sun worship. Deification and adoration of the sun occurred primarily in agrarian societies. When man became a farmer, and thus dependent upon daily and seasonal changes of weather, he often turned to worship the great force that regulated these changes—the light and heat of the sun. The worship of the sun, although not peculiar to any one time or place, received its greatest prominence in ancient Egypt. There, the daily birth, journey, and death of the sun was the dominating feature of life. One of the most important gods of Egyptian religion was Ra, the sun-god, who was considered the first king of Egypt. The pharaoh, said to be the son of Ra, was the sun-god's representative on earth. In later Egyptian religion, under the rule of Ikhnaton, the sun-god Aton gained complete supremacy in what was Egypt's only monotheistic period. In Mesopotamia, where sun worship was also very important, the sun-god Shamash was a major deity and was equated with justice. In Greece there were two sun deities, Apollo and Helios, although there was no institutionalized form of sun worship. The influence of the sun in religious belief also appears in Zoroastrianism, Mithraism, Roman religion, Hinduism, Buddhism, and among the Druids of England, the Aztecs of Mexico, the Incas of Peru, and many Native Americans.

sun grebe, common name for a tropical, mainly aquatic bird of the family Heliornithidae. Sun grebes, also called finfoots, are remarkable for their colorful, puffy-toed, webbed feet, which may serve as lures for fish and other aquatic animals. They are good divers and hunt, either swimming partially submerged or from low perches. Their diet consists mainly of small aquatic animals, but they are also known to eat some plant matter. They have elongate bodies, about 12 to 20 in. (30.5-51 cm) long, and necks with long and pointed, grebelike bills. However, they are not related to the true grebe. Shy and solitary creatures, sun grebes are found singly or in pairs, typically in the vicinity of densely wooded pools and streams, and little is known of their habits. Once widely distributed, they are now limited to three species. The largest of these is the Asian sun grebe (Heliopais personata) measuring up to 20 in. (51 cm) in length, and found from Bengal to Malaya and Sumatra. Its body is olive-brown above, with a black head and throat, a yellow bill, and bright green legs with white stripes. At 16 in. (41 cm), the African finfoot (Podica senegalis) is dark brown with black and white spots above, a white belly, and bright red feet and legs. It is thought to be more of a climber than the other species. Only a third to a quarter as bulky as the Asian sun grebe and measuring less than 12 in. (30 cm) in length is the American sun grebe (Heliornis fulica) of South and Central America. Its plumage is colored similarly to that of the Asian sun grebe, but it is scarlet-billed with yellow, black-striped legs. All three species are marked by a white band running from eye to neck. Sun grebes build their nests from grass and reed, on platforms away from water. The female lays from two to five white, red-and-buff streaked eggs per clutch. Sun grebes are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Gruiformes, family Heliornithidae.

sun god: see sun worship.

sun dance, ceremony typical of the Plains Indians of North America. The ceremony was performed in the summer and lasted from two to eight days. Some of the ceremony was secret. Smoking, fasting, and other rites were part of the ceremony. Penance through self-torture was practiced to achieve communion with the forces of the universe. Among some Native Americans, a bison skull was pulled around the lodge by means of a thong and peg inserted through the skin of the participant's chest. Missionaries and the U.S. and Canadian governments prohibited the ceremony.

sun, intensely hot, self-luminous body of gases at the center of the solar system. Its gravitational attraction maintains the planets, comets, and other bodies of the solar system in their orbits.

General Characteristics of the Sun

The sun is actually a star of about medium size; it appears larger than the other stars because of its relative nearness to the earth. The earth's distance from the sun varies from 91,377,000 mi (147,053,000 km) at perihelion to 94,537,000 mi (152,138,000 km) at aphelion (see apsis). The mean distance is c.92,960,000 mi (149,591,000 km); this is taken as the astronomical unit (AU) of distance used for measuring distances within the solar system. The sun is approximately 865,400 mi (1,392,000 km) in diameter, and its volume is about 1,300,000 times that of the earth. Its mass is almost 700 times the total mass of all the bodies in the solar system and 332,000 times that of the earth. The sun's surface gravity is almost 28 times that of the earth; i.e., a body on the surface of the sun would weigh about 28 times its weight on earth. The density of the material composing the sun is about one fourth that of the earth; compared with water, the sun's average density is 1.41. At its center, the sun has a density of over 100 times that of water, a temperature of 10 to 20 million degrees Celsius, and a pressure of over 1 billion atmospheres.

