geologic history of Earth: Time scales: A magnetic-polarity time scale for the stratigraphy of normal and reversed magnetic stripes can be constructed back as far as 280–260 million years ago, which is the age of the oldest extant segment of ocean floor.

geomagnetics, branch of geophysics concerned with all aspects of the Earth’s magnetic field, including its origin, variation through time, and manifestations in the form of magnetic poles, the remanent magnetization of rocks, and local or regional magnetic anomalies. The latter reflect the

geomagnetic field, magnetic field associated with Earth. It is primarily dipolar (i.e., it has two poles, the geomagnetic North and South poles) on Earth’s surface. Away from the surface the dipole becomes distorted. In the 1830s the German mathematician and astronomer Carl Friedrich Gauss studied

Southeast Asian arts: 19th–21st century: …using the ancient theory of geomancy (fengshui), with the city facing the Huong (Perfume) River and the Ngu Binh mountain protecting the imperial gates from evil spirits. It consisted of a series of simple rectangular one-story pavilions, laid out among trees inside a group of courts. These buildings were southern…

augury: …other marks on paper (geomancy), fire and smoke (pyromancy), the shoulder blades of animals (scapulimancy), entrails of sacrificed animals (haruspicy), or their livers, which were considered to be the seat of life (hepatoscopy).

feng shui, an ancient Chinese practice of orienting significant sites, buildings, and the spaces and objects within them in harmony with the flow of qi (also spelled ch’i). Qi (“breath” or “dragon’s breath”) is the vital life force, comparable to prana in Indian culture. Feng shui is rooted in the

rock: Rock mechanics: …of study is known as geotectonics.

John Geometres was a Byzantine poet, official, and monk, known for his short poems in classical metre. Geometres held the post of protospatharios (commander of the guards) at the Byzantine court and later was ordained priest. His poems, on both contemporary politics and religious subjects, are

Archimedes’ Lost Method: Bonaventura Cavalieri in his Geometria Indivisibilibus Continuorum Nova Quadam Ratione Promota (1635; “A Certain Method for the Development of a New Geometry of Continuous Indivisibles”). Cavalieri observed what happens when a hemisphere and its circumscribing cylinder are cut by the family of planes parallel to the base of the…

James Gregory: …and of the Hyperbola”) and Geometriae Pars Universalis (1668; “The Universal Part of Geometry”). In the former work he used a modification of the method of exhaustion of Archimedes (287–212/211 bce) to find the areas of the circle and sections of the hyperbola. In his construction of an infinite sequence…

Emil Artin: Artin’s books include Geometric Algebra (1957) and, with John T. Tate, Class Field Theory (1961). Most of his technical papers are found in The Collected Papers of Emil Artin (1965).

geometric distribution, in statistics, a discrete probability distribution that describes the chances of achieving success in a series of independent trials, each having two possible outcomes. The geometric distribution thus helps measure the probability of success after a given number of trials.

population ecology: Exponential and geometric population growth: …of organisms whose growth is geometric. In these species a population grows as a series of increasingly steep steps rather than as a smooth curve.

fat and oil processing: Isomerization reactions: …of natural oils has the cis configuration, in which hydrogen atoms lie on one side of a plane cutting through the double bond and alkyl groups lie on the other side. During hydrogenation some of the unsaturation is converted to the trans configuration, with like groups on opposite sides of…

mathematics: The Elements: …constructions and proofs of plane geometric figures: Book I deals with the congruence of triangles, the properties of parallel lines, and the area relations of triangles and parallelograms; Book II establishes equalities relating to squares, rectangles, and triangles; Book III covers basic properties of circles; and Book IV sets out…

mean: geometric mean of x1 and x2. The geometric mean of n numbers x1, x2, …, xn is defined to be the nth root of their product:

pottery: Central America: …was painted with black curvilinear geometric motifs, in contrast to their earlier rectilinear style. During the period of Montezuma I in the 15th century, designs became more naturalistic, and birds, fish, and plant forms were freely utilized. European motifs first appear after the conquest, and such techniques as tin glazing…

drafting: Perspective: Geometric perspective is a drawing method by which it is possible to depict a three-dimensional form as a two-dimensional image that closely resembles the scene as visualized by the human eye. The camera produces photographs with such resemblance. Images produced by the eye, the camera,…

