the United States Army. During his Army days, Janssen became friends with fellow enlistees Martin Milner and Clint Eastwood while posted at Fort Ord, California. Acting career. Janssen appeared in many television series before he landed programs of his own. In 1956, he and Peter Breck appeared in John Bromfield' s syndicated series" Sheriff of Cochise" in the episode" The Turkey Farmers". Later, he guest- starred on NBC' s medical drama" The Eleventh Hour" in the role of Hal Kincaid in the 1962 episode" Make Me a Place", with series co- stars Wendell Corey and Jack Ging. He joined friend Martin Milner in a 1962 episode of" Route 66" as the character Kamo in the episode" One Tiger to a Hill." Janssen starred in four television | series of his own: At |
the time, the final episode of" The Fugitive" held the record for the greatest number of American homes with television sets to watch a series finale, at 72 percent in August 1967. His films include" To Hell and Back", the biography of Audie Murphy, who was the most decorated American soldier of World War II;" Hell to Eternity", a 1960 American World War II biopic starring Jeffrey Hunter, a Hispanic boy who fought in the Battle of Saipan and was raised by Japanese American foster parents; John Wayne' s Vietnam war film" The Green Berets"; opposite Gregory Peck in the space story" Marooned", in which Janssen played an astronaut sent to rescue three stranded men in space, and" The Shoes of the Fisherman", as a television journalist in Rome reporting on the election of a new Pope( Anthony Quinn). He also played pilot Harry Walker in the 1973 action movie" Birds of Prey". He starred as a Los Angeles police detective trying to clear himself in the killing of an apparently innocent doctor in the 1967 film" Warning Shot". The film was shot during a break in the spring and summer of 1966 between the third and fourth seasons of" The Fugitive." Janssen played an alcoholic in the 1977 TV movie" A Sensitive, Passionate Man", which co- starred Angie Dickinson, as an engineer who devises an unbeatable system for blackjack in the 1978 made- for- TV movie" Nowhere to Run", co- starring Stefanie Powers and Linda Evans. Janssen' s impressively husky voice was used to good effect as the narrator for the TV mini- series" Centennial"( 1978– 79); he also appeared in the final episode. He starred in the made- for- TV mini series" S. O. S. Titanic" as John Jacob Astor, playing opposite Beverly Ross as his wife, Madeleine, in 1979. Though Janssen' s scenes were cut from the final release, he also appeared as a journalist in the film" Inchon", which he accepted to work with Laurence Olivier who played General Douglas MacArthur. At the time of his death, Janssen had just begun filming a television movie playing the part of Father Damien, the priest who dedicated himself to the leper colony on the island of Molokai, Hawaii. The part was eventually reassigned to actor Ken Howard of the CBS series" The White Shadow". In 1996" TV Guide" ranked" The Fugitive" number 36 on its' 50 Greatest Shows of All Time' list. Personal life. Janssen was married twice. His first marriage was to model and interior decorator Ellie Graham, whom he married in Las Vegas on August 25, 1958. They divorced in 1968. In 1975, he married actress and model Dani Crayne Greco. They remained married until Janssen' s death. Death. David Janssen died of a sudden heart attack in the early morning of February 13, 1980, at his home in Malibu, California, at the age of 48. At the time of his death, Janssen was filming the television movie" Father Damien". Janssen was buried at the Hillside Memorial Park Cemetery in Culver City, California. A non- denominational funeral was | held at the Jewish chapel |
of the cemetery on February 17. Suzanne Pleshette delivered the eulogy at the request of Janssen' s widow. Milton Berle, Johnny Carson, Tommy Gallagher, Richard Harris, Stan Herman, Rod Stewart and Gregory Peck were among Janssen' s pallbearers. Honorary pallbearers included Jack Lemmon, George Peppard, James Stewart and Danny Thomas. According to friend and" Fugitive" co- star Barry Morse," David Janssen was well known as one of the hardest working actors in the USA", regularly working 12- 14 hours a day, and he kept working until his early death. For his contribution to the television industry, David Janssen has a star on the Hollywood Walk of Fame located on the 7700 block of Hollywood Boulevard. In the history of Christianity, docetism( from the" dokeĩn"" to seem"," dókēsis"" apparition, phantom") is the heterodox doctrine that the phenomenon of Jesus, his historical and bodily existence, and above all the human form of Jesus, was mere semblance without any true reality. Broadly it is taken as the belief that Jesus only seemed to be human, and that his human form was an illusion. The word" Dokētaí"(" Illusionists") referring to early groups who denied Jesus' s humanity, first occurred in a letter by Bishop Serapion of Antioch( 197– 203), who discovered the doctrine in the Gospel of Peter, during a pastoral visit to a Christian community using it in Rhosus, and later condemned it as a forgery. It appears to have arisen over theological contentions concerning the meaning, figurative or literal, of a sentence from the Gospel of John:" the Word was made Flesh". Docetism was unequivocally rejected at the First Council of Nicaea in 325 and is regarded as heretical by the Catholic Church, Eastern Orthodox Church, Coptic Orthodox Church of Alexandria, Orthodox Tewahedo, and many Protestant denominations that accept and hold to the statements of these early church councils, such as Reformed Baptists, Reformed Christians, and all Trinitarian Christians. Definitions. Docetism is broadly defined as any teaching that claims that Jesus' body was either absent or illusory. The term' docetic' is rather nebulous. Two varieties were widely known. In one version, as in Marcionism, Christ was so divine that he could not have been human, since God lacked a material body, which therefore could not physically suffer. Jesus only" appeared" to be a flesh- and- blood man; his body was a phantasm. Other groups who were accused of docetism held that Jesus was a man in the flesh, but Christ was a separate entity who entered Jesus' body in the form of a dove at his baptism, empowered him to perform miracles, and abandoned him upon his death on the cross. Christology and theological implications. Docetism' s origin within Christianity is obscure. Ernst Käsemann controversially defined the Christology of the Gospel of John as" naïve docetism" in 1968. The ensuing debate reached an impasse as awareness grew that the very term" docetism", like" gnosticism", was difficult to define within the religio- historical framework of the debate. It has occasionally been argued that its origins were in heterodox Judaism or Oriental and Grecian philosophies. The | alleged connection with Jewish Christianity |
would have reflected Jewish Christian concerns with the inviolability of( Jewish) monotheism. Docetic opinions seem to have circulated from very early times, 1 John 4: 2 appearing explicitly to reject them.Some1stcentury Christian groups developed docetic interpretations partly as a way to make Christian teachings more acceptable to pagan ways of thinking about divinity. In his critique of the theology of Clement of Alexandria, Photius in his Myriobiblon held that Clement' s views reflected a quasi- docetic view of the nature of Christ, writing that"[ Clement] hallucinates that the Word was not incarnate but" only seems to be"."( ὀνειροπολεῖ καὶ μὴ σαρκωθῆναι τὸν λόγον ἀλλὰ" δόξαι".) In Clement' s time, some disputes contended over whether Christ assumed the" psychic" flesh of mankind as heirs to Adam, or the" spiritual" flesh of the resurrection. Docetism largely died out during the first millennium AD. The opponents against whom Ignatius of Antioch inveighs are often taken to be Monophysite docetists. In his letter to the Smyrnaeans, 7: 1,writtenaround110AD, he writes: While these characteristics fit a Monophysite framework, a slight majority of scholars consider that Ignatius was waging a polemic on two distinct fronts, one Jewish, the other docetic; a minority holds that he was concerned with a group that commingled Judaism and docetism. Others, however, doubt that there was actual docetism threatening the churches, arguing that he was merely criticizing Christians who lived Jewishly or that his critical remarks were directed at an Ebionite or Cerinthian possessionist Christology, according to which Christ was a heavenly spirit that temporarily possessed Jesus. Islam and docetism. Some commentators have attempted to make a connection between Islam and docetism using the following Quranic verse: Some scholars accept that Islam was influenced by Manichaeism( Docetism) in this view.HoweverthegeneralconsensusisthatManichaeismwasnotprevalentinMeccainthe6thand7th centuries, when Islam developed. Docetism and Christ myth theory. Since Arthur Drews published his" The Christ Myth"(" Die Christusmythe") in 1909, occasional connections have been drawn between docetist theories and the modern idea that Christ was a myth. Shailer Mathews called Drews' theory a" modern docetism". Frederick Cornwallis Conybeare thought any connection to be based on a misunderstanding of docetism. The idea recurred in classicist Michael Grant' s 1977 review of the evidence for Jesus, who compared modern scepticism about a historical Jesus to the ancient docetic idea that Jesus only" seemed" to come into the world" in the flesh". Modern supporters of the theory did away with" seeming". Such theorems are rejected by modern scholarship, which considers the Christ myth theory a fringe theory, which is generally not taken seriously. The drachma(,; pl." drachmae" or" drachmas") was the currency used in Greece during several periods in its history: It was also a small unit of weight. Ancient drachma. The name" drachma" is derived from the verb(,"( I) grasp"). It is believed that the same word with the meaning of" handful" or" handle" is found in Linear B tablets of the Mycenean Pylos. Initially a drachma was a fistful( a" grasp") of six" oboloí" or" obeloí"( metal sticks, literally" spits") used as a form of currency as early as 1100 BC and being | a form of" bullion": bronze, |
copper, or iron ingots denominated by weight. A hoard of over 150 rod- shaped obeloi was uncovered at Heraion of Argos in Peloponnese. Six of them are displayed at the Numismatic Museum of Athens. It was the standard unit of silver coinage at most ancient Greek mints, and the name" obol" was used to describe a coin that was one- sixth of a drachma. The notion that" drachma" derived from the word for fistful was recorded by Herakleides of Pontos( 387– 312 BC) who was informed by the priests of Heraion that Pheidon, king of Argos, dedicated rod- shaped obeloi to Heraion. Similar information about Pheidon' s obeloi was also recorded at the Parian Chronicle. Ancient Greek coins normally had distinctive names in daily use. The Athenian tetradrachm was called owl, the Aeginetic stater was called chelone, the Corinthian stater was called" hippos"( horse) and so on. Each city would mint its own and have them stamped with recognizable symbols of the city, known as badge in numismatics, along with suitable inscriptions, and they would often be referred to either by the name of the city or of the image depicted. The exact exchange value of each was determined by the quantity and quality of the metal, which reflected on the reputation of each mint. Among the Greek cities that used the drachma were: Abdera, Abydos, Alexandria, Aetna, Antioch, Athens, Chios, Cyzicus, Corinth, Ephesus, Eretria, Gela, Catana, Kos, Maronia, Naxos, Pella, Pergamum, Rhegion, Salamis, Smyrni, Sparta, Syracuse, Tarsus, Thasos, Tenedos, Troy and more.The5th century BC Athenian tetradrachm(" four drachmae") coin was perhaps the most widely used coin in the Greek world prior to the time of Alexander the Great( along with the Corinthian stater). It featured the helmeted profile bust of Athena on the obverse( front) and an owl on the reverse( back). In daily use they were called" glaukes"( owls), hence the proverb,' an owl to Athens', referring to something that was in plentiful supply, like' coals to Newcastle'. The reverse is featured on the national side of the modern Greek 1 euro coin. Drachmae were minted on different weight standards at different Greek mints. The standard that came to be most commonly used was the Athenian or Attic one, which weighed a little over 4. 3 grams. After Alexander' s conquests, the name" drachma" was used in many of the Hellenistic kingdoms in the Middle East, including the Ptolemaic kingdom in Alexandria and the Parthian Empire based in what is modern- day Iran. The Arabic unit of currency known as" dirham"(), known from pre- Islamic times and afterwards, inherited its name from the drachma or didrachm(, 2 drachmae); the dirham is still the name of the official currencies of Morocco and the United Arab Emirates. The Armenian dram() also derives its name from the drachma. Value. It is difficult to estimate comparative exchange rates with modern currency because the range of products produced by economies of centuries gone by were different from today, which makes purchasing power parity( PPP) calculations very difficult; however, some historians and economists have estimated that | in the5th century BC a |
drachma had a rough value of 25 U. S. dollars( in the year 1990– equivalent to US$ 46. 50 in 2015), whereas classical historians regularly say that in the heyday of ancient Greece( the fifth and fourth centuries) the daily wage for a skilled worker or a hoplite was one drachma, and for a heliast( juror) half a drachma since 425 BC. Modern commentators derived from Xenophon that half a drachma per day( 360 days per year) would provide" a comfortable subsistence" for" the poor citizens"( for the head of a household in 355 BC). Earlier in 422 BC, we also see in Aristophanes(" Wasps", line 300– 302) that the daily half- drachma of a juror is just enough for the daily subsistence of a family of three. A modern person might think of one drachma as the rough equivalent of a skilled worker' s daily pay in the place where they live, which could be as low as US$ 1, or as high as$ 100, depending on the country. Fractions and multiples of the drachma were minted by many states, most notably in Ptolemaic Egypt, which minted large coins in gold, silver and bronze. Notable Ptolemaic coins included the gold" pentadrachm" and" octadrachm", and silver" tetradrachm"," decadrachm" and" pentakaidecadrachm". This was especially noteworthy as it would not be until the introduction of the Guldengroschen in 1486 that coins of substantial size( particularly in silver) would be minted in significant quantities. For the Roman successors of the drachma, see Roman provincial coins. Denominations of ancient Greek drachma. The weight of the silver drachma was approximately 4. 3 grams or 0. 15 ounces, although weights varied significantly from one city- state to another. It was divided into six obols of 0. 72 grams, which were subdivided into four tetartemoria of 0. 18 grams, one of the smallest coins ever struck, approximately 5– 7 mm in diameter. Historic currency divisions. Minae and talents were never actually minted: they represented weight measures used for commodities( e. g. grain) as well as metals like silver or gold. The New Testament mentions both didrachma and, by implication, tetradrachma in context of the Temple tax. Luke' s Gospel includes a parable told by Jesus of a woman with 10 drachmae, who lost one and searched her home until she found it. Modern drachma. First modern drachma. The drachma was reintroduced in May 1832, shortly before the establishment of the modern state of Greece( with the exception of the subdivision Taurus). It replaced the" phoenix" at par. The drachma was subdivided into 100 lepta. Coins. The first coinage consisted ofcopperdenominationsof1λ,2λ,5λand10λ, silver denominations of₯,₯,₯ 1 and₯ 5 and a gold coin of₯ 20. The drachma coin weighed 4. 5 g and contained 90% silver, with the₯ 20 coin containing 5. 8 g of gold. In 1868, Greece joined the Latin Monetary Union and the drachma became equal in weight and value to the French franc. The new coinage issued consisted of copper coins of1λ,2λ,5λ and10λ, with the5λ and10λ coins bearing the names" obolos"() and" diobolon"(), respectively; silver coins of20λ and50λ,₯ | 1,₯ 2 and₯ 5 and |