Observations of sunspots and studies of the solar spectrum indicate that the sun rotates on its axis from east to west; because of its gaseous nature its rate of rotation varies somewhat with latitude, the speed being greatest (a period of almost 25 days) in the equatorial region and least at the poles (a period of about 35 days). The axis of the sun is inclined at an angle of about 7° to the plane of the ecliptic.

The bright surface of the sun is called the photosphere. Its temperature is about 6,000°C;. The photosphere appears darker near the edge (limb) of the sun's disk because of greater absorption of light by the sun's atmosphere in this area; this phenomenon is called limb darkening. During an eclipse of the sun the chromosphere and the corona (the outer layers of the sun's atmosphere) are observed. Also of interest is the high-speed, tenuous extension of the corona known as the solar wind.

Production of Solar Energy

The vast and continual production of solar energy cannot be attributed merely to combustion, to the gradual cooling of a hot body, to the fall of meteorites into the sun, or to gradual shrinkage with transformation of potential energy into heat (a theory proposed by Helmholtz). The theory of relativity with its implication of the equivalence of mass and energy led to the assumption that energy stored in the atoms constituting the sun's gases is constantly being released by conversion of some of the masses of the atom's nuclei during nuclear transmutations (see nuclear energy). H. A. Bethe proposed a cycle of nuclear reactions known as the carbon cycle, or CNO bi-cycle, to account for the nuclear changes. In this cycle carbon acts much as a catalyst, while hydrogen is transformed by a series of reactions into helium and large amounts of high-energy gamma radiation are released. It is now thought that the so-called proton-proton process is a more important energy source; this process begins with the collision of two protons and ends with the production of helium, while gamma radiation is released throughout.

See nucleosynthesis; stellar evolution.

The Study of the Sun

By means of the spectroscope much has been learned about the composition of the sun. There are numerous dark lines of varying widths in the solar spectrum. These were first intensively studied by Joseph Fraunhofer and are commonly known by his name. From a study of the lines the chemical composition of the sun is determined on the basis of the discovery by Kirchhoff that the dark lines correspond in position to the bright lines characteristic of the spectra produced by elements in the laboratory. The darkness of the lines in the sun's spectrum is attributed to the presence of a slightly cooler layer of gases above the photosphere, known as the reversing layer, which absorbs selectively the light of the photosphere and thus causes dark lines instead of bright ones to be observed through the spectroscope. By comparison of the sun's spectrum with laboratory spectra of incandescent elements, most of the elements known on earth have been identified in the sun's atmosphere.

Beyond the red portion of the visible solar spectrum is the infrared spectrum; for the study of these heat rays S. P. Langley invented the bolometer, a highly sensitive electrical device for measuring temperature. Solar heat and energy are measured by an instrument called the pyrheliometer. Other instruments devised especially for the study of the sun are the coronagraph and the spectroheliograph. These instruments have revealed a number of interesting phenomena occurring during the periods of solar activity associated with sunspots, e.g., faculae, plages (flocculi), prominences, and flares.

Importance to Terrestrial Life

Without the heat and light of the sun, life as we know it could not exist on the earth. Since solar energy is used by green plants in the process of photosynthesis, the sun is the ultimate source of the energy stored both in food and fossil fuels. Solar heating sets up convection currents, and thus is the source of the energy of moving air. Falling rain also owes its energy to the sun because of the relation of solar radiation to the water cycle.

midnight sun, phenomenon in which the sun remains visible in the sky continuously for 24 hr or longer, occurring only in the polar regions. The midnight sun is due to the fact that the plane of the earth's equator is tilted about 231/2° to the plane of the ecliptic (the apparent path of the sun through the sky). Thus, at the summer solstice (about June 22), the sun is still visible on the horizon at midnight at all points along the Arctic Circle, 231/2° of latitude from the North Pole. At points north of the Arctic Circle, the midnight sun is visible for longer than one day, the North Pole having a full six months of continuous sun from the vernal equinox (about Mar. 21) to the autumnal equinox (about Sept. 23). In the south polar regions the midnight sun is visible along the Antarctic Circle at the winter solstice (about Dec. 22) and south of the Antarctic Circle for longer periods.