allometry: …common example of allometry is geometric scaling, in which surface area is a function of body mass. In general, for organisms that preserve their basic shape as they vary in size, the organism’s linear dimensions vary as the 13 and their surface area as the 23 powers of their body…

mathematics: Numerical calculation: By correlating the geometric sequence of numbers a, a2, a3,…(a is called the base) and the arithmetic sequence 1, 2, 3,…and interpolating to fractional values, it is possible to reduce the problem of multiplication and division to one of addition and subtraction. To do this Napier chose a…

geometric series, in mathematics, an infinite series of the form a + ar + ar2 + ar3+⋯, where r is known as the common ratio. A simple example is the geometric series for a = 1 and r = 1/2, or 1 + 1/2 + 1/4 + 1/8 +⋯, which converges to a sum of 2 (or 1 if the first term is excluded). The Achilles

Geometric style, style of ancient Greek art, primarily of vase painting, that began about 900 bc and represents the last purely Mycenaean-Greek art form that originated before the influx of foreign inspiration by about 800 bc. Athens was its centre, and the growing moneyed population of new Greek

Colin Maclaurin: In his first work, Geometrica Organica; Sive Descriptio Linearum Curvarum Universalis (1720; “Organic Geometry, with the Description of the Universal Linear Curves”), Maclaurin developed several theorems similar to some in Newton’s Principia, introduced the method of generating conic sections (the circle, ellipse, hyperbola, and parabola) that bears his name,…

fat and oil processing: Isomerization reactions: …of natural oils has the cis configuration, in which hydrogen atoms lie on one side of a plane cutting through the double bond and alkyl groups lie on the other side. During hydrogenation some of the unsaturation is converted to the trans configuration, with like groups on opposite sides of…

mathematics: The precalculus period: …Cambridge, published in 1670 his Geometrical Lectures, a treatise that more than any other anticipated the unifying ideas of the calculus. In it he adopted a purely geometric form of exposition to show how the determinations of areas and tangents are inverse problems. He began with a curve and considered…

optics: Geometrical optics: An optical image may be regarded as the apparent reproduction of an object by a lens or mirror system, employing light as a carrier. An entire image is generally produced simultaneously, as by the lens in a camera,…

geometrid moth, (family Geometridae), any member of a group of moths (order Lepidoptera) that includes the species commonly known as pug, wave, emerald, and carpet moths. The larvae of geometrid moths are called by a variety of common names, including inchworm, cankerworm, looper, and measuring

geometrid moth, (family Geometridae), any member of a group of moths (order Lepidoptera) that includes the species commonly known as pug, wave, emerald, and carpet moths. The larvae of geometrid moths are called by a variety of common names, including inchworm, cankerworm, looper, and measuring

Gaspard Monge, count de Péluse: In Géométrie descriptive (1799; “Descriptive Geometry”), based on his lectures at the École Normale, he developed his descriptive method for representing a solid in three-dimensional space on a two-dimensional plane by drawing the projections—known as plans, elevations, and traces—of the solid on a sheet of paper.…

mathematics: Analytic geometry: Descartes’s La Géométrie appeared in 1637 as an appendix to his famous Discourse on Method, the treatise that presented the foundation of his philosophical system. Although supposedly an example from mathematics of his rational method, La Géométrie was a technical treatise understandable independently of philosophy. It…

topology: Fundamental group: Thurston’s conjecture implies the Poincaré conjecture, and in recognition of his work toward proving these conjectures, the Russian mathematician Grigori Perelman was awarded a Fields Medal at the 2006 International Congress of Mathematicians.

Lepidoptera: Annotated classification: Superfamily Geometroidea Almost 22,000 species; adults with abdominal tympana; some authorities classify each of the 3 major families as a separate superfamily. Family Geometridae (measuring worm, or inchworm, moths) Approximately 21,000 species, abundant worldwide; adults and larvae commonly very cryptic, resembling

geometry, the branch of mathematics concerned with the shape of individual objects, spatial relationships among various objects, and the properties of surrounding space. It is one of the oldest branches of mathematics, having arisen in response to such practical problems as those found in

graphics processing unit: …being referred to was a geometry transformation engine (GTE). Though the technology was still used to perform calculations, it was less powerful than a modern GPU. Many components of the GTE were integrated into the GPU when the technology came out. The 3-D add-in card (which some consider the first…

