Gravesend, town, Gravesham district, administrative and historic county of Kent, southeastern England. It lies on the right bank of the River Thames, downstream from London, and is the district administrative centre. The discovery of the Swanscombe skull near Gravesend dates early settlement in the

Gravesham, borough (district), administrative and historic county of Kent, southeastern England. Its centre is the town of Gravesend, but it includes a section of the south bank of the River Thames above and below the town, and it runs inland to the crest of the chalk hills (North Downs) that

African art: Horn of Africa: …also of southern Ethiopia, make tombstones of like height, ornamented with engravings filled in with red or black, sometimes showing the deceased in rough relief. Similarly shaped gravestones—sometimes plain, sometimes adorned with decoration—occur in Somalia.

Stone Age: Périgordian: …points with blunted backs, called Gravette points and characteristic of the Upper Périgordian, were evolved from the Châtelperron type. In the final stage of the Upper Périgordian, tanged Font Robert points and diminutive multiangle gravers, known as the Noailles burin, are found. A number of small sculptured human torsos depicting…

history of the Low Countries: Upper Paleolithic (35,000–10,000 bp): Aurignacian, Gravettien (upper Perigordian), and Magdalenian assemblages found in the Ardennes caves represent the northernmost fringes of the inhabited zone of Europe until about 13,000 bp. The open site of Maisières Canal in Hainaut province, Belgium, is exceptional for its preservation of glacial fauna (from about…

cemetery, place set apart for burial or entombment of the dead. Reflecting geography, religious beliefs, social attitudes, and aesthetic and sanitary considerations, cemeteries may be simple or elaborate—built with a grandeur that overshines the community of the living. They may also be regarded as

Neil Gaiman: …to literature for children for The Graveyard Book (2008), the macabre yet sweet tale of an orphan raised by a cemetery full of ghosts. In the ostensibly adult novel The Ocean at the End of the Lane (2013), a man reflects on a series of supernatural traumas sustained during his…

The Graveyard by the Sea, poem by Paul Valéry, written in French as “Le Cimetière marin” and published in 1922 in the collection Charmes; ou poèmes. The poem, set in the cemetery at Sète (where Valéry himself is now buried), is a meditation on death. At first the narrator observes the calm sea

graveyard school, genre of 18th-century British poetry that focused on death and bereavement. The graveyard school consisted largely of imitations of Robert Blair’s popular long poem of morbid appeal, The Grave (1743), and of Edward Young’s celebrated blank-verse dramatic rhapsody Night Thoughts

spatial disorientation: …is known as the “graveyard spin.” The “graveyard spiral” results when the sensation of turning is lost in a banked turn. Because the pilot’s instruments show that he is losing altitude, he may pull back on the stick and add power, thus inducing a spiral motion. The oculogyral illusion…

spatial disorientation: ” The “graveyard spiral” results when the sensation of turning is lost in a banked turn. Because the pilot’s instruments show that he is losing altitude, he may pull back on the stick and add power, thus inducing a spiral motion. The oculogyral illusion is created by…

Charles Gravier, count de Vergennes was a French foreign minister who fashioned the alliance with the North American colonists that helped them throw off British rule in the American Revolution; at the same time, he worked, with considerable success, to establish a stable balance of power in

gravimeter, sensitive device for measuring variations in the Earth’s gravitational field, useful in prospecting for oil and minerals. In one form, it consists of a weight suspended from a spring; variations in gravity cause variations in the extension of the spring. A number of different mechanical

gravimetric analysis, a method of quantitative chemical analysis in which the constituent sought is converted into a substance (of known composition) that can be separated from the sample and weighed. The steps commonly followed in gravimetric analysis are (1) preparation of a solution containing a

Gravina in Puglia, walled town, Puglia (Apulia) regione, southern Italy. The town’s cathedral and the castle of the Orsini family are notable local monuments, and there are numerous cave dwellings in the locality. The town also has museums of local costumes and of archaeology and pottery. Local