gold coins of₯ 5,₯ 10 and₯ 20.( Very small numbers of₯ 50 and₯ 100 coins in gold were also issued.) In 1894, cupro-nickel5λ,10λand20λ coins were introduced.No1λor2λcoinhadbeenissuedsincethelate1870s. Silver coins of₯ 1 and₯ 2 were last issued in 1911, and no coins were issued between 1912 and 1922, during which time the Latin Monetary Union collapsed due to World War I. Between 1926 and 1930, a new coinage was introduced for the new Hellenic Republic, consisting of cupro-nickelcoinsindenominationsof20λ,50λ,₯ 1, and₯ 2; nickel coins of₯ 5; and silver coins of₯ 10 and₯ 20. These were the last coins issued for the first modern drachma, none were issued for the second. Notes. Notes were issued by the National Bank of Greece from 1841 until 1928. The Bank of Greece issued notes from 1928 until 2001, when Greece joined the Euro. Early denominations ranged from₯ 10 to₯ 500. Smaller denominations(₯ 1,₯ 2,₯ 3 and₯ 5) were issued from 1885, with the first₯ 5 notes being made by cutting₯ 10 notes in half. When Greece finally achieved its independence from the Ottoman Empire in 1828, the phoenix was introduced as the monetary unit; its use was short- lived, however, and in 1832 the phoenix was replaced by the drachma, adorned with the image of King Otto of Greece, who reigned as modern Greece' s first king from 1832 to 1862. The drachma was divided into 100 lepta. In 2002 the drachma ceased to be legal tender after the euro, the monetary unit of the European Union, became Greece' s sole currency. From 1917 to 1920, the Greek government took control of issuing small change notes under Law 991/ 1917. During that time, the government issued denominations of 10& amp; 50 lepta, and₯ 1,₯ 2& amp;₯ 5. The National Bank of Greece introduced₯ 1, 000 notes in 1901, and the Bank of Greece introduced₯ 5, 000 notes in 1928.Theeconomicdepressionofthe1920s affected many nations around the globe, including Greece. In 1922, the Greek government issued a forced loan in order to finance their growing budget deficit. On 1 April 1922, the government decreed that half of all bank notes had to be surrendered and exchanged for 6. 5% bonds. The notes were then cut in half, with the portion bearing the Greek crown standing in for the bonds while the other half was exchanged for a new issue of central bank notes at half the original value. The Greek government again issued notes between 1940 and 1944, in denominations ranging from 50 lepta to 20. During the German– Italian occupation of Greece from 1941 to 1944, catastrophic hyperinflation caused much higher denominations to be issued, culminating in₯ 100, 000, 000, 000 notes in 1944. The Italian occupation authorities in the Ionian Islands printed their own currency, the Ionian drachma. Second modern drachma. On 11 November 1944, following the liberation of Greece from Nazi Germany, old drachma were exchanged for new ones at the rate of₯ 50, 000, 000, 000 to₯ 1. Only paper money was issued for the second drachma. The government issued notes of₯ 1,₯ 5,₯ 10 and₯ 20, with | the Bank of Greece issuing₯ |
50,₯ 100,₯ 500,₯ 1, 000,₯ 5, 000, and₯ 10, 000 notes. This drachma also suffered from high inflation. The government later issued₯ 100,₯ 500, and₯ 1, 000- drachma notes, and the Bank of Greece issued₯ 20, 000 and₯ 50, 000 notes. Third modern drachma. On 9 April 1953, in an effort to halt inflation, Greece joined the Bretton Woods system. On 1 May 1954, the drachma was revalued at a rate of₯ 1, 000 to₯ 1, and small change notes were abolished for the last time. The third drachma assumed a fixed exchange rate of₯ 30 per dollar until 20 October 1973: over the next 25 years, the official exchange rate gradually declined, reaching 400 drachmae per dollar. On 1 January 2002, the Greek drachma was officially replaced as the circulating currency by the euro, and it has not been legal tender since 1 March 2002. Third modern drachma coins. The first issue of coins minted in 1954 consisted of holed aluminium 5-, 10- and 20- lepton pieces, with 50- lepton,₯ 1,₯ 2,₯ 5 and₯ 10 pieces in cupro- nickel. A silver₯ 20 piece was issued in 1960, replacing the₯ 20 banknote, and also minted only in collector sets in 1965. Coins in denominations from 50 lepta to₯ 20 carried a portrait of King Paul( 1947– 1964). New coins were introduced in 1966, ranging from 50 lepta to₯ 10, depicting King Constantine II( 1964– 1974). A silver₯ 30 coin for the centennial of Greece' s royal dynasty was minted in 1963. The following year a non- circulating coin of this value was produced to commemorate the royal wedding. The reverse of all coins was altered in 1971 to reflect the military junta which was in power from 1967 to 1974. This design included a soldier standing in front of the flames of the rising phoenix and the date of the coup d' état, April 21, 1967. A₯ 20 coin in cupro- nickel with an image of Europa on the obverse was issued in 1973. In late 1973, several new coin types were introduced: unholed aluminium(10λand20λ), nickel- brass( 50 lepta,₯ 1, and₯ 2) and cupro- nickel(₯ 5,₯ 10, and₯ 20). These provisional coins carried the design of the phoenix rising from the flame on the obverse, and used the country' s new designation as the" Hellenic Republic", replacing the coins also issued in 1973 as the Kingdom of Greece with King Constantine II' s portrait. A new series of all 8 denominations was introduced in 1976 carrying images of early national heroes on the smaller values. Cupro- nickel₯ 50 coins were introduced in 1980. In 1986, aluminium- bronze₯ 50 coins were introduced, followed by copper₯ 1 and₯ 2 pieces in 1988 and aluminium- bronze coins of₯ 20 and₯ 100 in 1990. In 2000, a set of 6 themed₯ 500 coins were issued to commemorate the 2004 Athens Olympic Games. Coins in circulation at the time of the adoption of the euro wereBanknotes. The first issues of banknotes were in denominations of₯ 10,₯ 20 and₯ 50, soon followed by₯ 100,₯ 500 and₯ 1, 000 | by 1956.₯ 5, 000 notes |
were introduced in 1984, followed by₯ 10, 000 notes in 1995 and₯ 200 notes in 1997. Banknotes in circulation at the time of the adoption of the euro wereEncoding. In Unicode, the currency symbol is. There is a special Attic numeral,, for the value of one drachma but it fails to render in most browsers. Restoration. The Drachmi Greek Democratic Movement Five Stars, which was founded in 2013, aims to restore the Drachma as Greece' s currency. External links. The denarius(, dēnāriī) was the standard Roman silver coin from its introduction in the Second Punic War to the reign of Gordian III( AD 238– 244), when it was gradually replaced by the Antoninianus. It continued to be minted in very small quantities, likely for ceremonial purposes, until and through the tetrarchy( 293– 313). The word" dēnārius" is derived from the Latin" dēnī"" containing ten", as its value was originally of 10 assēs. The word for" money" descends from it in Italian(" denaro"), Slovene(" denar"), Portuguese(" dinheiro"), and Spanish(" dinero"). Its name also survives in the dinar currency. Its symbol is represented in Unicode as𐆖( U+ 10196), however it can also be represented as X̶( capital letter X with combining long stroke overlay). History. A predecessor of the" denarius" was first struck in 269 or 268 BC, five years before the First Punic War, with an average weight of 6. 81 grams, or of a Roman pound. Contact with the Greeks had prompted a need for silver coinage in addition to the bronze currency that the Romans were using at that time. This predecessor of the" denarius" was a Greek- styled silver coin of" didrachm" weight, which was struck in Neapolis and other Greek cities in southern Italy. These coins were inscribed with a legend that indicated that they were struck for Rome, but in style they closely resembled their Greek counterparts. They were rarely seen at Rome, to judge from finds and hoards, and were probably used either to buy supplies or pay soldiers. The first distinctively Roman silver coin appeared around 226 BC. Classical historians have sometimes called these coins" heavy denarii", but they are classified by modern numismatists as" quadrigati", a term which survives in one or two ancient texts and is derived from the quadriga, or four- horse chariot, on the reverse. This, with a two- horse chariot or" biga" which was used as a reverse type for some early denarii, was the prototype for the most common designs used on Roman silver coins for a number of years. Rome overhauled its coinage shortly before 211 BC, and introduced the denarius alongside a short- lived denomination called the victoriatus. The denarius contained an average 4. 5 grams, or of a Roman pound, of silver, and was at first tariffed at ten asses, hence its name, which means' tenner'. It formed the backbone of Roman currency throughout the Roman republic and the early empire. The denarius began to undergo slow debasement toward the end of the republican period. Under the rule of Augustus( 27 BC to AD 14) its weight | fell to 3. 9 grams( |
a theoretical weight of of a Roman pound). It remained at nearly this weight until the time of Nero( AD 37– 68), when it was reduced to of a pound, or 3. 4 grams. Debasement of the coin' s silver content continued after Nero.LaterRomanemperorsalsoreduceditsweightto3gramsaroundthelate3rd century. The value at its introduction was 10 asses, giving the denarius its name, which translates as" containing ten". In about 141 BC, it was re- tariffed at 16 asses, to reflect the decrease in weight of the as. The denarius continued to be the main coin of the Roman Empire until it was replaced by the so-calledantoninianusintheearly3rd century AD. The coin was last issued, in bronze, under Aurelian between AD 270 and 275, and in the first years of the reign of Diocletian.(' Denarius', in" A Dictionary of Ancient Roman Coins", by John R. Melville- Jones( 1990)). Value, comparisons and silver content. 1 gold aureus= 2 gold quinarii= 25 silver denarii= 50 silver quinarii= 100 bronze sestertii= 200 bronze dupondii= 400 copper asses= 800 copper semisses= 1, 600 copper quadrantesItisdifficulttogiveevenroughcomparativevaluesformoneyfrombeforethe20th century, as the range of products and services available for purchase was so different. During the republic( 509 BC– 27 BC), a legionary earned 112. 5 denarii per year( 0. 3 denarii per day) Under Julius Caesar, this was doubled to 225 denarii/ yr, with soldiers having to pay for their own food and arms, while in the reign of Augustus a Centurion received at least 3, 750 denarii per year, and for the highest rank, 15, 000 denarii.. By the late Roman Republic and early Roman Empire(), a common soldier or unskilled laborer would be paid 1 denarius/ day( with no tax deductions), around 300% inflation compared to the early period. Using the cost of bread as a baseline, this pay equates to around US$ 20 in 2013 terms. Expressed in terms of the price of silver, and assuming 0. 999 purity, a troy ounce denarius had a precious metal value of around US$ 2. 60 in 2021. At the height of the Roman Empire a sextarius(546ml or about 2 1/ 4 cups) of ordinary wine cost roughly one Dupondius(⅛ of a Denarius), after Diocletian' s Edict on Maximum Prices were issued in AD 301, the same item cost 8 debased common denarii– 6, 400% inflation. Silver content plummeted across the lifespan of the denarius. Under the Roman Empire( after Nero) the denarius contained approximately 50 grains, 3. 24 grams, or( 0.105ozt) troy ounce. The fineness of the silver content varied with political and economic circumstances. From a purity of greater than 90%silverinthe1st century AD, the denarius fell to under 60% purity by AD 200, and plummeted to 5% purity by AD 300. By the reign of Gallienus, the" antoninianus" was a copper coin with a thin silver wash. Influence. In the final years ofthe1st century BC Tincomarus, a local ruler in southern Britain, started issuing coins that appear to have been made from melted down" denarii". The coins of Eppillus, issued around Calleva Atrebatum around the same time, appear to have derived design elements from | various" denarii" such as those |
of Augustus and M. Volteius. Even after the" denarius" was no longer regularly issued, it continued to be used as a unit of account, and the name was applied to later Roman coins in a way that is not understood. The Arabs who conquered large parts of the land that once belonged to the Eastern Roman Empire issued their own gold dinar. The lasting legacy of the" denarius" can be seen in the use of" d" as the abbreviation for the British penny until 1971. It also survived in France as the name of a coin, the denier. The denarius also survives in the common Arabic name for a currency unit, the" dinar" used from pre- Islamic times, and still used in several modern Arab nations. The major currency unit in former Principality of Serbia, Kingdom of Serbia and former Yugoslavia was" dinar", and it is still used in present- day Serbia. The Macedonian currency" denar" is also derived from the Roman denarius. The Italian word" denaro", the Spanish word" dinero", the Portuguese word" dinheiro", and the Slovene word"", all meaning money, are also derived from Latin" denarius". The pre- decimal currency of the United Kingdom until 1970 of pounds, shillings and pence was abbreviated as lsd, with" d" referring to denarius and standing for penny. Use in the Bible. In the New Testament, the gospels refer to the denarius as a day' s wage for a common laborer( Matthew 20: 2, John 12: 5). In the Book of Revelation, during the Third Seal: Black Horse, a choinix(" quart") of wheat and three quarts of barley were each valued at one denarius. Bible scholar Robert H. Mounce says the price of the wheat and barley as described in the vision appears to be ten to twelve times their normal cost in ancient times. Revelation thus describes a condition where basic goods are sold at greatly inflated prices. Thus, the black horse rider depicts times of deep scarcity or famine, but not of starvation. Apparently, a choinix of wheat was the daily ration of one adult. Thus, in the conditions pictured by Revelation 6, the normal income for a working- class family would buy enough food for only one person. The less costly barley would feed three people for one day' s wages. The denarius is also mentioned in the Parable of the Good Samaritan( Luke 10: 25– 37). The Render unto Caesar passage in Matthew 22: 15– 22 and Mark 12: 13– 17 uses the word( δηνάριον) to describe the coin held up by Jesus, translated in the King James Bible as" tribute penny". It is commonly thought to be a denarius with the head of Tiberius. The Della Rovere family(; literally" of the oak tree") was a noble family of Italy. It had humble origins in Savona, in Liguria, and acquired power and influence through nepotism and ambitious marriages arranged by two Della Rovere popes: Francesco Della Rovere, who ruled as Sixtus IV from 1471 to 1484) and his nephew Giuliano, who became Julius II in 1503. Sixtus IV built the | Sistine Chapel, which is named |