boron group element: Less-common compounds: …gallium, indium, and thallium are coordinated to five or six atoms. These compounds have structures of the following types, M again representing any boron group element, D any donor molecule, and X any halogen (again, the solid lines are bonds in the plane of the screen, the atoms so bonded…

geōmoroi, class of citizens in ancient Greek society. In 7th-century-bce Attic society, geōmoroi were freemen, generally peasant farm holders, lower on the social and political scale than the eupatridae, the aristocracy, but above the dēmiourgoi, the artisans. The geōmoroi were ineligible for any

geomorphic cycle, theory of the evolution of landforms. In this theory, first set forth by William M. Davis between 1884 and 1934, landforms were assumed to change through time from “youth” to “maturity” to “old age,” each stage having specific characteristics. The initial, or youthful, stage of

geomorphology, scientific discipline concerned with the description and classification of the Earth’s topographic features. A brief treatment of geomorphology follows. For full treatment, see geology: Geomorphology. Much geomorphologic research has been devoted to the origin of landforms. Such

kŏmungo, Korean long board zither that originated in the 7th century. The kŏmungo is about 150 cm (5 feet) long and has three movable bridges and 16 convex frets supporting six silk strings. The front plate of the instrument is made of paulownia wood and the back plate is made of chestnut wood.

pocket gopher, (family Geomyidae), any of 38 species of predominantly North and Central American rodents named for their large, fur-lined cheek pouches. The “pockets” open externally on each side of the mouth and extend from the face to the shoulders; they can be everted for cleaning. The lips can

ribbon worm: Within the genera Prostoma and Geonemertes, the species may be either dioecious (i.e., separate male and female animals) or hermaphroditic (i.e. male and female reproductive organs in one animal). All ribbon worms have the ability to regenerate lost or damaged parts of their bodies; some species actually break up and…

gaon, the title accorded to the Jewish spiritual leaders and scholars who headed Talmudic academies that flourished, with lengthy interruptions, from the 7th to the 13th century in Babylonia and Palestine. The chief concern of the geonim was to interpret and develop Talmudic Law and to safeguard

palm: Ecology: …palm and some species of Geonoma, they grow at elevations as high as 3,000 metres in the Andes. There are exceptions, however, for palms are also found in swamps or poorly drained areas (bussu palm, Mauritia, date palm, sago palm, raffia palm) or brackish estuaries and lagoons (nipa palm) or…

palm: Ecology: …forest floor (Asterogyne martiana and Geonoma cuneata, for example) are being used to study light relationships, especially as regards simple versus dissected leaves. These studies are promising but in their preliminary stages.

palm: Characteristic morphological features: …rarely be 3 (Areca triandra, Geonoma triandra, Nypa fruticans) or more numerous, ranging from 6 to 36 in Heterospathe, to more than 200 in such groups as Caryota, Phytelephas, and Veitchia. Sterile stamens may differ only slightly from fertile stamens, or they may consist of a filament alone without an…

skeleton: Skeletomusculature of arthropods: …sclerites of burrowing centipedes (Geophilomorpha) enable them to change their shape in an earthwormlike manner while preserving a complete armour of surface sclerites at all times. The marginal zones of the sclerites bear cones of sclerotization that are set in the flexible cuticle, thus permitting flexure in any direction…

skeleton: Skeletomusculature of arthropods: …sclerites of burrowing centipedes (Geophilomorpha) enable them to change their shape in an earthwormlike manner while preserving a complete armour of surface sclerites at all times. The marginal zones of the sclerites bear cones of sclerotization that are set in the flexible cuticle, thus permitting flexure in any direction…

geophone, trade name for an acoustic detector that responds to ground vibrations generated by seismic waves. Geophones—also called jugs, pickups, and tortugas—are placed on the ground surface in various patterns, or arrays, to record the vibrations generated by explosives in seismic reflection and

George Ferdinand Becker: …in the establishment of the Geophysical Laboratory of the Carnegie Institution of Washington, D.C. In 1896 Becker went to South Africa to study the gold and diamond fields, and in 1898–99 he served as geologist to the U.S. Army in the Philippines.

