POLE encyclopedia topics

pole, in electricity and magnetism, point where electric or magnetic force appears to be concentrated. A single electric charge located at a point is sometimes referred to as an electric monopole. An electric dipole consists of two equal and opposite charges separated by a distance. Some molecules, although electrically neutral as a whole, do not have their charges distributed symmetrically, so that the separation of the centers of positive and negative charge constitutes an electric dipole; such molecules are called polar molecules. In calculating the electric potential at a distance r from an electric dipole, it is found that it varies principally as 1/r², while the potential around a single charge varies as 1/r. More complex arrangements of charges may have potentials whose principal term contains a higher power of the distance r. A charge configuration for which the principal term of the potential varies as 1/r³ is called an electric quadrupole; similarly, an octupole is characterized by a potential varying as 1/r⁴, a 16-pole by 1/r⁵, and so forth. In magnetism, poles may be defined in an analogous way, so that an ordinary bar magnet with a north pole at one end and a south pole at the other constitutes a magnetic dipole. The potential energy associated with a given arrangement of magnets may be analyzed similarly to that of an array of charges. The analogy is not complete, however, since no isolated magnetic charges (magnetic monopoles) have been found in nature, though some scientists believe their existence possible.

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magnetic pole

magnetic pole, the two nearly opposite ends of the planet where the earth's magnetic intensity is the greatest, as the north and south magnetic poles. For the magnetic north, it is the direction from any point on the earth's surface linking the horizontal component of the magnetic lines of force with the observer and north magnetic pole; it is similar for magnetic south. The north magnetic pole, first located (1831) by British explorer Sir James C. Ross, is now about 78°N and 104°W in the Queen Elizabeth Islands of northern Canada. The south magnetic pole, reached (1909) by Australian geologists Sir T. W. E. David and Sir Douglas Mawson, is now about 66°S and 139°E on the Adélie Coast of Antarctica. The magnetic poles are not fixed but follow circular paths with diameters of about 100 miles (160 km). Studies of paleomagnetism also indicate that the earth's magnetic field has reversed its polarity many times in the geologic past. The best hypothesis to date for the origin of terrestrial magnetism is the self-exciting dynamo theory, where the earth's magnetic field is generated by the interaction of motion and electrical currents in the earth's liquid outer core.

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celestial pole

celestial pole, one of the two points at which the earth's axis of rotation intersects the celestial sphere. The celestial pole is important as a reference point in the equatorial coordinate system; the celestial meridian passes through it, as do the hour circles of the stars. The polestar (see Polaris) lies within 0.5° of the north celestial pole. Although there is no bright star near the south celestial pole, the Southern Cross (see Crux) points directly to it. The altitude of the celestial pole in an observer's hemisphere is equal to the observer's latitude on the earth.

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South Pole

South Pole, southern end of the earth's axis, lat. 90° S. It is distinguished from the south magnetic pole. The South Pole was reached by Roald Amundsen, a Norwegian explorer, in 1911. See Antarctica.

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Pole, William de la

Pole, William de la: see Pole, family.

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Pole, Richard de la

Pole, Richard de la: see Pole, family.

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Pole, Reginald

Pole, Reginald, 1500-1558, English churchman, archbishop of Canterbury (1556-58), cardinal of the Roman Catholic Church. He was a cousin of the Tudors, being the son of Sir Richard Pole and of Margaret, countess of Salisbury, who was the daughter of George, duke of Clarence, and the niece of kings Edward IV and Richard III. Although he did not take priestly orders until late in life, he was devout from the first and received many church benefices from Henry VIII. When his benefactor broke with the pope, Pole went abroad. In 1536 he made a formal statement of his views on the king's divorce, attacking the doctrine of royal supremacy. In the same year he accepted Pope Paul III's summons to sit on the commission to reform the pontifical administration and was created cardinal. In 1537 and again in 1538-39, Pole was active in trying to organize a league against Henry, who now was setting out to destroy the Pole family. However, Pole was unsuccessful in this endeavor, and he returned to Rome and received the legatine governorship of Viterbo. He was one of the legates appointed to open the Council of Trent (1545). In 1553, on Edward VI's death, Pope Julius III made him legate to England, and he and Mary I set about restoring the Roman Catholic Church. However, he ran afoul of Mary's husband, Philip II of Spain, and then of Pope Paul IV, and his difficulties were multiplied. He was always a mild man and would have nothing to do with the burning of heretics. In 1556 he was ordained priest and consecrated archbishop of Canterbury. He died the same day as Mary.