for him. The Basilica of San Pietro in Vincoli in Rome is the family church of the Della Rovere. Members of the family were influential in the Church of Rome, and as dukes of Urbino; that title was extinguished with the death of Francesco Maria II in 1631, and the family died out with the death of his granddaughter Vittoria, Grand Duchess of Tuscany. History. Francesco Della Rovere was born into a poor family in Liguria in north- west Italy in 1414, the son of Leonardo della Rovere of Savona. He was elected pope in 1471. As Sixtus IV he was both wealthy and powerful, and at once set about giving power and wealth to his nephews of the Della Rovere and Riario families. Within months of his election, he had made Giuliano della Rovere( the future pope Julius II) and Pietro Riario both cardinals and bishops; four other nephews were also made cardinals. He made Giovanni Della Rovere, who was not a priest, prefect of Rome, and arranged for him to marry into the da Montefeltro family, dukes of Urbino. Sixtus claimed descent from a noble Della Rovere family, the counts of Vinovo in Piemonte, and adopted their coat- of- arms. Guidobaldo da Montefeltro adopted Francesco Maria I della Rovere, his sister' s child and nephew of Pope Julius II. Guidobaldo I, who was heirless, called Francesco Maria at his court, and named him as heir of the Duchy of Urbino in 1504, this through the intercession of Julius II. In 1508, Francesco Maria inherited the duchy thereby starting the line of Rovere Dukes of Urbino. That dynasty ended in 1626 when Pope Urban VIII incorporated Urbino into the papal dominions. As compensation to the last sovereign duke, the title only could be continued by Francesco Maria II, and after his death by his heir, Federico Ubaldo. Vittoria, last descendant of the della Rovere family( she was the only child of Federico Ubaldo), married Ferdinando II de' Medici, Grand Duke of Tuscany. They had two children: Cosimo III, Tuscany' s longest reigning monarch, and Francesco Maria de' Medici, a prince of the Church. Other people with the same surname. Among the many people who did not belong to this family, but bore the same name, are: and various artists, including: David Alan Mamet(; born November 30, 1947) is an American playwright, filmmaker, and author. He won a Pulitzer Prize and received Tony nominations for his plays" Glengarry Glen Ross"( 1984) and" Speed- the- Plow"( 1988). He first gained critical acclaim for a trio of off-Broadway1970s plays:" The Duck Variations"," Sexual Perversity in Chicago", and" American Buffalo". His plays" Race" and" The Penitent", respectively, opened on Broadway in 2009 and previewed off- Broadway in 2017. Feature films that Mamet both wrote and directed include" House of Games"( 1987)," Homicide"( 1991)," The Spanish Prisoner"( 1997), and his biggest commercial success," Heist"( 2001). His screenwriting credits include" The Postman Always Rings Twice"( 1981)," The Verdict"( 1982)," The Untouchables"( 1987)," Hoffa"( 1992)," Wag the Dog"( 1997), and" Hannibal"( 2001). Mamet himself wrote the screenplay for | the 1992 adaptation of" Glengarry |
Glen Ross", and wrote and directed the 1994 adaptation of his play" Oleanna"( 1992). He was the executive producer and a frequent writer for the TV show" The Unit"( 2006– 2009). Mamet' s books include:" On Directing Film"( 1991), a commentary and dialogue about film- making;" The Old Religion"( 1997), a novel about the lynching of Leo Frank;" Five Cities of Refuge: Weekly Reflections on Genesis, Exodus, Leviticus, Numbers and Deuteronomy"( 2004), a Torah commentary with Rabbi Lawrence Kushner;" The Wicked Son"( 2006), a study of Jewish self- hatred and antisemitism;" Bambi vs. Godzilla", a commentary on the movie business;" The Secret Knowledge: On the Dismantling of American Culture"( 2011), a commentary on cultural and political issues; and" Three War Stories"( 2013), a trio of novellas about the physical and psychological effects of war. Early life. Mamet was born in 1947 in Chicago to Lenore June( née Silver), a teacher, and Bernard Morris Mamet, a labor attorney. His family was Jewish. His paternal grandparents were Polish Jews. One of Mamet' s earliest jobs was as a busboy at Chicago' s London House and The Second City. He also worked as an actor, editor for" Oui" magazine and as a cab- driver. He was educated at the progressive Francis W. Parker School and at Goddard College in Plainfield, Vermont.AttheChicagoPublicLibraryFoundation20th anniversary fundraiser in 2006, though, Mamet announced" My alma mater is the Chicago Public Library. I got what little educational foundation I got in the third- floor reading room, under the tutelage of a Coca- Cola sign". After a move to Chicago' s North Side, Mamet encountered theater director Robert Sickinger, and began to work occasionally at Sickinger' s Hull House Theatre. This represented the beginning of Mamet' s lifelong involvement with the theater. Career. Theater. Mamet is a founding member of the Atlantic Theater Company; he first gained acclaim for a trio of off- Broadway plays in 1976," The Duck Variations,"" Sexual Perversity in Chicago," and" American Buffalo." He was awarded the Pulitzer Prize in 1984 for" Glengarry Glen Ross," which received its first Broadway revival in the summer of 2005. His play" Race", which opened on Broadway on December 6, 2009 and featured James Spader, David Alan Grier, Kerry Washington, and Richard Thomas in the cast, received mixed reviews. His play" The Anarchist", starring Patti LuPone and Debra Winger, in her Broadway debut, opened on Broadway on November 13, 2012 in previews and was scheduled to close on December 16, 2012. His 2017 play" The Penitent" previewed off- Broadway on February 8, 2017. In 2002, Mamet was inducted into the American Theater Hall of Fame. Mamet later received the PEN/ Laura Pels Theater Award for Grand Master of American Theater in 2010. In 2017, Mamet released an online class for writers entitled" David Mamet teaches dramatic writing". In 2019 Mamet returned to the London West End with a new play," Bitter Wheat", at the Garrick Theatre, starring John Malkovich. Film. Mamet' s first film work was as a screenwriter, later directing his own scripts. Mamet' s first produced screenplay was the 1981 | production of" The Postman Always |
Rings Twice", based on James M. Cain' s novel. He received an Academy Award nomination one year later for the 1982 legal drama," The Verdict". He also wrote the screenplays for" The Untouchables"( 1987)," Hoffa"( 1992)," The Edge"( 1997)," Wag the Dog"( 1997)," Ronin"( 1998), and" Hannibal"( 2001). He received a second Academy Award nomination for" Wag the Dog". In 1987, Mamet made his film directing debut with his screenplay" House of Games", which won Best Film and Best Screenplay awards at the 1987 Venice Film Festival and the Film of the Year in 1989 from the London Film Critics' Circle Awards. The film starred his then- wife, Lindsay Crouse, and many longtime stage associates and friends, including fellow Goddard College graduates. Mamet was quoted as saying," It was my first film as a director and I needed support, so I stacked the deck." After" House of Games", Mamet later wrote and directed two more films focusing on the world of con artists," The Spanish Prisoner"( 1997) and" Heist"( 2001). Among those films," Heist" enjoyed the biggest commercial success. Other films that Mamet both wrote and directed include:" Things Change"( 1988)," Homicide"( 1991)( nominated for the Palme d' Or at 1991 Cannes Film Festival and won a" Screenwriter of the Year" award for Mamet from the London Film Critics' Circle Awards)," Oleanna"( 1994)," The Winslow Boy"( 1999)," State and Main"( 2000)," Spartan"( 2004)," Redbelt"( 2008), and the 2013 bio- pic TV movie" Phil Spector". A feature- length film, a thriller titled" Blackbird", was intended for release in 2015, but is still in development. When Mamet adapted his play for the 1992 film" Glengarry Glen Ross", he wrote an additional part( including the monologue" Coffee' s for closers") for Alec Baldwin. Mamet continues to work with an informal repertory company for his films, including Crouse, William H. Macy, Joe Mantegna, and Rebecca Pidgeon, as well as the aforementioned school friends. Mamet rewrote the script for" Ronin" under the pseudonym" Richard Weisz" and turned in an early version of a script for" Malcolm X" which was rejected by director Spike Lee. In 2000, Mamet directed a film version of" Catastrophe," a one- act play by Samuel Beckett featuring Harold Pinter and John Gielgud( in his final screen performance). In 2008, he wrote and directed the mixed martial arts movie" Redbelt," about a martial arts instructor tricked into fighting in a professional bout. In" On Directing Film", Mamet asserts that directors should focus on getting the point of a scene across, rather than simply following a protagonist, or adding visually beautiful or intriguing shots. Films should create order from disorder in search of the objective. Books. In 1986, Mamet published“ Writing in Restaurants” a collection of essays. In 1990, Mamet published" The Hero Pony", a 55- page collection of poetry. He has also published a series of short plays, monologues and four novels," The Village"( 1994)," The Old Religion"( 1997)," Wilson: A Consideration of the Sources"( 2000), and" Chicago"( 2018). He has written several non- fiction texts, and children' s stories, including" True and False: | Heresy and Common Sense for |
the Actor"( 1997). In 2004 he published a lauded version of the classical Faust story," Faustus", however, when the play was staged in San Francisco during the spring of 2004, it was not well received by critics. On May 1, 2010, Mamet released a graphic novel" The Trials of Roderick Spode( The Human Ant)". On June 2, 2011," The Secret Knowledge: On the Dismantling of American Culture", Mamet' s book detailing his conversion from modern liberalism to" a reformed liberal" was released. Mamet published" Three War Stories", a collection of novellas, on November 11, 2013. On December 3, 2019, Mamet was set to publish a novel," The Diary of a Porn Star by Priscilla Wriston- Ranger: As Told to David Mamet With an Afterword by Mr. Mamet." Television and radio. Mamet wrote one episode of" Hill Street Blues"," A Wasted Weekend", that aired in 1987. His then- wife, Lindsay Crouse, appeared in numerous episodes( including that one) as Officer McBride. Mamet is also the creator, producer and frequent writer of the television series" The Unit", where he wrote a well- circulated memo to the writing staff. He directed a third- season episode of" The Shield" with Shawn Ryan. In 2007, Mamet directed two television commercials for Ford Motor Company. The two 30- second ads featured the Ford Edge and were filmed in Mamet' s signature style of fast- paced dialogue and clear, simple imagery. Mamet' s sister, Lynn, is a producer and writer for television shows, such as" The Unit" and" Law& amp; Order". Mamet has contributed several dramas to BBC Radio through Jarvis& amp; Ayres Productions, including an adaptation of" Glengarry Glen Ross" for BBC Radio 3 and new dramas for BBC Radio 4. The comedy" Keep Your Pantheon( or On the Whole I' d Rather Be in Mesopotamia)" was aired in 2007." The Christopher Boy' s Communion" was another Jarvis& amp; Ayres production, first broadcast on BBC Radio 4 on March 8, 2021. Other media and political views. Since May 2005 he has been a contributing blogger at" The Huffington Post", drawing satirical cartoons with themes including political strife in Israel. In a 2008 essay at" The Village Voice" titled" Why I Am No Longer a' Brain- Dead Liberal'" he revealed that he had gradually rejected so- called political correctness and progressivism and embraced conservatism. Mamet has spoken in interviews of changes in his views, highlighting his agreement with free market theorists such as Friedrich Hayek the historian Paul Johnson, and economist Thomas Sowell, whom Mamet called" one of our greatest minds". During promotion of a book, Mamet said British people had" a taint of anti- semitism," claiming they" want to give[ Israel] away to some people whose claim is rather dubious." In the same interview, Mamet went on to say that" there are famous dramatists and novelists[ in the UK] whose works are full of anti- Semitic filth." He refused to give examples because of British libel laws( the interview was conducted in New York City for the" Financial Times"). He is known for his pro- Israel positions; in | his book" The Secret Knowledge" |
he claimed that" Israelis would like to live in peace within their borders; the Arabs would like to kill them all." Mamet wrote an article for the November 2012 issue of" The Jewish Journal of Greater Los Angeles" imploring fellow Jewish Americans to vote for Republican nominee Mitt Romney. In an essay for" Newsweek", published on January 29, 2013, Mamet argued against gun control laws:" It was intended to guard us against this inevitable decay of government that the Constitution was written. Its purpose was and is not to enthrone a Government superior to an imperfect and confused electorate, but to protect us from such a government." Mamet has described the NFL anthem protests as" absolutely fucking despicable". In a 2020 interview, he described Donald Trump as a" great president" and supported his re- election. Mamet is a contributing editor to Flying magazine. Critical reception to Mamet." Mamet speak". Mamet' s style of writing dialogue, marked by a cynical, street- smart edge, precisely crafted for effect, is so distinctive that it has come to be called" Mamet speak." Mamet himself has criticized his( and other writers') tendency to write" pretty" at the expense of sound, logical plots. When asked how he developed his style for writing dialogue, Mamet said," In my family, in the days prior to television, we liked to while away the evenings by making ourselves miserable, based solely on our ability to speak the language viciously. That' s probably where my ability was honed." One instance of Mamet' s dialogue style can be found in" Glengarry Glen Ross", in which two down- on- their- luck real estate salesmen are considering stealing from their employer' s office. George Aaronow and Dave Moss equivocate on the meaning of" talk" and" speak", turning language and meaning to deceptive purposes: Mamet dedicated" Glengarry Glen Ross" to Harold Pinter, who was instrumental in its being first staged at the Royal National Theatre,( London) in 1983, and whom Mamet has acknowledged as an influence on its success, and on his other work. Mamet and gender issues. Mamet' s plays have frequently sparked debate and controversy. Following a 1992 staging of" Oleanna", a play in which a college student accuses her professor of trying to rape her, a critic reported that the play divided the audience by gender and recounted that" couples emerged screaming at each other". In his 2014 book" David Mamet and Male Friendship", Arthur Holmberg examined Mamet' s portrayal of male friendships, especially focusing on the contradictions and ambiguities of male bonding as dramatized in Mamet' s plays and films. Personal life. Mamet and actress Lindsay Crouse married in 1977 and divorced in 1990. The couple have two children, Willa and Zosia. Willa was a professional photographer and is now a singer/ songwriter; Zosia is an actress. Mamet has been married to actress and singer- songwriter Rebecca Pidgeon since 1991. They live together in Santa Monica, California. They have two children, Clara and Noah. Mamet is a Reform Jew and strongly pro- Israel. Archive. The papers of David Mamet were sold to the | Harry Ransom Center at the |