archaeology: Preliminary work: and magnetic fields (geophysical prospecting). A method of electrical prospecting had been developed in large-scale oil prospecting: this technique, based on the degree of electrical conductivity present in the soil, began to be used by archaeologists in the late 1940s and has since proved very useful. Magnetic methods…

Texas Instruments Incorporated (TI), American manufacturer of calculators, microprocessors, and digital signal processors with its headquarters in Dallas, Texas. The direct antecedent to the company was founded May 16, 1930, by John Clarence (“Doc”) Karcher and Eugene McDermott to provide

geophysics, major branch of the Earth sciences that applies the principles and methods of physics to the study of the Earth. A brief treatment of geophysics follows. For full treatment, see geology: Geophysics. Geophysics deals with a wide array of geologic phenomena, including the temperature

geopolitics, analysis of the geographic influences on power relationships in international relations. The word geopolitics was originally coined by the Swedish political scientist Rudolf Kjellén about the turn of the 20th century, and its use spread throughout Europe in the period between World

geopolitics, analysis of the geographic influences on power relationships in international relations. The word geopolitics was originally coined by the Swedish political scientist Rudolf Kjellén about the turn of the 20th century, and its use spread throughout Europe in the period between World

ocean current: Pressure gradients: …along a horizontal plane or geopotential surface, a surface perpendicular to the direction of the gravity acceleration. Horizontal gradients of pressure, though much smaller than vertical changes in pressure, give rise to ocean currents.

natural gas: Geopressured fluids and methane hydrates: Geopressured reservoirs exist throughout the world in deep, geologically young sedimentary basins in which the formation fluids (which usually occur in the form of a brine) bear a part of the overburden load. The fluid pressures can become quite high,…

stingless bee: Natural history and life cycle: A material known as geoprolis, made of mud and tree resin mixed with saliva and wax, is used for nest building, along with cerumen, a substance created by mixing collected resin with self-secreted saliva and wax. Some species create elaborate entrance pipes to their hives, which may serve as…

parrot: For decades the night parrot, or night parakeet (Geopsittacus occidentalis), of Australia was thought to be extinct, until a dead one was found in 1990. It feeds at night on spinifex grass seeds and dozes under a tussock by day. Its nest is a twig platform in a…

George II was the king of Great Britain and elector of Hanover from 1727 to 1760. Although he possessed sound political judgment, his lack of self-confidence caused him to rely heavily on his ministers, most notable of whom was Sir Robert Walpole. George Augustus was the only son of the German

George IV was the king of the United Kingdom of Great Britain and Ireland and king of Hanover from January 29, 1820, to June 26, 1830. He served as the sovereign de facto from February 5, 1811, when he became regent for his father, George III, who suffered from mental illness. The eldest son of

Büchner Prize, prestigious German prize established in 1923 by the government of Volksstaat Hessen (state of Hesse, now in Hessen Land [state]) to honour native son Georg Büchner, a noted dramatist. From its inception to 1950 the prize was awarded to a range of Hessian visual artists, writers,

George I was the elector of Hanover (1698–1727) and the first Hanoverian king of Great Britain (1714–27). George Louis of Brunswick-Lüneburg was the son of Ernest Augustus, elector of Hanover, and Sophia of the Palatinate, a granddaughter of King James I of England. George married his cousin Sophia

George William was the elector of Brandenburg (from 1619) through much of the Thirty Years’ War. Though a Calvinist, George William was persuaded by his Roman Catholic adviser Adam von Schwarzenberg to stay out of the struggle between the Holy Roman emperor and the German Protestant princes. His

George III was the king of Great Britain and Ireland (1760–1820) and elector (1760–1814) and then king (1814–20) of Hanover, during a period when Britain won an empire in the Seven Years’ War but lost its American colonies and then, after the struggle against Revolutionary and Napoleonic France,

University of Göttingen, leading public research institution in Göttingen,Germany. The university was founded by George Augustus or George II, king of Great Britain and elector and duke of Hanover. It was officially inaugurated in 1737, though academic lectures had commenced in 1734. By the

Büchner Prize, prestigious German prize established in 1923 by the government of Volksstaat Hessen (state of Hesse, now in Hessen Land [state]) to honour native son Georg Büchner, a noted dramatist. From its inception to 1950 the prize was awarded to a range of Hessian visual artists, writers,