Italian literature: The world of learning: Literary criticism also attracted attention; Gian Vincenzo Gravina, Vico, Maffei, Muratori, and several others, while continuing to advocate the imitation of the classics, realized that such imitation should be cautious and thus anticipated critical standpoints that were later to come into favour.

soursop, (Annona muricata), tree of the custard apple family (Annonaceae) and its large edible fruits. Native to the American tropics, the tree has been widely introduced in the Old World tropics. The fruit’s juicy, fibrous, white flesh, which combines the flavours of mango and pineapple, can be

celestial mechanics: Newton’s laws of motion: …was the same as the gravitational force attracting objects to Earth. Newton further concluded that the force of attraction between two massive bodies was proportional to the inverse square of their separation and to the product of their masses, known as the law of universal gravitation. Kepler’s laws are derivable…

gravity, in mechanics, the universal force of attraction acting between all matter. It is by far the weakest known force in nature and thus plays no role in determining the internal properties of everyday matter. On the other hand, through its long reach and universal action, it controls the

gravitational constant (G), physical constant denoted by G and used in calculating the gravitational attraction between two objects. In Newton’s law of universal gravitation, the attractive force between two objects (F) is equal to G times the product of their masses (m1m2) divided by the square of

Newton’s law of gravitation, statement that any particle of matter in the universe attracts any other with a force varying directly as the product of the masses and inversely as the square of the distance between them. In symbols, the magnitude of the attractive force F is equal to G (the

gravitational constant (G), physical constant denoted by G and used in calculating the gravitational attraction between two objects. In Newton’s law of universal gravitation, the attractive force between two objects (F) is equal to G times the product of their masses (m1m2) divided by the square of

gravity: Potential theory: …used for finding the resulting gravitational field. The main progress in classical gravitational theory after Newton was the development of potential theory, which provides the mathematical representation of gravitational fields. It allows practical as well as theoretical investigation of the gravitational variations in space and of the anomalies due to…

celestial mechanics: Newton’s laws of motion: …was the same as the gravitational force attracting objects to Earth. Newton further concluded that the force of attraction between two massive bodies was proportional to the inverse square of their separation and to the product of their masses, known as the law of universal gravitation. Kepler’s laws are derivable…

locomotion: Gravitational gliding: Gravitational gliding is equivalent to parachuting. Because the expanded lateral surface of the body increases the wind resistance against the body, the speed of falling is reduced. The directions of gliding can be controlled by adjusting the surface area—to curve to the right,…

celestial mechanics: Newton’s laws of motion: …was the same as the gravitational force attracting objects to Earth. Newton further concluded that the force of attraction between two massive bodies was proportional to the inverse square of their separation and to the product of their masses, known as the law of universal gravitation. Kepler’s laws are derivable…

gravitational lens, matter that through the bending of space in its gravitational field alters the direction of light passing nearby. The effect is analogous to that produced by a lens. One of the most remarkable predictions of Einstein’s theory of general relativity is that gravity bends light.

gravitational lens, matter that through the bending of space in its gravitational field alters the direction of light passing nearby. The effect is analogous to that produced by a lens. One of the most remarkable predictions of Einstein’s theory of general relativity is that gravity bends light.

gravity: Gravitational fields and the theory of general relativity: Gravitational mass is determined by the strength of the gravitational force experienced by the body when in the gravitational field g. The Eötvös experiments therefore show that the ratio of gravitational and inertial mass is the same for different substances.

gravitational microlensing, brightening of a star by an object passing between the star and an observer. Since 2004 many extrasolar planets have been found through gravitational microlensing, including several so-called free-floating planets that do not orbit any star. This technique depends on an

mechanics: Falling bodies and uniformly accelerated motion: The gravitational potential energy is given by

gravitational wave, the transmission of variations in the gravitational field as waves. According to general relativity, the curvature of space-time is determined by the distribution of masses, while the motion of masses is determined by the curvature. In consequence, variations of the