University of Texas at Austin in 2007 and first opened for research in 2009. The growing collection consists mainly of manuscripts and related production materials for most of his plays, films, and other writings, but also includes his personal journals from 1966 to 2005. In 2015, the Ransom Center secured a second major addition to Mamet' s papers, including more recent works. Additional materials relating to Mamet and his career can be found in the Ransom Center' s collections of Robert De Niro, Mel Gussow, Tom Stoppard, Sam Shepard, Paul Schrader, Don DeLillo, and John Russell Brown. Works. Mamet is credited as writer of these works except where noted. Credits in addition to writer also noted. Informally, a definable real number is a real number that can be uniquely specified by its description. The description may be expressed as a construction or as a formula of a formal language. For example, the positive square root of 2,formula_1,canbedefinedastheuniquepositivesolutiontotheequationformula_2, and it can be constructed with a compass and straightedge. Different choices of a formal language or its interpretation give rise to different notions of definability. Specific varieties of definable numbers include the constructible numbers of geometry, the algebraic numbers, and the computable numbers. Because formal languages can have only countably many formulas, every notion of definable numbers has at most countably many definable real numbers. However, by Cantor' s diagonal argument, there are uncountably many real numbers, so almost every real number is undefinable. Constructible numbers. One way of specifying a real number uses geometric techniques.Arealnumberformula_3isaconstructiblenumberifthereisamethodtoconstructalinesegmentoflengthformula_3 using a compass and straightedge, beginning with a fixed line segment of length 1. Each positive integer, and each positive rational number, is constructible. The positive square root of 2 is constructible. However, the cube root of 2 is not constructible; this is related to the impossibility of doubling the cube. Real algebraic numbers.Arealnumberformula_3iscalledarealalgebraicnumberifthereisapolynomialformula_6, with only integer coefficients,sothatformula_3isarootofformula_8, that is,formula_9. Each real algebraic number can be defined individually using the order relation on the reals. For example,ifapolynomialformula_10 has 5 real roots,thethirdonecanbedefinedastheuniqueformula_3suchthatformula_12andsuchthattherearetwodistinctnumberslessthanformula_3atwhichformula_14 is zero. All rational numbers are algebraic, and all constructible numbers are algebraic. There are numbers such as the cube root of 2 which are algebraic but not constructible. The real algebraic numbers form a subfield of the real numbers. This means that 0 and 1 are algebraic numbers and, moreover,ifformula_15andformula_16 are algebraic numbers,thensoareformula_17,formula_18,formula_19 and,ifformula_16 is nonzero,formula_21. The real algebraic numbers also have the property, which goes beyond being a subfield of the reals,thatforeachpositiveintegerformula_22andeachrealalgebraicnumberformula_15,alloftheformula_22throotsofformula_15 that are real numbers are also algebraic. There are only countably many algebraic numbers, but there are uncountably many real numbers, so in the sense of cardinality most real numbers are not algebraic. This nonconstructive proof that not all real numbers are algebraic was first published byGeorg Cantor in his 1874 paper" On a Property of the Collection of All Real Algebraic Numbers". Non- algebraic numbers are called transcendental numbers. The best known transcendental numbers are and. Computable real numbers. A real number is a computable number if there is an algorithm that, given a natural numberformula_22, produces a decimal expansion for the | number accurate toformula_22 decimal places. |
This notion was introduced by Alan Turing in 1936.Thecomputablenumbersincludethealgebraicnumbersalongwithmanytranscendentalnumbersincludingformula_28 Like the algebraic numbers, the computable numbers also form a subfield of the real numbers,andthepositivecomputablenumbersareclosedundertakingformula_22th roots for eachNot all real numbers are computable. Specific examples of noncomputable real numbers include the limits of Specker sequences, and algorithmically random real numbers such as Chaitin' s Ω numbers. Definability in arithmetic. Another notion of definability comes from the formal theories of arithmetic, such as Peano arithmetic. The language of arithmetic has symbols for 0, 1, the successor operation, addition, and multiplication, intended to be interpreted in the usual way over the natural numbers. Because no variables of this language range over the real numbers, a different sort of definability is needed to refer to real numbers.Arealnumberformula_15 is" definable in the language of arithmetic"( or" arithmetical") if its Dedekind cut can be defined as a predicate in that language; that is, if there is a first-orderformulaformula_31 in the language of arithmetic, with three free variables,suchthatformula_32 of the arithmetical hierarchy, one of the lowest levels. Similarly, the reals with arithmetical Dedekind cuts form the lowest level of the analytical hierarchy. Definability in models of ZFC.Arealnumberformula_15 is first- order definable in the language of set theory, without parameters,ifthereisaformulaformula_31 in the language of set theory, with one free variable,suchthatformula_15istheuniquerealnumbersuchthatformula_36 holds. This notion cannot be expressed as a formula in the language of set theory. All analytical numbers, and in particular all computable numbers, are definable in the language of set theory. Thus the real numbers definable in the language of set theory include all familiar real numbers such as 0, 1,formula_28,formula_38, et cetera, along with all algebraic numbers. Assuming that they form a set in the model, the real numbers definable in the language of set theory over a particular model of ZFC form a field.Eachsetmodelformula_39 of ZFC set theory that contains uncountablymanyrealnumbersmustcontainrealnumbersthatarenotdefinablewithinformula_39( without parameters). This follows from the fact that there are only countably many formulas,andsoonlycountablymanyelementsofformula_39canbedefinableoverformula_39. Thus,ifformula_39 has uncountably many real numbers, one can prove from" outside"formula_39thatnoteveryrealnumberofformula_39isdefinableoverformula_39. This argument becomes more problematic if it is applied to class models of ZFC, such as the von Neumann universe. The assertion"therealnumberformula_47 is definable over the" class"modelformula_48" cannot be expressed as a formula of ZFC. Similarly, the question of whether the von Neumann universe contains real numbers that it cannot define cannot be expressed as a sentence in the language of ZFC. Moreover, there are countable models of ZFC in which all real numbers, all sets of real numbers, functions on the reals, etc. are definable. Diego de Almagro(;– July 8, 1538), also known as El Adelantado and El Viejo, was a Spanish conquistador known for his exploits in western South America. He participated with Francisco Pizarro in the Spanish conquest of Peru. While subduing the Inca Empire he laid the foundation for Quito and Trujillo as Spanish cities in present- day Ecuador and Peru respectively. From Peru Almagro led the first Spanish military expedition to central Chile. Back in Peru, a longstanding conflict with Pizarro over the control of the former Inca capital of Cuzco erupted into a civil war | between the two bands of |
conquistadores. In the battle of Las Salinas in 1538 Almagro was defeated by the Pizarro brothers and months later he was executed. Early years. The origins of Diego de Almagro were humble. He was born in 1475 in the village of Almagro, in Ciudad Real, where he was given the name of the village for his surname as he was the illegitimate son of Juan de Montenegro and Elvira Gutiérrez. In order to preserve the honor of his mother, her relatives took the infant Diego and took him to the nearby town of Bolaños de Calatrava, where he was raised by Sancha López del Peral, later moving to Aldea del Rey. At the age of four he returned to Almagro, and was placed under the tutelage of an uncle named Hernán Gutiérrez. At age fifteen he ran away from home because of his uncle' s harshness. He went to the home of his mother, who was now living with her new husband, to tell her what had happened and that he was going to travel the world, and asked for some bread. His mother, anguished, gave him a piece of bread and some coins and said:" Take, son, and do not give me more trouble, and go, and God help you in your adventure." He went to Seville and after probably stealing to survive, Almagro became a" criado" or servant of Don Luis Gonzalez de Polanco, one of the four" Alcaldes de la Casa y Corte de Su Majestad" and later a Counselor of the Catholic Monarchs. While living in Seville, Almagro stabbed another servant in an argument, inflicting serious enough injuries that he was to be tried in court. Don Luis, using his influence, prevailed upon Don Pedro Arias Dávila to allow Almagro to embark in one of the ships going to the New World from the port of Sanlucar de Barrameda. The Casa de Contratacion( royal agency for the Spanish Empire required that the men who crossed the Atlantic provide their own weapons, clothes, and farming tools, which Don Polanco provided to his servant. Arrival in America. Diego de Almagro, now in his late thirties, arrived in the New World on June 30, 1514, with the expedition that Ferdinand II of Aragon had sent under the leadership of Dávila. The expedition arrived at the city of Santa María la Antigua del Darién, Panama, where many other future conquistadors were already assembled, among them Francisco Pizarro. There are not many details of Almagro' s activities during this period, but it is known that he accompanied various sailors who departed from Darien between 1514 and 1515. He eventually returned and settled in Darien, where he was granted an encomienda, building a house and making a living from agriculture. Almagro undertook his first independent conquest on November 1515, commanding 260 men as he founded Villa del Acla, named after the Indian place. Due to illness he had to hand over command to Gaspar de Espinosa. Espinosa decided to undertake a new expedition, which departed in December 1515 with 200 men, including Almagro and | Francisco Pizarro, who for the |
first time was designated as a captain. During this expedition, which lasted 14 months, Almagro, Pizarro and Hernando de Luque became close friends. Also during this time Almagro established a friendship with Vasco Núñez de Balboa, who was in charge of Acla. Almagro wanted to have a ship built with the remaining materials of the Espinosa expedition, to be finished on the coast of the" Great South Sea", as the Pacific Ocean was first called by the Spanish. Current historians do not believe that Almagro was expected to participate in Balboa' s expedition and probably returned to Darien. Almagro took part in the various expeditions that took place in the Gulf of Panama, including those of Espinosa, which were supported by Balboa' s ships. Almagro was recorded as a witness on the lists of natives whom Espinosa ordered to be carried. He remained as an early settler in the newly founded city of Panama, staying there for four years, managing his properties and those of Pizarro. He took Ana Martínez, an indigenous woman, as a common- law wife. In this period, his first son," El Mozo", was born to them. Conquest of Peru. By 1524 an association of conquest regarding South America was formalized among Almagro, Pizarro and Luque. By the beginning of August 1524, they had received the requisite permission to discover and conquer lands further south. De Almagro would remain in Panama to recruit men and gather supplies for the expeditions led by Pizarro. After several expeditions to South America, Pizarro secured his stay in Peru with the" Capitulation" on 6 July 1529. During Pizarro' s continued exploration of Incan territory, he and his men succeeded in defeating the Inca army under Emperor Atahualpa during the Battle of Cajamarca in 1532. De Almagro joined Pizarro soon afterward, bringing more men and arms. After Peru fell to the Spanish, both Pizarro and De Almagro initially worked together in the founding of new cities to consolidate their dominions. As such, Pizarro dispatched De Almagro to pursue Quizquiz, fleeing to the Inca Empire' s northern city of Quito. Their fellow conquistador Sebastián de Belalcázar, who had gone forth without Pizarro' s approval, had already reached Quito and witnessed the destruction of the city by Inca general Rumiñawi. The Inca warrior had ordered the city to be burned and its gold to be buried at an undisclosed location where the Spanish could never find it. The arrival of Pedro de Alvarado from Guatemala, in search of Inca gold further complicated the situation for Almagro and Belalcázar. Alvarado' s presence, however, did not last long as he left South America in exchange for monetary compensation from Pizarro. In an attempt to claim Quito ahead of Belalcázar, in August 1534 De Almagro founded a city on the shores of Laguna de Colta( Colta Lake) in the foothills of Chimborazo, some south of present- day Quito, and named it" Santiago de Quito." Four months later would come the foundation of the Peruvian city of Trujillo, which Almagro named as" Villa Trujillo de Nueva Castilla"( the Village of | Trujillo in New Castille) in |
honor of Francisco Pizarro' s birthplace, Trujillo in Extremadura, Spain. These events were the height of the Pizarro- Almagro friendship, which historians describe as one of the last events in which their friendship soon faded and entered a period of turmoil for the control of the Incan capital of Cuzco. Conflict with Pizarro. After splitting the treasure of Inca emperor Atahualpa, both Pizarro and Almagro left towards Cuzco and took the city in 1533. However, De Almagro' s friendship with Pizarro showed signs of deterioration in 1526 when Pizarro, in the name of the rest of the conquistadors, called forth the" Capitulacion de Toledo" law in which King Charles I of Spain had laid out his authorization for the conquest of Peru and the awards every conquistador would receive from it. Long before, however, each conquistador had promised to equally split the benefits. Pizarro managed to have a larger stake and awards for himself. Despite this, De Almagro still obtained an important fortune for his services, and the King awarded him in November 1532 the noble title of" Don" and he was assigned a personal coat of arms. Although by this time Diego de Almagro had already acquired sufficient wealth in the conquest of Peru and was living a luxurious life in Cuzco, the prospect of conquering the lands further south was very attractive to him. Given that the dispute with Pizarro over Cuzco had kept intensifying, Almagro spent a great deal of time and money equipping a company of 500 men for a new exploration south of Peru. By 1534 the Spanish crown had determined to split the region in two parallel lines, forming the governorship of" Nueva Castilla"( from the 1° to the 14° latitude, close to Pisco), and that of" Nueva Toledo"( from the 14° to the 25° latitude, in Taltal, Chile), assigning the first to Francisco Pizarro and the second to Diego de Almagro. The crown had previously assigned Almagro the governorship of Cuzco, and as such De Almagro was heading there when Charles V divided the territory between Nueva Castilla and Nuevo Toledo. This might have been the reason why Almagro did not immediately confront Pizarro for Cuzco, and promptly decided to embark on his new quest for the discovery of the riches of Chile. Discovery of Chile. The preparations. Charles V had given Diego a grant extending two hundred leagues south of Francisco Pizarro' s. Francisco and Diego concluded a new contract on 12 June 1535, in which they agreed to share future discoveries equally. Diego raised an expedition for Chile, expecting it" would lead to even greater riches than they had found in Peru." Almagro prepared the way by sending ahead three of his Spanish soldiers, the religious chief of the Inca empire, Willaq Umu, and Paullo Topa, brother of Manco Inca Yupanqui. De Almagro sent Juan de Saavedra forward with one hundred and fifty men, and soon followed them with additional forces. Saavedra established on January 23, 1535 the first Spanish settlement in Bolivia near the Inca regional capital of Paria. Following the Inca | Trail and crossing the Andes. |