George was the king of Bohemia from 1458. As head of the conservative Utraquist faction of Hussite Protestants, he established himself as a power when Bohemia was still under Habsburg rule, and he was thereafter unanimously elected king by the estates. A nationalist and Hussite king of a prosperous

John F. Kennedy, Jr.: Public prominence, George magazine, marriage, and death: In 1995 Kennedy launched George, a glossy political magazine named after the first U.S. president, George Washington. The magazine became known for its pop culture approach to politics. Many issues featured covers with celebrities dressed as Washington or other early American figures such as Betsy Ross. As editor in…

George, is a town in the Western Cape province, South Africa. The town lies distantly east of Cape Town and immediately inland from the Indian Ocean. It was founded in 1811 as the first British settlement in the Cape Colony and named after King George III, as was George Peak nearby. Hops, not

nuclear weapon: The weapons are tested: …Pacific, a test explosion named George had successfully used a fission bomb to ignite a small quantity of deuterium and tritium. The original purpose of George had been to confirm the burning of these thermonuclear fuels (about which there had never been any doubt), but with the new conceptual understanding…

Michael Shannon: Playing Elvis, Estragon, and George Jones: …display his musical talent in George & Tammy, a Showtime miniseries about the rocky romance of country music legends George Jones and Tammy Wynette (played by Jessica Chastain). An amateur musician who leads a rock band called Corporal, Shannon performed his own vocals in his role as Jones. In an…

Music lovers in more than a dozen states along the Eastern Seaboard in the 1950s tuned in to “the Sound of the Hound,” George (“Hound Dog”) Lorenz, who broadcast on 50,000-watt WKBW in Buffalo, New York. Lorenz began in Buffalo radio in the late 1940s; in 1953 he moved to Cleveland, Ohio, where the

William, prince of Wales: Marriage and children: The couple’s first son, Prince George Alexander Louis of Cambridge, was born on July 22, 2013. They subsequently had a daughter, Princess Charlotte Elizabeth Diana of Cambridge (born May 2, 2015), and a second son, Prince Louis Arthur Charles of Cambridge (born April 23, 2018).

George IV was the king of the United Kingdom of Great Britain and Ireland and king of Hanover from January 29, 1820, to June 26, 1830. He served as the sovereign de facto from February 5, 1811, when he became regent for his father, George III, who suffered from mental illness. The eldest son of

George II was the king of Great Britain and elector of Hanover from 1727 to 1760. Although he possessed sound political judgment, his lack of self-confidence caused him to rely heavily on his ministers, most notable of whom was Sir Robert Walpole. George Augustus was the only son of the German

This forceful, almost hortatory essay by George Bernard Shaw first appeared in the 13th edition of the Encyclopædia Britannica (1926), the same year Shaw received the Nobel Prize in Literature “for his work which is marked by both idealism and humanity, its stimulating satire often being infused

Gracie Allen: …television with the debut of The George Burns and Gracie Allen Show (1950–58). It portrayed the daily life of the married couple, and Burns regularly broke through television’s “fourth wall” by stepping out of a scene to address the audience directly.

George Cross, a British civilian and military decoration, instituted in 1940 by King George VI for “acts of the greatest heroism or of the most conspicuous courage in circumstances of extreme danger.” The award, which can be conferred posthumously, is usually given to civilians, although it can be

Molière: Harassment by the authorities: His second play of 1668, George Dandin, often dismissed as a farce, may be one of Molière’s greatest creations. It centers on a fool, who admits his folly while suggesting that wisdom would not help him because, if things in fact go against us, it is pointless to be wise.…

George Eastman: …in Rochester, now known as George Eastman House, has become a renowned archive and museum of international photography as well as a popular tourist site.

Hale Telescope, one of the world’s largest and most powerful reflecting telescopes, located at the Palomar Observatory, Mount Palomar, Calif. It was financed by the Rockefeller Foundation, and the first observations were made in 1949. The telescope was named in honour of the noted American

Peabody Award, any of the awards administered annually by the University of Georgia’s Grady College of Journalism and Mass Communication in recognition of outstanding public service and achievement in electronic media. Recipients are organizations and individuals involved in the production or

Newberg: It is the seat of George Fox University, established in 1885 as Friends Pacific Academy; the future American president Herbert Hoover was in the first graduating class of 1888. Hoover-Minthorn House (1881), where the orphaned Hoover lived with his uncle, has been restored. Nearby Champoeg State Heritage Area, once the…

George V was the king of the United Kingdom from 1910 to 1936, the second son of Prince Albert Edward, later King Edward VII. He served in the navy until the death (1892) of his elder brother, Prince Albert Victor, brought the need for more specialized training as eventual heir to the throne.