Schwarzschild radius, the radius below which the gravitational attraction between the particles of a body must cause it to undergo irreversible gravitational collapse. This phenomenon is thought to be the final fate of the more massive stars (see black hole). The Schwarzschild radius (Rg) of an

astronomy: Testing relativity: …predicted by Einstein was the gravitational redshift. Light coming from a compact massive object should be slightly redshifted; that is, the light should have a longer wavelength. Measuring this was a delicate business, as the expected shift was small and could easily be masked by other effects. Attempts to measure…

astronomy: Testing relativity: …predicted by Einstein was the gravitational redshift. Light coming from a compact massive object should be slightly redshifted; that is, the light should have a longer wavelength. Measuring this was a delicate business, as the expected shift was small and could easily be masked by other effects. Attempts to measure…

vadose zone: …influence of gravity, is called vadose water, or gravitational water.

gravitational wave, the transmission of variations in the gravitational field as waves. According to general relativity, the curvature of space-time is determined by the distribution of masses, while the motion of masses is determined by the curvature. In consequence, variations of the

subatomic particle: Testing supersymmetry: zino, gluino, and gravitino, respectively. If they indeed exist, all these new supersymmetric particles must be heavy to have escaped detection so far.

graviton, postulated quantum that is thought to be the carrier of the gravitational field. It is analogous to the well-established photon of the electromagnetic field. Gravitons, like photons, would be massless, electrically uncharged particles traveling at the speed of light. Since gravitons would

angiosperm: Root systems: …that grows vertically downward (positive geotropism). From the taproot are produced smaller lateral roots (secondary roots) that grow horizontally or diagonally. These secondary roots further produce their own smaller lateral roots (tertiary roots). Thus, many orders of roots of descending size are produced from a single prominent root, the taproot.…

Sandra Bullock: …starred with George Clooney in Gravity, an acclaimed drama about astronauts struggling to survive after their spacecraft has been destroyed; Bullock earned an Oscar nomination for her performance. She then voiced the villainous Scarlett Overkill in the animated comedy Minions and depicted the struggles of an American political strategist guiding…

gravity, in mechanics, the universal force of attraction acting between all matter. It is by far the weakest known force in nature and thus plays no role in determining the internal properties of everyday matter. On the other hand, through its long reach and universal action, it controls the

John Mayer: …solo rock performance (for “Gravity,” from the 2008 live album Where the Light Is). That same year Mayer released the album Battle Studies. Although it sold well, it was somewhat overshadowed by Mayer’s increasingly tabloid-friendly public persona; in contrast to his heartfelt, skillfully crafted music, he had become known…

deep-sea trench: Origin of deep-sea trenches: These negative gravity anomalies are interpreted to mean that the segments of the lithosphere (that is, the crust and upper mantle comprising the rigid, outermost shell of the Earth) that underlie trenches are being forced down against buoyant isostatic forces.

mineral processing: Gravity separation: Gravity methods use the difference in the density of minerals as the concentrating agent.

gravity dam, a concrete or masonry dam so proportioned that it will resist overturning and sliding forces by its own weight. Concrete gravity dams usually run in a straight line across a broad valley and resist the horizontal thrust of the retained water entirely by their own weight. The three main

Big Ben: …principal contribution was a novel gravity escapement that imparted unprecedented accuracy to the clock. In a pendulum clock an escape wheel is allowed to rotate through the pitch of one tooth for each double swing of the pendulum and to transmit an impulse to the pendulum to keep it swinging.…

fault: Normal dip-slip faults are produced by vertical compression as Earth’s crust lengthens. The hanging wall slides down relative to the footwall. Normal faults are common; they bound many of the mountain ranges of the world and many of the rift valleys found along spreading margins…

filtration: Filter types: The gravity filter is the oldest and simplest type. Gravity sand-bed filters installed in city water plants are among the most common filters. Such filters involve the use of tanks that usually are constructed of concrete. At the bottom of the tank is a grating or…

ocean basin: Exploration of the ocean basins: The resulting gravity map provides comprehensive coverage of the ocean surface on a 5′-by-5′ grid that depicts five nautical miles on each side at the Equator). Coverage as complete as this is not available from echo soundings made from ships. Because the gravity field at the ocean…

gravimeter, sensitive device for measuring variations in the Earth’s gravitational field, useful in prospecting for oil and minerals. In one form, it consists of a weight suspended from a spring; variations in gravity cause variations in the extension of the spring. A number of different mechanical