Almagro left Cuzco on July 3,1535withhissupportersandstoppedatMoinauntilthe20th of that month. Meanwhile, Francisco Pizarro' s brother, Juan Pizarro, had arrested Inca Manco Inca Yupanqui, further complicating De Almagro' s plans as it heavily increased the dissatisfaction of the Indians submitted to Spanish rule. Not having formally been appointed governor of any territories in the Capitulation of Toledo in 1528, however, forcing him to declare himself" adelantado"( governor) of Nueva Toledo, or southern Peru and present- day Chile. Some sources suggest Almagro received such a requirement in 1534 by the Spanish king and was officially declared governor of New Toledo. Once he left Moina, De Almagro followed the Inca trail followed by 750 Spaniards deciding to join him in quest for the gold lost in the ransom of Atahualpa, which had mainly benefited the Pizarro brothers and their supporters. After crossing the Bolivian mountain range and traveling past Lake Titicaca, Almagro arrived on the shores of the Desaguadero River and finally set up camp in Tupiza. From there, the expedition stopped at Chicoana and then turned to the southeast to cross the Andes mountains. The expedition turned out to be a difficult and exhausting endeavor. The hardest phase was the crossing of the Andean cordilleras: the cold, hunger and tiredness meant the death of various Spanish and natives, but mainly slaves who were not accustomed to such rigorous climate. Upon this point, De Almagro determined everything was a failure. He ordered a small group under Rodrigo Orgóñez on a reconnaissance of the country to the south. By luck, these men found the Valley of Copiapó, where Gonzalo Calvo Barrientos, a Spanish soldier whom Pizarro had expelled from Peru for stealing objects the Inca had offered for his ransom, had already established a friendship with the local natives. There, in the valley of the river Copiapó, Almagro took official possession of Chile and claimed it in the name of King Charles V. Dismayed in Chile. De Almagro promptly initiated the exploration of the new territory, starting up the valley the Aconcagua River, where he was well received by the natives. However, the intrigues of his interpreter, Felipillo, who had previously helped Pizarro in dealing with" Atahualpa", almost thwarted De Almagro' s efforts. Felipillo had secretly urged the local natives to attack the Spanish, but they desisted, not understanding the dangers that they posed. De Almagro directed Gómez de Alvarado along with 100 horsemen and 100 foot to continue the exploration, which ended in the confluence of the Ñuble and Itata rivers. The Battle of Reinohuelén between the Spanish and Mapuche indigenous peoples forced the explorers to return to the north. De Almagro' s own reconnaissance of the land and the bad news of Gómez de Alvarado' s encounter with the fierce Mapuche, along with the bitter cold winter that settled ferociously upon them, only served to confirm that everything had failed. He never found gold or the cities which Incan scouts had told him lay ahead, only communities of the indigenous population who lived from subsistence agriculture. Local tribes put up fierce resistance to the Spanish | forces. The exploration of the |
territories of Nueva Toledo, which lasted 2 years, was marked by a complete failure for De Almagro. Despite this, at first he thought staying and founding a city would serve well for his honor. The initial optimism that led Almagro to bring his son he had with the indigenous Panamanian Ana Martínez to Chile had faded. Some historians have suggested that, but for the urging of his senior explorers, De Almagro would probably have stayed permanently in Chile. He was urged to return to Peru and this time take definitive possession of Cuzco, so as to consolidate an inheritance for his son. Dismayed with his experience in the south, Almagro made plans of return to Peru. He never officially founded a city in the territory of what is now Chile. The withdrawal of the Spanish from valleys of Chile was violent: Almagro authorized his soldiers to ransack the natives' properties, leaving their soil desolate. In addition, the Spanish soldiers took natives captive to serve as slaves. The locals were captured, tied together, and forced to carry the heavy loads belonging to the conquistadors. Return to Peru. After the exhausting crossing of the Atacama Desert, mainly due to the harsh weather conditions, Almagro finally reached Cuzco, Peru, in 1537. According to some authors, it was during this time that the Spanish term" roto"( torn), used by Peruvians to refer to Chileans, was first coined. De Almagro' s disappointed troops returned to Cuzco with their" torn clothes" due to the extensive and laborious passage on foot by the Atacama Desert. After his return, De Almagro was surprised to learn of the Inca Manco' s rebellion. Diego de Almagro sent an embassy to the Inca, but they mistrusted all of the Spaniards by this time. Hernando Pizarro' s men formed an uneasy truce with De Almagro' s men, surveying to determine the boundaries of their leaders' royal grants. They needed to determine in which portion the city of Cuzco was located. However, De Almagro' s troops quickly took the city and imprisoned the Pizarro brothers, Hernando and Gonzalo, on the night of 8 April 1537. After occupying Cuzco, De Almagro confronted an army sent by Francisco Pizarro to liberate his brothers. Alonso de Alvarado commanded it and was defeated during the Battle of Abancay on July 12, 1537. He and some of his men were imprisoned. Later, Gonzalo Pizarro and De Alvarado escaped prison. Subsequent negotiations between Francisco Pizarro and De Almagro concluded with the liberation of Hernando, the third Pizarro brother, in return for conceding control and administration of Cuzco to De Almagro. Pizarro never intended to give up the city permanently, but was buying time to organize an army strong enough to defeat Almagro' s troops. During this time De Almagro fell ill, and Pizarro and his brothers grabbed the opportunity to defeat him and his followers. The Almagristas were defeated at Las Salinas in April 1538, with Orgóñez being killed on the field of battle. De Almagro fled to Cuzco, still in the hands of his loyal supporters, but found only temporary | refuge; the forces of the |
Pizarro brothers entered the city without resistance. Once captured, Almagro was humiliated by Hernando Pizarro and his requests to appeal to the King were ignored. When Diego de Almagro begged for his life, Hernando responded:"- he was surprised to see Almagro demean himself in a manner so unbecoming a brave cavalier, that his fate was no worse than had befallen many a soldier before him; and that, since God had given him the grace to be a Christian, he should employ his remaining moments in making up his account with Heaven!" Almagro was condemned to death and executed by" garrote" in his dungeon, and then decapitated, on July 8, 1538. His corpse was taken to the public Plaza Mayor of Cuzco, where a herald proclaimed his crimes. Hernán Ponce de León took his body and buried him in the church of Our Lady of Mercy in Cuzco. El Mozo. Diego de Almagro II( 1520– 1542), known as" El Mozo"( The Lad), son of Diego de Almagro I, whose mother was an Indian girl of Panama, became the foil of the conspirators who had put Pizarro to the sword. Pizarro was murdered on June 26, 1541; the conspirators promptly proclaimed the lad De Almagro Governor of Peru. From various causes, all of the conspirators either died or were killed except for one, who was executed after the lad Almagro gave an order. The lad De Almagro fought the desperate battle of Chupas on September 16, 1542, escaped to Cuzco, but was arrested, immediately condemned to death, and executed in the great square of the city. Divinity or the divine are things that are either related to, devoted to, or proceeding from a deity. What is or is not divine may be loosely defined, as it is used by different belief systems. The root of the word" divine" is literally" godly," but the use varies significantly depending on which deity is being discussed. For specific related academic terms, see Divinity( academic discipline), or Divine( Anglican). Usages. Divinity as a quality has two distinct usages: Overlap occurs between these usages because deities or godly entities are often identical with or identified by the powers and forces that are credited to them— in many cases a deity is merely a power or force personified— and these powers and forces may then be extended or granted to mortal individuals. For instance, Jehovah is closely associated with storms and thunder throughout much of the Old Testament. He is said to speak in thunder, and thunder is seen as a token of his anger. This power was then extended to prophets like Moses and Samuel, who caused thunderous storms to rain down on their enemies. Divinity always carries connotations of goodness, beauty, beneficence, justice, and other positive, pro- social attributes. In monotheistic faiths there is an equivalent cohort of malefic supernatural beings and powers, such as demons, devils, afreet, etc., which are not conventionally referred to as divine;" demonic" is often used instead. Pantheistic and polytheistic faiths make no such distinction; gods and other beings of transcendent power often | have complex, ignoble, or even |
irrational motivations for their acts. Note that while the terms" demon" and" demonic" are used in monotheistic faiths as antonyms to" divine", they are in fact derived from the Greek word" daimón"( δαίμων), which itself translates as" divinity". There are three distinct usages of" divinity" and" divine" in religious discourse: Entity. In monotheistic faiths, the word" divinity" is often used to refer to the singular God central to that faith. Often the word takes the definite article and is capitalized—" the Divinity"— as though it were a proper name or definitive honorific." Divine"— capitalized— may be used as an adjective to refer to the manifestations of such a Divinity or its powers: e. g." basking in the Divine presence..." The terms" divinity" and" divine"— uncapitalized, and lacking the definite article— are sometimes used as to denote' god( s) or certain other beings and entities which fall short of absolute Godhood but lie outside the human realm. These include( by no means an exhaustive list): Divine force or power. As previously noted, divinities are closely related to the transcendent force( s) or power( s) credited to them, so much so that in some cases the powers or forces may themselves be invoked independently. This leads to the second usage of the word" divine"( and a less common usage of" divinity"): to refer to the operation of transcendent power in the world. In its most direct form, the operation of transcendent power implies some form of divine intervention. For pan- and polytheistic faiths this usually implies the direct action of one god or another on the course of human events. In Greek legend, for instance, it was Poseidon( god of the sea) who raised the storms that blew Odysseus' s craft off course on his return journey, and Japanese tradition holds that a god- sent wind saved them from Mongol invasion. Prayers or propitiations are often offered to specific gods of pantheisms to garner favorable interventions in particular enterprises: e. g. safe journeys, success in war, or a season of bountiful crops. Many faiths around the world— from Japanese Shinto and Chinese traditional religion, to certain African practices and the faiths derived from those in the Caribbean, to Native American beliefs— hold that ancestral or household deities offer daily protection and blessings. In monotheistic religions, divine intervention may take very direct forms: miracles, visions, or intercessions by blessed figures. Transcendent force or power may also operate through more subtle and indirect paths. Monotheistic faiths generally support some version of divine providence, which acknowledges that the divinity of the faith has a profound but unknowable plan always unfolding in the world. Unforeseeable, overwhelming, or seemingly unjust events are often thrown on' the will of the Divine', in deferences like the Muslim" inshallah"(' as God wills it') and Christian' God works in mysterious ways'. Often such faiths hold out the possibility of divine retribution as well, where the divinity will unexpectedly bring evil- doers to justice through the conventional workings of the world; from the subtle redressing of minor personal wrongs, to such large- scale havoc | as the destruction of Sodom |
and Gomorrah or the biblical Great Flood. Other faiths are even more subtle: the doctrine of" karma" shared by Buddhism and Hinduism is a divine law similar to divine retribution but without the connotation of punishment: our acts, good or bad, intentional or unintentional, reflect back on us as part of the natural working of the universe. Philosophical Taoism also proposes a transcendent operant principle— transliterated in English as" tao" or" dao", meaning' the way'— which is neither an entity or a being per se, but reflects the natural ongoing process of the world. Modern western mysticism and new age philosophy often use the term' the Divine' as a noun in this latter sense: a non- specific principle or being that gives rise to the world, and acts as the source or wellspring of life. In these latter cases the faiths do not promote deference, as happens in monotheisms; rather each suggests a path of action that will bring the practitioner into conformance with the divine law:" ahimsa"—' no harm'— for Buddhist and Hindu faiths;" de" or" te"—' virtuous action'— in Taoism; and any of numerous practices of peace and love in new age thinking. Mortals. In the third usage, extensions of divinity and divine power are credited to living, mortal individuals. Political leaders are known to have claimed actual divinity in certain early societies— the ancient Egyptian Pharaohs being the premier case— taking a role as objects of worship and being credited with superhuman status and powers. More commonly, and more pertinent to recent history, leaders merely claim some form of divine mandate, suggesting that their rule is in accordance with the will of God. The doctrine of the divinerightofkingswasintroducedaslateasthe17th century, proposing that kings rule by divine decree; Japanese Emperors ruled by divine mandate until the inception of the Japanese constitution after World War II. Less politically, most faiths have any number of people that are believed to have been touched by divine forces: saints, prophets, heroes, oracles, martyrs, and enlightened beings, among others. Saint Francis of Assisi, in Catholicism, is said to have received instruction directly from God and it is believed that he grants plenary indulgence to all who confess their sins and visit his chapel on the appropriate day. In Greek mythology, Achilles' mother bathed him in the river Styx to give him immortality, and Hercules— as the son of Zeus— inherited near- godly powers. In religious Taoism, Lao Tsu is venerated as a saint with his own powers. Various individuals in the Buddhist faith, beginning with Siddhartha, are considered to be enlightened, and in religious forms of Buddhism they are credited with divine powers. Christ in the Bible is said to be God' s Son and is said to have performed divine miracles. In general, mortals with divine qualities are carefully distinguished from the deity or deities in their religion' s main pantheon. Even the Christian faith, which generally holds Christ to be identical to God, distinguishes between God the Father and Christ the begotten Son. There are, however, certain esoteric and mystical schools of thought, present | in many faiths— Sufis in |
Islam, Gnostics in Christianity, Advaitan Hindus, Zen Buddhists, as well as several non- specific perspectives developed in new age philosophy— which hold that all humans are in essence divine, or unified with the Divine in a non- trivial way. Such divinity, in these faiths, would express itself naturally if it were not obscured by the social and physical worlds we live in; it needs to be brought to the fore through appropriate spiritual practices. Christianity. In the New Testament the Greek word θεῖον(" theion") in the Douay Version, is translated as" divinity". Examples are below: The word translated as either" deity"," Godhead", or" divinity" in the Greek New Testament is also the Greek word θεότητος(" theotētos"), and the one verse that contains it is this: Colossians 2:9The word" divine" in the New Testament is the Greek word θείας(" theias"), and is the adjective form of" divinity". Biblical examples from the King James Bible are below: Latter- day Saints. The most prominent conception of divine entities in The Church of Jesus Christ of Latter- day Saints( LDS Church) is the Godhead, a divine council of three distinct beings: Elohim( the Father), Jehovah( the Son, or Jesus), and the Holy Spirit. Joseph Smith described a nontrinitarian Godhead, with God the Father and Jesus Christ each having individual physical bodies, and the Holy Spirit as a distinct personage with a spirit body. Smith also introduced the existence of a Heavenly Mother in the King Follett Discourse, but very little is acknowledged or known beyond her existence. Mormons hold a belief in the divine potential of humanity; Smith taught a form of divinization where mortal men and women can become like god through salvation and exaltation. Lorenzo Snow succinctly summarized this using a couplet, which is often repeated within the LDS Church:" As man now is, God once was: As God now is, man may be." Epicureanism. Epicurean philosophy admits the existence of gods, but since it does not accept the supernatural and teaches that all things are material, posits a theology where the Epicurean gods are physical beings whose bodies are made of atoms and who live in the region between the words( intermundia). Needless to say, these gods do not need our worship, are not creators or maintainers of the cosmos, nor do they answer prayers. Therefore, Epicurean theology belongs properly in the realm of speculation about super- evolved, intelligent extraterrestrial life. However, Epicurus of Samos( the founder of the School) recognized the utility of religiosity and its central, unifying symbols. He was adamant in his requirement that his disciples be pious, and established two taboos concerning their conception of the gods: they had to believe that their gods were immortal( that is, indestructible and fully self- sufficient) and blessed( happy, or blissful). Outside of that, Epicureans are free to speculate concerning the nature of the highest life- forms in the cosmos. For many cameras, depth of field( DOF) is the distance between the nearest and the farthest objects that are in acceptably sharp focus in an image. The depth of field can be | calculated based on focal length, |