Sun Yat-sen, Mandarin Sun Wen, 1866-1925, Chinese revolutionary. He was born near Guangzhou into a farm-owning family. He attended (1879-82) an Anglican boys school in Honolulu, where he came under Western influence, particularly that of Christianity. In 1892 he received a diploma from a Hong Kong medical school, and he subsequently practiced medicine in that city. Thereafter all his activities were devoted to overthrowing the Ch'ing dynasty and establishing a stable Chinese republic.

Sun fled China in 1895, after an abortive revolt, and then toured the world several times to enlist the aid of overseas Chinese in financing his activities. In that period he made an intensive study of Western political and social theory and was deeply impressed with the writings of Karl Marx and Henry George. Sun organized (1905) a revolutionary league, the T'ung Meng Hui, in Japan and gradually perfected his political conceptions, which were based on the Three People's Principles: nationalism, democracy, and the people's livelihood. Revolution erupted in China, and Sun was elected provisional president of the Chinese republic in Dec., 1911, but two months later he resigned in favor of Yüan Shih-kai. Later, when Sung Chiao-jen transformed the T'ung Meng Hui into a federated political party called the Kuomintang, Sun served as its director.

Meanwhile, opposition developed to Yüan's dictatorial methods; in 1913 Sun led an unsuccessful revolt against Yüan, and he was forced to seek asylum in Japan, where he reorganized the Kuomintang. He returned to China in 1917, and in 1921 he was elected president of a self-proclaimed national government at Guangzhou in S China. To develop the military power needed for the Northern Expedition against the militarists at Beijing, he established the Whampoa Military Academy (now Huangpu Military Academy), with Chiang Kai-shek as its commandant and with such party leaders as Wang Ching-wei and Hu Han-min as political instructors. In 1924, to hasten the conquest of China, he began a policy of active cooperation with the Chinese Communists and he accepted the help of the USSR in reorganizing the Kuomintang.

After Sun's death, when the Communists and the Kuomintang split (1927), each group claimed to be his true heirs. The official veneration of Sun's memory (especially in the Kuomintang) was a virtual cult, which centered around his tomb in Nanjing. His widow, the former Soong Ch'ing-ling (see Soong, family), whom he married in 1914, rose to a high position in the government of Communist China. He wrote San Min Chu I (tr. 1928), Memoirs of a Chinese Revolutionary (1927, repr. 1970), and Fundamentals of National Reconstruction (tr. 1953).

Sun Valley, mountain resort city (1990 pop. 938), alt. c.6,000 ft (1,830 m), Blaine co., S central Idaho; inc. 1967. It is a popular year-round resort with both winter and summer sports. It was founded as a ski resort in 1936 by W. Averell Harriman, then board chairman of the Union Pacific RR; the railroad purchased the land and built the resort to attract more passenger traffic to the West. In 1964 it was sold to a land-development corporation; in 1967, Bill Janss, a former Olympic skier, became sole owner. The Hemingway Memorial, on a bluff overlooking a swift-flowing trout stream, was dedicated in 1966.

Sun Tzu, fl. c.500-320. B.C., name used by the unknown Chinese authors of the sophisticated treatise on philosophy, logistics, espionage, and strategy and tactics known as The Art of War. It includes many commentaries by later Chinese philosophers. The core text was probably written by one person during a time of expanding feudal conflicts, but the exact century is uncertain. Most authorities now support a date early in the Warring States period (c.453-221 B.C.). This work has deeply influenced Chinese, Vietnamese, and Japanese military thinking and has enjoyed growing popularity among businessmen. It stresses the unpredictability of battle, the importance of deception and surprise, the close relationship between politics and military policy, and the high costs of war. The futility of seeking hard and fast rules and the subtle paradoxes of success are major themes. The best battle, Sun Tzu says, is the battle that is won without being fought. See guerrilla warfare.