Gravity Probe B (GP-B), U.S. spacecraft, launched April 20, 2004, into polar orbit, that tested Einstein’s general theory of relativity. Specifically, it proved the existence of both frame-dragging—a very subtle phenomenon in which the rotation of a body (in this case, Earth) slowly drags the

human ear: Vestibule: …saccule, are known as the otolith organs. Because they respond to gravitational forces, they are also called gravity receptors. Each sac has on its inner surface a single patch of sensory cells called a macula, which is about 2 mm (0.08 inch) in diameter. The macula monitors the position of…

Gravity Recovery and Climate Experiment (GRACE), U.S.-German Earth-mapping mission consisting of twin spacecraft GRACE 1 and 2 (nicknamed Tom and Jerry after the cartoon characters). GRACE 1 and 2 were launched on March 17, 2002. By tracking the precise distance between the two spacecraft and their

Gravity Recovery and Interior Laboratory (GRAIL), U.S. space mission that consisted of two spacecraft, Ebb and Flow, designed to map the Moon’s gravitational field. GRAIL was launched from Cape Canaveral, Florida, on September 10, 2011. To conserve fuel, the spacecraft traveled very slowly, taking

roller coaster: Development in the United States: …early 19th century, the so-called Mauch Chunk Switchback Railway in Pennsylvania became the prototype for roller coasters in the United States, the country most associated with thrill rides. Its origins were in Gravity Road, which mining company entrepreneur Josiah White built in 1827 to haul coal from the mines at…

mineral processing: Gravity separation: Gravity methods use the difference in the density of minerals as the concentrating agent.

cave: Tectonic caves: …apart, the key mechanism is gravity sliding. The optimum setting for the development of tectonic caves occurs where massive rocks dip gently to the sides of ridges or mountains. The presence of shale layers between beds of massive sandstone can act as a lubricating layer and facilitate mechanical slippage. Gravity…

petroleum production: Gravity and magnetic surveys: Although gravity at Earth’s surface is very nearly constant, it is slightly greater where dense rock formations lie close to the surface. Gravitational force, therefore, increases over the tops of anticlinal (arch-shaped) folds and decreases over the tops of salt domes.…

harbours and sea works: Gravity walls: The solution initially favoured, and indeed predominant for many years, was that of the simple gravity retaining wall, capable of holding land and water apart, so to speak, through a combination of its own mass with the passive resistance of the ground forming…

gravitational wave, the transmission of variations in the gravitational field as waves. According to general relativity, the curvature of space-time is determined by the distribution of masses, while the motion of masses is determined by the curvature. In consequence, variations of the

wave: Physical characteristics of surface waves: Surface gravity waves in which gravity is the dominant force have wavelengths greater than approximately 10 cm (4 inches). In the intermediate length range, both restoring mechanisms are important.

katabatic wind, wind that blows down a slope because of gravity. It occurs at night, when the highlands radiate heat and are cooled. The air in contact with these highlands is thus also cooled, and it becomes denser than the air at the same elevation but away from the slope; it therefore begins to

Gravity’s Rainbow, novel by Thomas Pynchon, published in 1973. The sprawling narrative comprises numerous threads having to do either directly or tangentially with the secret development and deployment of a rocket by the Nazis near the end of World War II. Lieut. Tyrone Slothrop is an American

centre of gravity, in physics, an imaginary point in a body of matter where, for convenience in certain calculations, the total weight of the body may be thought to be concentrated. The concept is sometimes useful in designing static structures (e.g., buildings and bridges) or in predicting the

spaceflight: Planetary: This gravity-assist, or slingshot, technique has been used numerous times to send planetary probes to their destinations. For example, the Galileo probe during its six-year voyage to Jupiter swung by Venus once and Earth twice in order to reach its ultimate target in 1995.