distance to subject, the acceptable circle of confusion size, and aperture. A particular depth of field may be chosen for technical or artistic purposes. Limitations of depth of field can sometimes be overcome with various techniques/ equipment. Factors affecting depth of field. For cameras that can only focus on one object distance at a time, depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus." Acceptably sharp focus" is defined using a property called the" circle of confusion". The depth of field can be determined by focal length, distance to subject, the acceptable circle of confusion size, and aperture. The approximate depth of field can be given by: for a given circle of confusion( c), focal length( f), f- number( N), and distance to subject( u). As distance or the size of the acceptable circle of confusion increases, the depth of field increases; however, increasing the size of the aperture or increasing the focal length reduces the depth of field. Depth of field changes linearly with F- number and circle of confusion, but changes in proportional to the square of the focal length and the distance to the subject. As a result, photos taken at extremely close range have a proportionally much smaller depth of field. Sensor size affects DOF in counterintuitive ways. Because the circle of confusion is directly tied to the sensor size, decreasing the size of the sensor while holding focal length and aperture constant will" decrease" the depth of field( by the crop factor). The resulting image however will have a different field of view. If the focal length is altered to maintain the field of view, the change in focal length will counter the decrease of DOF from the smaller sensor and" increase" the depth of field( also by the crop factor). Effect of lens aperture. For a given subject framing and camera position, the DOF is controlled by the lens aperture diameter, which is usually specified as the f- number( the ratio of lens focal length to aperture diameter). Reducing the aperture diameter( increasing the f- number) increases the DOF because only the light travelling at shallower angles passes through the aperture. Because the angles are shallow, the light rays are within the acceptable circle of confusion for a greater distance. For a given size of the subject' s image in the focal plane, the same f- number on any focal length lens will give the same depth of field. This is evident from the DOF equation by noting that the ratio" u/ f" is constant for constant image size. For example, if the focal length is doubled, the subject distance is also doubled to keep the subject image size the same. This observation contrasts with the common notion that" focal length is twice as important to defocus as f/ stop", which applies to a constant subject distance, as opposed to constant image size. Motion pictures make only limited use of aperture control; to produce a consistent image quality from shot to shot, cinematographers usually choose a | single aperture setting for interiors |
and another for exteriors, and adjust exposure through the use of camera filters or light levels. Aperture settings are adjusted more frequently in still photography, where variations in depth of field are used to produce a variety of special effects. Effect of circle of confusion. Precise focus is only possible at an exact distance from the lens; at that distance, a point object will produce a point image. Otherwise, a point object will produce a blur spot shaped like the aperture, typically and approximately a circle. When this circular spot is sufficiently small, it is visually indistinguishable from a point, and appears to be in focus. The diameter of the largest circle that is indistinguishable from a point is known as the acceptable circle of confusion, or informally, simply as the circle of confusion. Points that produce a blur spot smaller than this acceptable circle of confusion are considered acceptably sharp. The acceptable circle of confusion depends on how the final image will be used. It is generally accepted to be 0. 25 mm for an image viewed from 25 cm away. For 35 mm motion pictures, the image area on the film is roughly 22 mm by 16 mm. The limit of tolerable error was traditionally set at 0. 05 mm( 0. 002 in) diameter, while for 16 mm film, where the size is about half as large, the tolerance is stricter, 0. 025 mm( 0. 001 in). More modern practice for 35 mm productions set the circle of confusion limit at 0. 025 mm( 0. 001 in). Camera movements. The term" camera movements" refers to swivel( swing and tilt, in modern terminology) and shift adjustments of the lens holder and the film holder.Thesefeatureshavebeeninusesincethe1800s and are still in use today on view cameras, technical cameras, cameras with tilt/ shift or perspective control lenses, etc. Swiveling the lens or sensor causes the plane of focus( POF) to swivel, and also causes the field of acceptable focus to swivel with the POF; and depending on the DOF criteria, to also change the shape of the field of acceptable focus. While calculations for DOF of cameras with swivel set to zero have been discussed, formulated,anddocumentedsincebeforethe1940s, documenting calculations for cameras with non- zero swivel seem to have begun in 1990. More so than in the case of the zero swivel camera, there are various methods to form criteria and set up calculations for DOF when swivel is non- zero. There is a gradual reduction of clarity in objects as they move away from the POF, and at some virtual flat or curved surface the reduced clarity becomes unacceptable. Some photographers do calculations or use tables, some use markings on their equipment, some judge by previewing the image. When the POF is rotated, the near and far limits of DOF may be thought of as wedge- shaped, with the apex of the wedge nearest the camera; or they may be thought of as parallel to the POF. Object- field calculation methods. Traditional depth- of- field formulas can be hard to use in practice. As an alternative, | the same effective calculation can |
be done without regard to the focal length and f- number. Moritz von Rohr and later Merklinger observe that the effective absolute aperture diameter can be used for similar formula in certain circumstances. Moreover, traditional depth- of- field formulas assume equal acceptable circles of confusion for near and far objects. Merklinger suggested that distant objects often need to be much sharper to be clearly recognizable, whereas closer objects, being larger on the film, do not need to be so sharp. The loss of detail in distant objects may be particularly noticeable with extreme enlargements. Achieving this additional sharpness in distant objects usually requires focusing beyond the hyperfocal distance, sometimes almost at infinity. For example, if photographing a cityscape with a traffic bollard in the foreground, this approach, termed the" object field method" by Merklinger, would recommend focusing very close to infinity, and stopping down to make the bollard sharp enough. With this approach, foreground objects cannot always be made perfectly sharp, but the loss of sharpness in near objects may be acceptable if recognizability of distant objects is paramount. Other authors such as Ansel Adams have taken the opposite position, maintaining that slight unsharpness in foreground objects is usually more disturbing than slight unsharpness in distant parts of a scene. Overcoming DOF limitations. Some methods and equipment allow altering the apparent DOF, and some even allow the DOF to be determined after the image is made. For example, focus stacking combines multiple images focused on different planes, resulting in an image with a greater( or less, if so desired) apparent depth of field than any of the individual source images. Similarly, in order to reconstruct the 3- dimensional shape of an object, a depth map can be generated from multiple photographs with different depths of field. Xiong and Shafer concluded, in part,"... the improvements on precisions of focus ranging and defocus ranging can lead to efficient shape recovery methods." Another approach is focus sweep. The focal plane is swept across the entire relevant range during a single exposure. This creates a blurred image, but with a convolution kernel that is nearly independent of object depth, so that the blur is almost entirely removed after computational deconvolution. This has the added benefit of dramatically reducing motion blur. Other technologies use a combination of lens design and post- processing: Wavefront coding is a method by which controlled aberrations are added to the optical system so that the focus and depth of field can be improved later in the process. The lens design can be changed even more: in colour apodization the lens is modified such that each colour channel has a different lens aperture. For example, the red channel may be" f"/ 2. 4, green may be" f"/ 2. 4, whilst the blue channel may be" f"/ 5. 6. Therefore, the blue channel will have a greater depth of field than the other colours. The image processing identifies blurred regions in the red and green channels and in these regions copies the sharper edge data from the blue channel. The result is an image | that combines the best features |
from the different" f"- numbers. At the extreme,aplenopticcameracaptures4D light field information about a scene, so the focus and depth of field can be altered after the photo is taken. Diffraction and DOF. Diffraction causes images to lose sharpness at high F- numbers, and hence limits the potential depth of field. In general photography this is rarely an issue; because large f- numbers typically require long exposure times, motion blur may cause greater loss of sharpness than the loss from diffraction. However, diffraction is a greater issue in close- up photography, and the tradeoff between DOF and overall sharpness can become quite noticeable as photographers are trying to maximise depth of field with very small apertures. Hansma and Peterson have discussed determining the combined effects of defocus and diffraction using a root- square combination of the individual blur spots. Hansma' s approach determines the f- number that will give the maximum possible sharpness; Peterson' s approach determines the minimum f- number that will give the desired sharpness in the final image, and yields a maximum depth of field for which the desired sharpness can be achieved. In combination, the two methods can be regarded as giving a maximum and minimum f- number for a given situation, with the photographer free to choose any value within the range, as conditions( e. g., potential motion blur) permit. Gibson gives a similar discussion, additionally considering blurring effects of camera lens aberrations, enlarging lens diffraction and aberrations, the negative emulsion, and the printing paper. Couzin gave a formula essentially the same as Hansma' s for optimal" f"- number, but did not discuss its derivation. Hopkins, Stokseth, and Williams and Becklund have discussed the combined effects using the modulation transfer function. DOF scales. Many lenses include scales that indicate the DOF for a given focus distance and f- number; the 35 mm lens in the image is typical. That lens includes distance scales in feet and meters; when a marked distance is set opposite the large white index mark, the focus is set to that distance. The DOF scale below the distance scales includes markings on either side of the index that correspond to f- numbers. When the lens is set to a given f- number, the DOF extends between the distances that align with the f- number markings. Photographers can use the lens scales to work backwards from the desired depth of field to find the necessary focus distance and aperture. For the 35 mm lens shown, if it were desired for the DOF to extend from 1 m to 2 m, focus would be set so that index mark was centered between the marks for those distances, and the aperture would be set to f/ 11. On a view camera, the focus and f- number can be obtained by measuring the depth of field and performing simple calculations. Some view cameras include DOF calculators that indicate focus and f- number without the need for any calculations by the photographer. Near: far distribution. The DOF beyond the subject is always greater than the DOF in front of | the subject. When the subject |
is at the hyperfocal distance or beyond, the far DOF is infinite, so the ratio is 1:∞; as the subject distance decreases, near: far DOF ratio increases, approaching unity at high magnification. For large apertures at typical portrait distances, the ratio is still close to 1: 1. DOF formulae. This section covers some additional formula for evaluating depth of field; however they are all subject to significant simplifying assumptions: for example, they assume the paraxial approximation of Gaussian optics. They are suitable for practical photography, lens designers would use significantly more complex ones. Focus and f- number from DOF limits.ForgivennearandfarDOFlimitsformula_2andformula_3, the required f- number is smallest when focus is set tothe harmonic mean of the near and far distances. In practice, this is equivalent to the arithmetic mean for shallow depths of field. Sometimes,viewcamerausersrefertothedifferenceformula_5 as the" focus spread". Foreground and background blur.Ifasubjectisatdistanceformula_6andtheforegroundorbackgroundisatdistanceformula_7, letthedistancebetweenthesubjectandtheforegroundorbackgroundbeindicatedbyTheblurdiskdiameterformula_9ofadetailatdistanceformula_10fromthesubjectcanbeexpressedasafunctionofthesubjectmagnificationformula_11,focallengthformula_12, f-numberformula_13,oralternativelytheapertureformula_14, according toThe minus sign applies to a foreground object, and the plus sign applies to a background object. The blur increases with the distance from the subject;whenformula_9 is less than the circle of confusion, the detail is within the depth of field. The Dumnonii or Dumnones were a British tribe who inhabited Dumnonia, the area now known as Devon and Cornwall( and some areas of present- day Dorset and Somerset) in the further parts of the South West peninsula of Britain, from at least the Iron Age up to the early Saxon period. They were bordered to the east by the Durotriges tribe. Etymology. William Camden, in his 1607 edition of" Britannia", describes Cornwall and Devon as being two parts of the same' country' which: Camden had learnt some Welsh during the course of his studies and it would appear that he is the origin of the interpretation of Dumnonii as" deep valley dwellers" from his understanding of the Welsh of his time. John Rhys later theorized that the tribal name was derived from the name of a goddess," Domnu", probably meaning" the goddess of the deep". The proto- Celtic root* dubno- or* dumno- meaning" the deep" or" the earth"( or alternatively meaning" dark" or" gloomy") appears in personal names such as Dumnorix and Dubnovellaunus. Another group with a similar name but with no known links were the Fir Domnann of Connacht. The Roman name of the town of Exeter," Isca Dumnoniorum"(" Isca of the Dumnonii"), contains the root"* iska-"" water" for" Water of the Dumnonii". The Latin name suggests that the city was already an" oppidum", or walled town, on the banks on the River Exe before the foundation of the Roman city, in about AD 50. The Dumnonii gave their name to the English county of Devon, and their name is represented in Britain' s two extant Brythonic languages as" Dewnans" in Cornish and" Dyfnaint" in Welsh. Amédée Thierry(" Histoire des Gaulois", 1828), one of the inventors of the" historic race" of Gauls, could confidently equate them with the Cornish(" les Cornouailles"). Victorian historians often referred to the tribe as the Damnonii, which is also the name of another people from lowland Scotland, although there are | no known links between the |