Texas A&M University: The George Bush Presidential Library and Museum, commemorating the 41st U.S. president, is on the College Station campus. Enrollment at College Station is approximately 44,500 students; more than 90,000 are enrolled in the system as a whole.

Martin Scorsese: Films of the 2010s: Shutter Island, Hugo, and The Wolf of Wall Street: …another of his musical documentaries, George Harrison: Living in the Material World (2011), which examined the life of the former Beatle. Scorsese branched out further into television as the executive producer of Boardwalk Empire (2010–14), an HBO drama series about gangsters in Atlantic City during Prohibition. He also directed the…

George I was the elector of Hanover (1698–1727) and the first Hanoverian king of Great Britain (1714–27). George Louis of Brunswick-Lüneburg was the son of Ernest Augustus, elector of Hanover, and Sophia of the Palatinate, a granddaughter of King James I of England. George married his cousin Sophia

George I was the king of the Greeks whose long reign (1863–1913) spanned the formative period for the development of Greece as a modern European state. His descendants occupied the throne until the military coup d’état of 1967 and eventual restoration of the republic in 1973. Born Prince

George I was the king of the Greeks whose long reign (1863–1913) spanned the formative period for the development of Greece as a modern European state. His descendants occupied the throne until the military coup d’état of 1967 and eventual restoration of the republic in 1973. Born Prince

George II was the king of Great Britain and elector of Hanover from 1727 to 1760. Although he possessed sound political judgment, his lack of self-confidence caused him to rely heavily on his ministers, most notable of whom was Sir Robert Walpole. George Augustus was the only son of the German

George II was the king of Greece from September 1922 to March 1924 and from October 1935 until his death. His second reign was marked by the ascendancy of the military dictator Ioannis Metaxas. The eldest son of King Constantine I, George was excluded from the succession during World War I for his

George II was the duke of Saxe-Meiningen, theatrical director and designer who developed many of the basic principles of modern acting and stage design. A wealthy aristocrat and head of a small German principality, Saxe-Meiningen early studied art and in 1866 established his own court theatre

George III was the king of Great Britain and Ireland (1760–1820) and elector (1760–1814) and then king (1814–20) of Hanover, during a period when Britain won an empire in the Seven Years’ War but lost its American colonies and then, after the struggle against Revolutionary and Napoleonic France,

Southwark: The George (built in 1676), now owned by the National Trust, is the last surviving galleried inn in London.

George IV was the king of the United Kingdom of Great Britain and Ireland and king of Hanover from January 29, 1820, to June 26, 1830. He served as the sovereign de facto from February 5, 1811, when he became regent for his father, George III, who suffered from mental illness. The eldest son of

Weddell Sea, large embayment of the Antarctic coastline that forms a deep southward extension of the Southern Ocean. Centering at about 73° S 45° W, the Weddell Sea is bounded on the west by the Antarctic Peninsula of West Antarctica, on the east by Coats Land of East Antarctica, and on the extreme

George Lopez: The result was George Lopez (2002–07), which featured Lopez as a version of himself and drew on his life in its depictions of a Mexican American family. Lopez also served as a producer and writer on the show, which was eventually syndicated. He released the album El Mas…

George I was the elector of Hanover (1698–1727) and the first Hanoverian king of Great Britain (1714–27). George Louis of Brunswick-Lüneburg was the son of Ernest Augustus, elector of Hanover, and Sophia of the Palatinate, a granddaughter of King James I of England. George married his cousin Sophia

Joel Grey: …title role in the musical George M! (1968), about the entertainer George M. Cohan, and that performance earned him a Tony Award nomination. Grey later played Cohan in a 1970 TV adaptation of the play. The 1972 film version of Cabaret won eight Academy Awards, one of which (for best…

George Mason University, public, coeducational institution of higher learning in Fairfax, Virginia, U.S. It consists of 12 colleges and schools offering a variety of undergraduate and graduate degrees. Several of its graduate programs have been recognized nationally for excellence and distinction