Sun Belt or Sunbelt, southern tier of the United States, focused on Florida, Texas, Arizona, and California, and extending as far north as Virginia. The term gained wide use in the 1970s, when the economic and political impact of the nation's overall shift in population to the south and west became conspicuous. Areas near the Mexican border have received millions of immigrants since the 1960s. Economic growth in many Sun Belt cities since World War II has stimulated interregional migration from the NE United States and the Rust Belt; by 1990, Los Angeles, San Diego, Phoenix, Houston, Dallas, and San Antonio were among the ten largest cities in the United States. During the 1990s the fastest growing cities in the United States were in the Sun Belt. The warm climate has attracted large retirement communities, especially in Florida and Arizona. In addition, the birth rate in the Sun Belt is about 10% greater than that in the rest of the country. Attracted by the relative lack of labor unions and the prospect of cheaper labor than was generally available in the north, manufacturers began to locate in the Southeast in significant numbers after World War II; aerospace firms and defense contractors were drawn to the vicinity of military bases in S California and throughout the Southwest. Texas, Louisiana, and Oklahoma benefited from the oil booms of the 1970s. In addition, the enormous tourist industries of the Sun Belt (especially Florida and S California) have brought the region considerable wealth. Although overall the expansion of the Sun Belt's economy in recent decades has been dramatic, the distribution of the region's prosperity has been uneven; of the 25 metropolitan areas with the lowest per capita income in 1990, 23 were in the Sun Belt. The rapid fall of oil prices in the 1980s hurt the economies of the energy-producing areas of the Sun Belt; Houston was especially hard hit. By the 1980s, the Los Angeles area, beset by problems ranging from air pollution to a growing population of unskilled immigrants, came increasingly to resemble some of the troubled metropolitan areas of the North. Politically, the rise of the Sun Belt has generally been viewed as advantageous to the Republican party, especially in presidential elections. Since 1970, the Sun Belt has gained more than 25 electoral votes, mostly at the expense of the Northeast and Midwest.

Sun, river, c.130 mi (210 km) long, rising in the Rocky Mts., NW Mont., and flowing generally E to the Missouri River at Great Falls. The Sun River project of the U.S. Bureau of Reclamation utilizes the Sun and its tributaries to irrigate c.92,000 acres (37,230 hectares) of land. Of the system of dams and reservoirs, Gibson Dam is one of the project's largest.

Moon, Sun Myung, 1920-, Korean religious leader. He was an engineering student and dock worker before founding (1954) the Unification Church with a doctrine loosely based on Christianity as interpreted by Moon, who has declared (2004) himself the "Messiah." Moon introduced the movement to the United States in the 1960s; its world headquarters are now in New York City. Moon has been accused of brainwashing converts and of various illegal activities; he was convicted (1982) of conspiracy to evade taxes.

Veneration of the sun or its representation as a deity. It appears in several early cultures, notably in ancient Egypt, Indo-Europe, and Mesoamerica, where urban civilizations were combined with a strong ideology of sacred kingship, in which kings ruled by the power of the sun and claimed descent from it. The imagery of the sun as the ruler of both the upper and the lower world, which he visits daily, was prominent. Sun heroes and deities also figure in many mythologies, including Indo-Iranian, Greco-Roman, and Scandinavian. In late Roman history, sun worship was of such importance that it was later called “solar monotheism.” Seealso Amaterasu, Re, Shamash, Sol, Surya, Tonatiuh.

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Most important religious ritual of the Plains Indians of North America. Ordinarily held by each tribe once a year in early summer, it is simultaneously an opportunity to reaffirm basic beliefs about the universe and the supernatural through rituals and a highly sacred event through which personal sacrifice is undertaken for the general well-being of the community and the individual. The ritual originated long ago and has been widely adopted by indigenous Plains peoples from Saskatchewan, Can., to Texas, U.S. The central rite involves male supplicants who, in order to fulfill a vow, to seek spiritual energy and insight, and for the health of the community, pledge to dance for several days without stopping for food, drink, or sleep, their ordeal ending in exhaustion. Among some tribes, piercing and sun gazing are practiced.