two populations. Language. The people of Dumnonia spoke a Southwestern Brythonic dialect similar to the forerunner of more recent Cornish and Breton. Irish immigrants, the Déisi, are evidenced by the Ogham- inscribed stones they have left behind, confirmed and supplemented by toponymical studies. The stones are sometimes inscribed in Latin, sometimes in both scripts. Tristram Risdon suggested the continuance of a Brythonic dialect in the South Hams, Devon,aslateasthe14th century, in addition to its use in Cornwall. Territory. Ptolemy's2nd century" Geography" places the Dumnonii to the west of the Durotriges. The name" purocoronavium" that appears in the Ravenna Cosmography implies the existence of a sub- tribe called the Cornavii or Cornovii, perhaps the ancestors of the Cornish people. Gaius Iulius Solinus,probablyinthe3rd century, remarks:" This turbid strait also divides the island Silura from the shore which is held by the Dumnonii, a British tribe. The men of this island even now preserve an old custom: they do not use coins. They give and accept, obtaining the necessities of life by exchange rather than by money. They reverence gods, and the men and women equally declare knowledge of the future." In the sub- Roman period a Brythonic kingdom called Dumnonia emerged, covering the entire peninsula, although it is believed by some to have effectively been a collection of sub- kingdoms. A kingdom of Domnonée( and of Cornouaille alongside) was established in the province of Armorica directly across the English Channel, and has apparent links with the British population, suggesting an ancient connection of peoples along the western Atlantic seaboard. Settlements. Isca Dumnoniorum. The Latin name for Exeter is Isca Dumnoniorum(" Water of the Dumnonii"). This oppidum( a Latin term meaning an important town) on the banks of I River Exe certainly existed prior to the foundation of the Roman city in about AD 50." Isca" is derived from the Brythonic word for flowing water, which was given to the River Exe. This is reflected in the Welsh name for Exeter:" Caerwysg" meaning" fortified settlement on the river Uisc". Isca Dumnoniorum originated with a settlement that developed around the Roman fortress of the Legio II Augusta and is one of the four" poleis"( cities) attributed to the tribe by Ptolemy. It isalsolistedintworoutesofthelate2nd century Antonine Itinerary. A legionary bath- house was built inside the fortress sometime between 55 and 60 and underwent renovation shortly afterwards( c. 60- 65) but by c. 68( perhaps even 66) the legion had transferred to a newer fortress at Gloucester. This saw the dismantling of the Isca fortress, and the site was then abandoned. Around AD 75, work on the" civitas forum" and" basilica" had commenced on the site of the former" principia"andbythelate2nd century the" civitas" walls had been completed. They were 3 metres thick and 6 metres high and enclosed exactly the same area as the earlier fortress. However,bythelate4th century the" civitas" was in decline. Other settlements. As well as Isca Dumnoniorum, Ptolemy's2nd century" Geography" names three other towns: The Ravenna Cosmography includes the last two names( in slightly different forms, as" Tamaris" and" Uxelis"), and adds several more names which | may be settlements in the |
territory. These include: Other Romano- British sites in Dumnonia include: New settlements continued to be built throughout the Roman period, including sites at Chysauster and Trevelgue Head. The style is native in form with no Romanised features. Near Padstow, a site of some importance that was inhabited from the late Bronze/earlyIronAgetothemid6th century now lies buried under the sands on the opposite side of the Camel estuary near St. Enodoc' s Church, and may have been a western coastal equivalent of a Saxon Shore Fort. Byzantine and African pottery has been discovered at the site. At Magor Farm in Illogan, near Camborne, an archaeological site has been identified as being a villa. Archaeology. The Dumnonii are thought to have occupied relatively isolated territory in Cornwall, Devon, Somerset and possibly part of Dorset. Their cultural connections, as expressed in their ceramics, were with the peninsula of Armorica across the Channel, rather than with the southeast of Britain. They do not seem to have been politically centralised: coins are relatively rare, none of them locally minted, and the structure, distribution and construction of Bronze Age and Iron Age hill forts," rounds" and defensible farmsteads in the south west point to a number of smaller tribal groups living alongside each other. Dumnonia is noteworthy for its many settlements that have survived from the Romano- British period, but also for its lack of a villa system. Local archaeology has revealed instead the isolated enclosed farmsteads known locally as" rounds". These seem to have survived the Roman abandonment of Britain, but were subsequently replaced,inthe6thand7th centuries, by the unenclosed farms taking the Brythonic toponymic" tre-". As in most other Brythonic areas, Iron Age hill forts, such as Hembury Castle, were refortified for the use of chieftains or kings. Other high- status settlements such as Tintagel seem to have been reconstructed during this period. Post- Roman imported pottery has been excavated from many sites across the region,andtheapparentsurgeinlate5th century Mediterranean and/ or Byzantine imports is yet to be explained satisfactorily. Industries. Apart from fishing and agriculture, the main economic resource of the Dumnonii was tin mining. The area of Dumnonia had been mined since ancient times, and the tin was exported from the ancient trading port of Ictis( St Michael' s Mount). Tin extraction( mainly by streaming) had existed here from theearlyBronzeAgearoundthe22nd century BC. West Cornwall, around Mount' s Bay, was traditionally thought to have been visited by metal traders from the eastern MediterraneanDuring the first millennium BC trade became more organised, first with the Phoenicians, who settled Gades( Cadiz) around 1100 BC, and later with the Greeks, who had settled Massilia( Marseilles) and Narbo( Narbonne) around 600 BC. Smelted Cornish tin was collected at Ictis whence it was conveyed across the Bay of Biscay to the mouth of the Loire and then to Gades via the Loire and Rhone valleys. It went then through the Mediterranean Sea in ships to Gades. During the period c. 500- 450 BC, the tin deposits seem to have become more important, and fortified settlements appear such as at Chun Castle and Kenidjack Castle, to | protect both the tin smelters |
and mines.TheearliestaccountofCornishtinminingwaswrittenbyPytheasofMassilialateinthe4th century BC after his circumnavigation of the British Isles. Underground mining was described in this account, although it cannot be determined when it had started. Pytheas' s account was noted later by other writers including Pliny the Elder and Diodorus Siculus. It is likely that tin trade with the Mediterranean was later on under the control of the Veneti. Britain was one of the places proposed for the" Cassiterides", that is Tin Islands. Tin working continued throughout Roman occupation although it appears that output declined because of new supplies brought in from the deposits discovered in Iberia( Spain and Portugal). However, when these supplies diminished,productioninDumnoniaincreasedandappearstohavereachedapeakduringthe3rd century AD. Sub- Roman and post- Roman Dumnonia. The Sub- Roman or Post- Roman history of Dumnonia comes from a variety of sources and is considered exceedingly difficult to interpret given that historical fact, legend and confused pseudo- history are compounded by a variety of sources in Middle Welsh and Latin. The main sources available for discussion of this period include Gildas' s" De Excidio Britanniae" and Nennius' s" Historia Brittonum", the" Annales Cambriae"," Anglo- Saxon Chronicle", William of Malmesbury' s" Gesta Regum Anglorum" and" De Antiquitate Glastoniensis Ecclesiae", along with texts from the" Black Book of Carmarthen" and the" Red Book of Hergest", and Bede' s" Historia ecclesiastica gentis Anglorum" as well as" The Descent of the Men of the North"(" Bonedd Gwŷr y Gogledd", in Peniarth MS 45 and elsewhere) and the" Book of Baglan". A declaration of independence or declaration of statehood or proclamation of independence is an assertion by a polity in a defined territory that it is independent and constitutes a state. Such places are usually declared from part or all of the of another state or failed state, or are breakaway territories from within the larger state. In 2010, the UN' s International Court of Justice ruled in an advisory opinion in Kosovo that" International law contains no prohibition on declarations of independence", though the state from which the territory wishes to secede may regard the declaration as rebellion, which may lead to a war of independence or a constitutional settlement to resolve the crisis. Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. The race follows a short, straight course from a standing start over a measured distance, most commonly, with a shorter() distance becoming increasingly popular, as it has become the standard for Top Fuel dragsters and funny cars, where some major bracket races and other sanctioning bodies have adopted it as the standard. The is also popular in some circles. Electronic timing and speed sensing systems have been used to recordraceresultssincethe1960s. The history of automobiles and motorcycles being used for drag racing is nearly as long as the history of motorized vehicles themselves, and has taken the form of both illegal street racing and as a regulated motorsport. History. Drag racing started inthe1940s. World War II veterans were prominently involved, and some early drag races were done | at decommissioned aircraft bases with |
landing strips that made them an ideal place for the sport. In 1951, Wally Parks formed the National Hot Rod Association( NHRA). The organization banned the use of nitromethane in 1957, calling it unsafe, in part through the efforts of C. J. Hart; the ban would be lifted in 1963. Basics of drag racing. Starting. Push starts to get engines running were necessary until the National Hot Rod Association( NHRA) mandated self- starters in 1976. After burnouts, cars would be pushed back by crews; this persisted until NHRA required reversing systems in 1980. Don Garlits was the first to do burnouts across the starting line, which is now standard practice. Each driver then backs up to and stages at the starting line. Prerace preparations. Before each race( commonly known as a pass), each driver is allowed to perform a burnout, which heats the driving tires and lays rubber down at the beginning of the track, improving traction. The cars run through a" water box"( formerly a" bleach box", before bleach was replaced by flammable traction compound, which produced spectacular, and dangerous, flame burnouts;thehazardledNHRAtomandateuseofwaterinthe1970s). Modern races are started electronically by a system known as a" Christmas tree", which consists of a column of lights for each driver/ lane, and two light beam sensors per lane on the track at the starting line. Current NHRA trees, for example, feature one blue light( split into halves), then three amber, one green, and one red. When the first light beam is broken by a vehicle' s front tire( s), the vehicle is" pre- staged"( approximately from the starting line), and the pre- stage indicator on the tree is lit. When the second light beam is broken, the vehicle is" staged", and the stage indicator on the tree is lit. Vehicles may then leave the pre- stage beam, but must remain in the stage beam until the race starts. Staging. Once one competitor is staged, their opponent has a set amount of time to stage or they will be instantly disqualified, indicated by a red light on the tree. Otherwise, once both drivers are staged, the system chooses a short delay at random( to prevent a driver being able to anticipate the start), then starts the race. The light sequence at this point varies slightly. For example, in NHRA Professional classes, three amber lights on the tree flash simultaneously, followed 0. 4 seconds later by a green light( this is also known as a" pro tree"). In NHRA Sportsman classes, the amber lights illuminate in sequence from top to bottom, 0. 5 seconds apart, followed 0. 5 seconds later by the green light( this is also known as a" sportsman tree" or" full tree"). If a vehicle leaves the starting line before the green light illuminates, the red light for that lane illuminates instead, and the driver is disqualified( also known as" red lighting"). In a handicap start, the green light automatically lights up for the first driver, and the red light is only lit in the proper lane after both cars have launched if one driver | leaves early, or if both |
drivers left early, the driver whose reaction time is worse( if one lane has a-. 015 and the other lane has a-. 022, the lane of the driver who committed a 0. 022 is given the red light after both cars have left), as a red light infraction is only assessed to the driver with the worse infraction, if both drivers leave early. Even if both drivers leave early, the green light is automatically lit for the driver that left last, and they still may win the pass( as in the 2014 NHRA Auto Club Pro Stock final, Erica Enders- Stevens and Jason Line both committed red light infractions; only Line was assessed with a red light, as he was-. 011 versus Enders- Stevens'-. 002). Measurements. Several measurements are taken for each race: reaction time, elapsed time, and speed. Reaction time is the period from the green light illuminating to the vehicle leaving the staging beams or breaking the guard beam. Elapsed time is the period from the vehicle leaving the starting line to crossing the finish line. Speed is measured through a speed trap covering the final to the finish line, indicating average speed of the vehicle in that distance. Except where a breakout rule is in place, the winner is the first vehicle to cross the finish line, and therefore the driver with the lowest combined reaction time and elapsed time. Because these times are measured separately, a driver with a slower elapsed time can actually win if that driver' s advantage in reaction time exceeds the elapsed time difference. In heads- up racing, this is known as a" holeshot win". In categories where a breakout rule is in effect( for example, NHRA Junior Dragster, Super Comp, Super Gas, Super Stock, and Stock classes, as well as some dial- in classes), if a competitor is faster than his or her predetermined time( a" breakout"), that competitor loses. If both competitors are faster than their predetermined times, the competitor who breaks out by less time wins. Regardless, a red light foul is worse than a breakout, except in Junior Dragster where exceeding the absolute limit is a cause for disqualification. Bracket system. Most race events use a traditional bracket system, where the losing car and driver are eliminated from the event while the winner advances to the next round, until a champion is crowned. Events can range from 16 to over 100 car brackets. Drivers are typically seeded by elapsed times in qualifying. In bracket racing without a breakout( such as NHRA Competition Eliminator), pairings are based on times compared to their index( faster than index for class is better). In bracket racing with a breakout( Stock, Super Stock, but also the NHRA' s Super classes), the closest to the index is favorable. A popular alternative to the standard eliminations format is the Chicago Style format( also called the Three Round format in Australia), named for the US 30 Dragstrip in suburban Gary, Indiana where a midweek meet featured this format. All entered cars participate in one qualifying round, and then | are paired for the elimination |