conveyor: Gravity-roller conveyors consist of a series of parallel rollers fastened to a metal frame supported at intervals. The frame can be inclined slightly for gravity flow, but objects and packages may also be rolled along manually. Gravity-wheel conveyors are similar but consist of skate wheels…

conveyor: Gravity-wheel conveyors are similar but consist of skate wheels instead of rollers and are usually used for lighter loads. Live-roller conveyors are gravity-roller conveyors that are power driven by means of a belt snubbed against the underpart of the rolls or by a chain driving…

gastronomy: Scandinavian: …ways; a favourite appetizer is gravlax, salmon marinated in salt and dill and accompanied by a mustard sauce. Swedish pancakes are popular and are served with lingonberries or fruit preserves.

gravure printing, photomechanical intaglio process in which the image to be printed consists of depressions or recesses on the surface of the printing plate. The process is the reverse of relief printing, in which the image is raised from the surface of the plate. The printer forms the image by

rotogravure printing: …transfer by means of a gravure screen; this is a grid of closely intersecting lines that create thousands of tiny squares on the plate, which will in turn react differentially to an etching bath after the plate has been exposed to light through the positive film. The varying depths of…

Joan Tower: …first woman to receive the Grawemeyer Award. She also wrote concertos for clarinet (1988), oboe (1989), flute (1989), piano (1985 and 1996), violin (1991), percussion (2001), and bassoon (2013). The acclaimed Made in America was first performed in 2005, and it later won a Grammy Award for best classical contemporary…

gray, unit of absorbed dose of ionizing radiation, defined in the 1980s by the International Commission on Radiation Units and Measurements. One gray is equal approximately to the absorbed dose delivered when the energy per unit mass imparted to matter by ionizing radiation is one joule per

Western Electric Company Inc., American telecommunications manufacturer that throughout most of its history was under the control of the American Telephone and Telegraph Company (AT&T). It was the major manufacturer of a broad range of telephone equipment: telephones, wires and cables, electronic

arsenic: …periodic table), existing in both gray and yellow crystalline forms.

bichir: At least one species, the Senegal or gray bichir (P. senegalus), is capable of using its pectoral fins to propel itself across land for short distances—an adaptation that may have evolved to help the species move between temporary ponds that were drying up or hunt terrestrial insects.

gray birch, (Betula populifolia), slender ornamental tree of the family Betulaceae, found in clusters on moist sites in northeastern North America. See also birch. Rarely 12 metres (40 feet) tall, it is covered almost to the ground with flexible branches that form a narrow pyramidal crown. The

butcherbird: A familiar species is the gray butcherbird (C. torquatus).

catbird: The North American catbird (Dumetella carolinensis), of the family Mimidae (order Passeriformes), is 23 cm (9 inches) long and is gray, with a black cap. It frequents gardens and thickets. The black catbird (Melanoptila glabrirostris) is found in coastal Yucatán.

Tris Speaker was an American professional baseball player and manager who spent his 22-year career (1907–28) primarily with the Boston Red Sox and the Cleveland Indians. Speaker and Ty Cobb are generally considered the two greatest players of this period. Speaker was perhaps the best centre fielder

Father Joseph was a French mystic and religious reformer whose collaboration with Cardinal de Richelieu (the “Red Eminence”) gave him powers akin to those of a foreign minister, especially during Richelieu’s ambitious campaign to finance France’s participation in what became known as the Thirty

Friedrich von Holstein was the most influential German foreign policymaker from 1890 to 1909, during the reign of Emperor William II (Kaiser Wilhelm II), after the departure of Chancellor Otto von Bismarck. A member of the Foreign Office in Berlin uninterruptedly from 1876, he never became foreign