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or honey bear

Smallest member (Helarctos malayanus) of the bear family (Ursidae), found in South Asian forests. Nocturnal and tree-climbing, the sun bear weighs 60–140 lbs (27–64 kg) and is 3–4 ft (1–1.2 m) long, with a 2-in. (5-cm) tail, large forepaws, and short black fur with an orange-yellow crescent on the chest. It uses its long, curved claws to tear or dig for insect nests, particularly those of bees and termites. It also eats fruit, honey, and small vertebrates. The sun bear is shy and intelligent; legends say that its chest crescent represents the sun.

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or Sun Yixian

(born Nov. 12, 1866, Xiangshan, Guangdong province, China—died March 12, 1925, Beijing) Leader of the Chinese Nationalist Party, known as the father of modern China. Educated in Hawaii and Hong Kong, Sun embarked on a medical career in 1892, but, troubled by the conservative Qing dynasty's inability to keep China from suffering repeated humiliations at the hands of more advanced countries, he forsook medicine two years later for politics. A letter to Li Hongzhang in which Sun detailed ways that China could gain strength made no headway, and he went abroad to try organizing expatriate Chinese. He spent time in Hawaii, England, Canada, and Japan and in 1905 became head of a revolutionary coalition, the Tongmenghui (“Alliance Society”). The revolts he helped plot during this period failed, but in 1911 a rebellion in Wuhan unexpectedly succeeded in overthrowing the provincial government. Other provincial secessions followed, and Sun returned to be elected provisional president of a new government. The emperor abdicated in 1912, and Sun turned over the government to Yuan Shikai. The two men split in 1913, and Sun became head of a separatist regime in the south. In 1924, aided by Soviet advisers, he reorganized his Nationalist Party, admitted three communists to its central executive committee, and approved the establishment of a military academy, to be headed by Chiang Kai-shek. He also delivered lectures on his doctrine, the Three Principles of the People (nationalism, democracy, and people's livelihood), but died the following year without having had the opportunity to put his doctrine into practice. Seealso Wang Jingwei.

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Star around which the components of the solar system revolve. It is about five billion years old and is the dominant body of the system, with more than 99percnt of its mass. It converts five million tons of matter into energy every second by nuclear fusion reactions in its core, producing neutrinos (see solar neutrino problem) and solar radiation. The small amount of this energy that penetrates Earth’s atmosphere provides the light and heat that support life. A sphere of luminous gas 864,950 mi (1,392,000 km) in diameter, the Sun has about 330,000 times the mass of Earth. Its core temperature is close to 27 million °F (15 million °C) and its surface temperature about 10,000 °F (6,000 °C). The Sun, a spectral type G (yellow) star, has fairly average properties for a main-sequence star (see Hertzsprung-Russell diagram). It rotates at different rates at different latitudes; one rotation takes 36 days at the poles but only 25 days at the equator. The visible surface, or photosphere, is in constant motion, with the number and position of sunspots changing in a regular solar cycle. External phenomena include magnetic activity extending into the chromosphere and corona, solar flares, solar prominences, and the solar wind. Effects on Earth include auroras and disruption of radio communications and power-transmission lines. Despite its activity, the Sun appears to have remained relatively unchanged for billions of years. Seealso eclipse; heliopause.

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(born Jan. 6, 1920, Kwangju Sangsa Ri, P'yŏngan-puk province, Korea) South Korean religious leader. Convinced that he was designated by God as a successor to Jesus, Moon began to preach a new religion, loosely based on Christianity, in North Korea in 1946. After being imprisoned by North Korean authorities, he escaped or was released and went to South Korea, where he founded the Unification Church in 1954 and built a multimillion-dollar business empire. In 1973 he moved his headquarters to Tarrytown, N.Y., U.S., where he became the focus of controversies over fund-raising techniques, tax evasion, and the indoctrination of followers (popularly called Moonies). In 1982 Moon was convicted of tax evasion, sentenced to 18 months in prison, and fined $25,000. He has also suffered from a damaging exposé by his daughter-in-law. In the 1990s the church began operations in Brazil, where its purchase of large tracts of rainforest has been widely criticized.

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