round. The two fastest times among winners from this round participate in the championship round. Depending on the organization, the next two fastest times may play for third, then fifth, and so forth, in consolation rounds. Currently, an IHRA 400 Thunder championship race in Australia uses the format. Distances. The standard distance of a drag race is 1, 320 feet, 402 m, or 1/ 4 mile(+- 0, 2% FIA& amp; NHRA rules). However, due to safety concerns, certain sanctioning bodies( notably the NHRA for its Top Fuel and Funny Car classes) have shortened races to 1, 000 feet. Some drag strips are even shorter and run 660 feet, 201 m, or 1/ 8 mile. The 1, 000 foot distance is now also popular with bracket racing, especially in meets where there are 1/ 8 mile cars and 1/ 4 mile cars racing together, and is used by the revived American Drag Racing League for its primary classes( not Jr Dragster). Some organizations that deal with Pro Modified and" Mountain Motor" Pro Stock cars( Professional Drag Racers Association) use the 1/ 8 mile distance, even if the tracks are 1/ 4 mile tracks. Racing organizations. North America. The National Hot Rod Association( NHRA) oversees the majority of drag racing events in North America. The next largest organization is the International Hot Rod Association( IHRA). Nearly all drag strips are associated with one sanctioning body or the other. Besides NHRA and IHRA, there are niche organizations for muscle cars and nostalgia vehicles. The Nostalgia Drag Racing League( NDRL) based in Brownsburg, IN, runs a series of 1/ 4 mile( 402 m) drag races in the Midwest for 1979 and older nostalgic appearing cars, with four classes of competition running in an index system. Pro 7. 0 and Pro 7. 50 run heads up 200 mile per hour( 320 kilometre per hour) passes, while Pro Comp and Pro Gas run 8. 0 to 10. 0 indices. NDRL competition vehicles typically include Front Engine Dragsters, Altereds, Funny Cars, early Pro Stock clones, Super Stocks and Gassers. The National Electric Drag Racing Association( NEDRA) races electric vehicles against high performance gasoline- powered vehicles such as Dodge Vipers or classic muscle cars in 1/ 4 and 1/ 8 mile( 402 m& amp; 201 m) races. The current electric drag racing record is 6. 940 seconds at 201. 37 mph( 324. 0736 km/ h) for a quarter mile( 402 m). Another niche organization is the VWDRC which run a VW- only championship with vehicles running under 7 seconds. Prior to the founding of the NHRA and IHRA, smaller organizations sanctioned drag racing in the early years, which included the competing AHRA in the United States from 1955 to 2005. Australia. The first Australian Nationals event was run in 1965 at Riverside raceway, near Melbourne. The Australian National Drag Racing Association( ANDRA) was established in 1973, and today they claim they are the" best in the world outside the United States". ANDRA sanctions races throughout Australia and throughout the year at all levels, from Junior Dragster to Top Fuel. The | ANDRA Drag Racing Series is |
for professional drivers and riders and includes Top Fuel, Top Alcohol, Top Doorslammer( similar to the USA Pro Modified class), Pro Stock( using 400 cubic inch engines( 6. 5 litres)), Top Bike and Pro Stock Motorcycle. The Summit Sportsman Series is for ANDRA sportsman drivers and riders and includes Competition, Super Stock, Super Compact, Competition Bike, Supercharged Outlaws, Top Sportsman, Modified, Super Sedan, Modified Bike, Super Street and Junior Dragster. In 2015, after a dispute with ANDRA, Sydney Dragway, Willowbank Raceway and the Perth Motorplex invited the International Hot Rod Association( IHRA) to sanction events at their tracks. Shortly thereafter the Perth Motorplex reverted to ANDRA sanction. Although greatly assisted by ANDRA priorto its construction, Springmount Raceway opted for IHRA sanction. The 400 Thunder Series targets professional racers to its races. Intended to be the premier Drag racing series in Australia it has never been ableto run a truly National series and has been on a steady decline since its inception. Most recently Top Fuel Australia( the organization that represents the Top Fuel owners) recently extracted itself from the 400 Thunder series. ANDRA recently launched a new National series that will initially cater for Top Doorslammer and Top Fue Motorcycle. This series will provide a greater National coverage than the 400 Thunder Series did and will soon add other Professional categories. In 2021 Heathcote Park Raceway in Victoria was sold to new ownership and has since been sanctioned by IHRA for small regional events. Europe. Drag racing was imported to Europe by American NATO troops during the Cold War.RaceswereheldinWestGermanybeginninginthe1960s at the airbases at Ramstein and Sembach and in the UK at various airstrips and racing circuits before the opening of Europe' s first permanent drag strip at Santa Pod Raceway in 1966. The FIA organises a Europe- wide four wheeled championship for the Top Fuel, Top Methanol Dragster, Top Methanol Funny Car, Pro Modified and Pro Stock classes. FIM Europe organises a similar championship for bike classes. In addition, championships are run for sportsman classes in many countries throughout Europe by the various national motorsport governing bodies. New Zealand. DragracinginNewZealandstartedinthe1960s. The New Zealand Hot Rod Association( NZHRA) sanctioned what is believed to have been the first drag meeting at an open cut coal mine at Kopuku, south of Auckland, sometime in 1966. In 1973, the first and only purpose built drag strip opened in Meremere by the Pukekohe Hot Rod Club. In April 1993 the governance of drag racing was separated from the NZHRA and the New Zealand Drag Racing Association( NZDRA) was formed. In 2014, New Zealand' s second purpose built drag strip– Masterton Motorplex– opened. The first New Zealand Drag Racing Nationals was held in the 1966/ 67 season at Kopuku, near Auckland. There are now two governing bodies operating drag racing in New Zealand with the Florida- based International Hot Rod Association sanctioning both of New Zealands major tracks at Ruapuna( Pegasus Bay Drag Racing Association) in the South Island and Meremere Dragway Inc in the North Island which is now become the best drag strip in NZ. However, | the official ASN of the |
sport, per FIA regulations, is the New Zealand Drag Racing Association. South America. Many countries in South America race 200 meters, unlike in the United States and Australia, where the quarter- mile, or, 400 meters, respectively, is typical.OrganizeddragracinginColombiaistheresponsibilityofClubG3, a private organization. The events take place at Autódromo de Tocancipá. Caribbean. CuraçaoOn the island of Curaçao, organization of drag racing events is handled by the Curaçao Autosport Foundation( FAC) All racing events, including street legal competitions, happen at the Curaçao International Raceway. Aruba. On the island of Aruba, all racing events, including street legal competitions, happen at Palomarga International Raceway. BarbadosOn the island of Barbados, organization of drag racing events is done by the Barbados Association of Dragsters and Drifters. Currently the drag racing is done at Bushy Park racing circuit over 1/ 8 mile, while" acceleration tests" of 1/ 4 mile are done at the Paragon military base. Saint LuciaOn the Island of Saint Lucia, organization of drag racing events is done by no- one. All local groups are tie ups. Currently races are held at the US Old military base also known as the" Ca Ca Beff"," The Base" near the Hewanorra International Airport in Vieux Fort. Dominican RepublicOn Santo Domingo, organization of drag racing events is done by Autodromo Sunix and they happen at the Autodromo Sunix, close to the Airport SDQ. South Asia. Organized drag racing is rapidly growing in India. The country' s first drag race meet was organized by" Autocar India" in Mumbai in 2002. Since then there have been many drag racing events in India. The most popular event is Elite Octanes' Valley Run which is held at Ambey Valley air strip in Loanavla every year. The biggest drag series event was organized by India Speed Week with three different locations around India. After the series two riders were chosen to represent the country 2017 initiative to bring 11 times world drag racing champion Rickey Gadson to India. The initiative was executed during the Valley Run 2017 event, which gave the participants a platform to perform at the highest level globally. Rickey Gadson, as an extension of the initiative invited two of the top performing drag racers to visit USA to train and get an opportunity to represent India at the World Finals of drag racing held on 16- 18 November 2018 in Valdosta GA, USA. As a result the two riders performed in their maiden event outside India. Also during the event, Amit Sharma, the fastest drag racer in Indian drag racing history, produced a time slip of 8. 87 sec' s– the fastest ever by any Indian. Drag racing is also gaining popularity in Pakistan, with private organizations sponsoring such events. The Bahria Town housing project recently organized a drag racing event in Rawalpindi with the help of some of the country' s best drivers. Sri Lanka has seen an immense growth in drag racing due to legal meets held by the Ceylon Motor Sports Club, an FIA sanctioned body. In recent years, exotic cars and Japanese power houses have been taking part in | these popular events. South Africa. |
Drag racing is an established sport in South Africa, with a number of strips around the country including Tarlton International Raceway and ODI Raceway. Drag racing is controlled by Motorsport South Africa and all drivers are required to hold a valid Motorsport South Africa license. Drivers can compete in a number of categories including Top Eliminator, Senior Eliminator, Super Competition Eliminator, Competition Eliminator, Pro Street Bikes, Superbike Eliminator, Supersport Shootout( motorcycle), Street Modified, and Factory Stock. Russian Federation. Drag racing in Russia started in 2004 in Moscow when the Russian Automotive Federation( RAF) sanctioned it as an official motorsport. Drag Racing became popular in Russia after" The Fast and the Furious" film in 2001, but competitions were illegal before 2004. The most outstanding drag racing event of the early years was" DRAG BITVA"( Drag Battle) which took place in Krasnoyarsk, Siberia from 2005 to 2008. Krasnoyarsk is located in the middle of Russia, so it was the best place to bring all the fastest cars from all over the country. Due to the financial situation" DRAG BITVA" was canceled in 2009 and never came back. It was difficult times for drag racing in Russia from 2009 to 2014, but it was supported by enthusiasts in every region. There were a lot of competitions but it wasn' t as big as" DRAG BITVA". In 2014 Dragtimes company in partnership with SMP Racing became the Russian Drag Racing Championship( SMP RDRC) promoters, since then Drag Racing in Russia became more professional. From the very beginning to 2014 only streetcars were allowed to compete in Russia. Now it' s also allowed to run promods and dragsters in SMP RDRC. Thanks to the efforts of SMP RDRC promoters in 2019 the first professional dragstrip in Russia" RDRC Racepark" was built. It' s located near Moscow in 40 kilometers of downtown at the former airfield Bykovo. It gave many opportunities to test the cars and make new records. Before the track was built, competitions took place on straight parts of circuits, so it wasn' t allowed to prepare the whole 1/ 4 mile, only 1/ 8 and the tracks were available for drag racers except racing weekends of local or national events. From the very beginning one of the main ideas of the promoters was to increase the quality and reach of live broadcasts, so SMP RDRC became the first racing series with its video production and remains so to this day. Russian Championship has four classes: Regional Series also have four classes divided by ET: The national record belongs to 4- time national champion Dmitry Samorukov: 6. 325 seconds at. It was set in a special record run in 2016 on Dodge Viper Doorslammer in Grozny, Chechen Republic at" Fort Grozny" racetrack. Dmitry Samorukov was the first Russian participant of the FIA European Championship on a newly built Chevrolet Camaro in the most competitive Promod class in 2019. After six stages of the competition,hetook10th of 38 places overall. Russian driver Dmitry Kapustin on Nissan Skyline GT-RR32 is holding the European record of AWD streetcars: 7. 182 | seconds at. The record was |
set in a qualifying run in Grozny, Chechen Republic at" Fort Grozny" racetrack in 2018. 1/ 2 mile races are also popular in Russia." Unlim 500+" is the main 1/ 2 mile race in Russia. It' s a supercar and sportscar festival where only 500+ hp cars are allowed( e. g. Nissan GT- R,McLaren720S, Lamborghini Aventador, Porsche 911, Ferrari 488, etc.). The national record on 1/ 2 mile distance also belongs to Dmitry Samorukov on Nissan GT- R R 35: 13. 305 seconds at. The record was set on a test and tune day at the" RDRC Racepark" track in 2020. Classes. There are hundreds of classes in drag racing, each with different requirements and restrictions on things such as weight, engine size, body style, modifications, and many others. NHRA and IHRA share some of these classes, but many are solely used by one sanctioning body or the other. The NHRA boasts over 200 classes, while the IHRA has fewer. Some IHRA classes have multiple sub- classes in them to differentiate by engine components and other features. There is even a class for aspiring youngsters, Junior Dragster, which typically uses an eighth- mile track, also favored by VW racers. In 1997, the FIA( cars) and UEM( bikes) began sanctioning drag racing in Europe with a fully established European Drag Racing Championship, in cooperation( and rules compliance) with NHRA. The major European drag strips include Santa Pod Raceway in Podington, England; Alastaro Circuit, Finland; Mantorp Park, Sweden; Gardermoen Raceway, Norway and the Hockenheimring in Germany. There is a somewhat arbitrary definition of what constitutes a" professional" class. The NHRA includes 5 pro classes; Top Fuel, Funny Car, Pro Stock, Pro Modified and Pro Stock Motorcycle. The FIA features a different set of 5 pro classes; Top Fuel, Top Methanol Dragster, Top Methanol Funny Car, Pro Modified and Pro Stock. Other sanctioning bodies have similarly different definitions. A partial list of classes includes: A complete listing of all classes can be found on the respective NHRA and IHRA official websites. The UEM also has a different structure of professional categories with Top Fuel Bike, Super Twin Top Fuel Bike, and Pro Stock Bike contested, leaving the entire European series with a total of 8 professional categories. To allow different cars to compete against each other, some competitions are raced on a handicap basis, with faster cars delayed on the starting line enough to theoretically even things up with the slower car. This may be based on rule differences between the cars in stock, super stock, and modified classes, or on a competitor' s chosen" dial- in" in bracket racing. For a list of drag racing world records in each class, see Dragstrip# Quarter mile times. Dial- in. A' dial- in' is a time the driver estimates it will take his or her car to cross the finish line, and is generally displayed on one or more windows so the starter can adjust the starting lights on the tree accordingly. The slower car will then get a head start equal to the difference in the | two dial- ins, so if |
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