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Pole

Pole, English noble family. The first member of importance was William de la Pole, d. 1366, a rich merchant who became the first mayor of Hull (1332) and a baron of the exchequer (1339). His oldest son, Michael de la Pole, 1st earl of Suffolk, 1330?-1389, fought in France in the Hundred Years War under Edward the Black Prince. He became the trusted adviser of Richard II, who made him chancellor (1383) and earl of Suffolk (1385). In the Parliament of 1386 his enemies forced his dismissal, and he was impeached and imprisoned. Richard soon released and reinstated him, but when the baronial opposition again demanded his arrest, De la Pole fled (1387) to France. "Appealed" of treason and sentenced to death in the Merciless Parliament of 1388, he died in exile. His grandson, William de la Pole, 4th earl and 1st duke of Suffolk, 1396-1450, played an active role in the later stages of the Hundred Years War and for a time held the chief command. He arranged the marriage (1445) of Margaret of Anjou to Henry VI and rose to a position of great political authority, reaching the peak of his power in 1448 when he was made duke. His persistent efforts to gain peace with France enabled his enemies to accuse him of treason, especially after disastrous losses in Normandy. His long record of service, his eloquent appeal to Parliament, and even the favor of the king could not save him from impeachment. When setting out for a five-year exile he was abducted from his ship and beheaded in a boat off Dover. His wife was the granddaughter of Geoffrey Chaucer. His son, John de la Pole, 2d duke of Suffolk, 1443-91, married Edward IV's sister Elizabeth and held offices under that king. He later supported Richard III, yet was favored by Henry VII. Of his sons, the eldest was John de la Pole, earl of Lincoln, 1464-87, who was recognized by Richard III as his heir presumptive. At first he appeared to accept Henry VII, but he soon joined the rebellion in favor of Lambert Simnel. He led an invading army from Ireland and was killed at the battle of Stoke. The second son, Edmund de la Pole, earl of Suffolk, 1472?-1513, agreed to the wish of Henry VII that he forego the ducal title in return for some of the property forfeited as a result of his brother's treason. Later he declared his ambition for the throne and tried to get help on the Continent. He was eventually delivered (1506) as a prisoner to Henry VII by the Burgundians. He was imprisoned for years and finally executed by Henry VIII. The fifth son, Richard de la Pole, d. 1525, took over Edmund's claim to the throne and received intermittent support from the French. He was killed in the battle of Pavia fighting for Francis I of France. He was the last of his line.

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North Pole

North Pole, northern end of the earth's axis, lat. 90°N. It is distinguished from the north magnetic pole. U.S. explorer Robert E. Peary is traditionally credited as being the first to reach (1909) the North Pole. In 1926, Richard E. Byrd and Floyd Bennett may have been the first persons to fly over the pole, but entries in Byrd's diary suggest that they may have missed the actual pole; if so, that feat would belong to Roald Amundsen. See also Arctic, the.

See F. Fleming, Ninety Degrees North: The Quest for the North Pole (2002).

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Lincoln, John de la Pole, earl of

Lincoln, John de la Pole, earl of: see Pole, family.

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totem pole

Totem pole from Kitwancool Creek, B.C., Can.

Carved and painted vertical log, constructed by many Northwest Coast Indian peoples. The poles display mythological images, usually animal spirits, whose significance is their association with the lineage. Each figure represents a type of family crest. Some poles relate a family legend in the form of pictographs. Poles are erected to identify the owner of a house or other property, welcome visitors, indicate a portal or passageway, mark a gravesite, and even to ridicule an important person who failed in some way. Seealso symbol; totemism.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.

pole vault

Track-and-field event consisting of a vault for height over a crossbar with the aid of a long pole. It became a competitive sport in the mid-19th century and was included in the first modern Olympic Games. In competition, each vaulter is given three chances to clear a specific height. The bar is raised progressively until a winner emerges.

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bisj pole

Carved wooden pole used in the religious rites of the South Pacific islands. The poles, 12–26 ft (4–8 m) tall, resemble an upended canoe with an exaggerated prow; they consist of carved figures placed one atop the other (thought to represent deceased ancestors) and terminate in a flat projection of ornate, openwork ornament. They are intended to harbour the souls of the dead, keeping them away from the village, and are also used to transmit magical powers. Seealso totem pole.

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South Pole

Southern extremity of the Earth's axis, located at latitude 90° S. It is the southern point from which all meridians of longitude start. The area around it is a lofty plateau in west-central Antarctica, with ice as much as 8,850 ft (2,700 m) thick. It has six months of complete daylight and six months of total darkness each year. It was first reached by the Norwegian explorer Roald Amundsen in 1911, one month before the expedition led by British explorer Robert Falcon Scott; U.S. explorer Richard E. Byrd flew to the pole in 1929. The geographic pole does not coincide with the magnetic South Pole, which in the early 21st century was located on the Adélie Coast about 64°30' S, 137°50' E; it moves about 8 mi (13 km) to the northwest each year. The geomagnetic South Pole also moves; during the early 1990s it was located about 79°13' S, 108°44' E, in 2000 it was 65°39' S, 140° 01' E, and by 2005 it was back to about 79°45' S, 108°13' E.

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Pole, Reginald

(born March 3, 1500, Stourton Castle, Staffordshire, Eng.—died Nov. 17, 1558, London) English Catholic prelate. A cousin of Henry VII, Pole was sent by Henry VIII to study in Italy (1521–27) and given minor offices in the church. Critical of Henry's antipapal policies, he wrote In Defense of Ecclesiastical Unity (1536) to defend the pope's spiritual authority. As cardinal, he was sent by Pope Paul III on missions to persuade Catholic monarchs to depose Henry. These efforts angered Henry, who executed Pole's brother, Lord Montague (1538), and his mother, Margaret, countess of Salisbury (1541). Pole was named papal governor of the Patrimony of St. Peter and later was presiding legate at the Council of Trent. When the Catholic Mary Tudor became queen as Mary I in 1553, he was appointed legate for England; there he instituted church reforms and was a strong influence on the queen. He was appointed archbishop of Canterbury (1556), but a conflict between the papacy and England's ally Spain caused the pope to cancel Pole's authority and declare him a heretic. Demoralized, he died 12 hours after the death of Queen Mary.

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North Pole

Northern end of the Earth's geographic axis, located at latitude 90° N. It is the northern point from which all meridians of longitude start. Lying in the Arctic Ocean and covered with drifting pack ice, it has six months of constant sunlight and six months of total darkness each year. Robert E. Peary claimed to have reached the pole by dogsled in 1909, but that is now in dispute; Roald Amundsen and Richard E. Byrd claimed to have reached it by air in 1926. The geographic pole does not coincide with the magnetic North Pole, which in the early 21st century lay at about 82°45' N, 114°25' W, or with the geomagnetic North Pole, which is at about 79°45' N, 71°45' W.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.