Europe: Soils: …known as degraded chernozems and gray forest soils. At best, chestnut soils—some needing only water to be productive—and, at worst, solonetzic (highly saline) soils cover areas of increasing aridity eastward of Ukraine to the Ural River. Lastly, in southern Europe, where the countryside is fragmented by mountains, plateaus, and hills,…

opossum: Opossums of Latin America: The seven species of gray four-eyed opossum (Philander) and the brown four-eyed, or rat-tailed, opossum (Metachirus nudicaudatus) get their name from the large pale spots over each eye. One species (Philander opossum) of the gray four-eyed opossum and the brown four-eyed opossum are found in both Central and South America;…

opossum: Opossums of Latin America: The seven species of gray four-eyed opossum (Philander) and the brown four-eyed, or rat-tailed, opossum (Metachirus nudicaudatus) get their name from the large pale spots over each eye. One species (Philander opossum) of the gray four-eyed opossum and the brown four-eyed opossum are found in both Central and South America;…

gray fox, (Urocyon cinereoargenteus), grizzled, gray-furred New World fox of the family Canidae. It is found in forested, rocky, and brush-covered country from Canada to northern South America. Distinguished by the reddish colour on its neck, ears, and legs, the gray fox grows to a length of about

Native Dancer, (foaled 1950), American racehorse (Thoroughbred) who won 21 of 22 starts and achieved widespread popularity as the first outstanding horse whose major victories were seen on national television. Sired by Polynesian out of Geisha, the gray colt was undefeated in nine races as a

Anser, bird genus of the family Anatidae (order Anseriformes). For a general discussion of the genus, see goose; for A. Albifrons, see white-fronted goose; for A. anser, see greylag; for A. caerulescens, see snow

hairstreak: …larva of the North American gray hairstreak (Strymon melinus), which bores into fruit and seeds.

grouse: …Old World member is the black grouse (Lyrurus tetrix), of Wales, Scotland, Scandinavia, and north-central Europe; a related form (L. mlokosiewiczi) occurs in the Caucasus. The male, known as blackcock, may be 55 cm (22 inches) long and weigh almost 2 kg (about 4 pounds). He is iridescent blue-black, with…

heron: …the similar but slightly smaller gray, or common, heron (A. cinerea), widespread in the Old World. Largest of all is the goliath heron (A. goliath) of Africa, a 150-cm (59-inch) bird with a reddish head and neck. The purple heron (A. purpurea) is a darker and smaller Old World form.

cast iron: …cast iron is either so-called gray iron or white iron, the colours shown by fracture. Gray iron contains more silicon and is less hard and more machinable than is white iron. Both are brittle, but a malleable cast iron produced by a prolonged heat treatment was developed in France in…

aardwolf, (Proteles cristatus), insectivorous carnivore that resembles a small striped hyena. The shy, mainly nocturnal aardwolf lives on the arid plains of Africa. There are two geographically separate populations, one centred in South Africa and the other in East Africa. The aardwolf, whose name

jay: The gray jay (Perisoreus canadensis) inhabits the northern reaches of the United States and most of Canada.

chicken: …there is evidence that the gray jungle fowl (G. sonneratii) of southern India and other jungle fowl species, also members of Gallus, may have contributed to the bird’s ancestry. There is some debate about what the chicken’s scientific name should be. Although many taxonomists and ornithologists consider it as a…

kangaroo: Descriptions of selected species: Gray kangaroos can clear more than 9 metres (30 feet) at a bound—13.5 metres has been recorded—and can attain a speed of 55 km/hr (kilometres per hour; 34 mph [miles per hour]). Research has revealed a remarkable advantage to bipedal hopping. Although at low speeds…

langur: The gray, or Hanuman, langur (S. entellus) of the Indian subcontinent is almost black when newborn and gray, tan, or brown as an adult. Regarded as sacred in Hinduism, it spends a good deal of time on the ground and roams at will in villages and temples of…

Chris Evans: …2022 include the spy thriller The Gray Man, in which he portrayed a villainous former CIA agent.

brain: …a convoluted (wrinkled) layer of gray matter. The degree of convolution is partly dependent on the size of the body. Small mammals (e.g., lesser anteater, marmoset) generally have smooth brains, and large mammals (e.g., whale, elephant, dolphin) generally have highly convoluted ones.

gray mold rot, disease of plants growing in humid areas that is caused by fungi in the genus Botrytis, usually B. cinerea. Most vegetables, fruits, flowers, and woody plants are susceptible. The disease primarily affects flowers and buds, though infections on fruits, leaves, and stems can occur.