Cambodia, and Central Asia. Islam spread from its original Arabian home to become important in the Middle East, South Asia, Central Asia, and elsewhere. Members of the earlier human species Homo erectus migrated from Africa to East Asia at least one million years ago. One of the ear¬ liest civilizations to use writing developed in the Tigris and Euphrates river valleys c. 3000 bc (see Mesopotamia). Civilization in the Indus River valley and in northern Syria followed c. mid-3rd millennium bc. Chinese urban civilization began with the Shang dynasty (c. 1600-1046 bc) and continued under the Zhou dynasty (1046-256 bc). Indo-European¬ speaking peoples (Aryans) began to invade India from the west c. 2000- 1500 bc and developed the Vedic religion. A succession of empires and charismatic rulers, including the Macedonian Alexander the Great, spread their political control as far as military power could carry them. In the 13th century ad Genghis Khan and his Mongol successors united much of Asia under their rule. In the 14th century the Turkic warlord Timur con¬ quered much of Central Asia. Muslim Turks destroyed the remnants of the Byzantine Empire in the 15th century. In the 19th century European imperialism began to replace Asian imperialism. Tsarist Russia pushed its political control across Asia to the Pacific Ocean, the British gained con¬ trol of India and Burma (Myanmar), the French dominated eastern South¬ east Asia (see French Indochina), the Dutch occupied the East Indies (Indonesia), and the Spanish and later the U.S. ruled the Philippines. After World War II (1939-45), European imperialism steadily disappeared as former colonies gained independence in the second half of the 20th cen¬ tury. See map on opposite page.
Asia Minor See Anatolia
Asimov Va-zi-.moA, Isaac (b. Jan. 2, 1920, Petrovichi, Russia—d. April 6, 1992, New York, N.Y., U.S.) Russian-born U.S. author and bio¬ chemist. He arrived in the U.S. at age 3, earned a doctorate from Colum¬ bia University, and subsequently taught for many years at Boston University. Before embarking on graduate study, he had already begun publishing his stories. “Nightfall” (1941) is often called the finest science- fiction short story ever written. His I, Robot (1950) greatly influenced how later writers treated intelligent machines. A trilogy of novels— Foundation, Foundation and Empire, and Second Foundation (1951— 53)—is widely considered a classic. Asimov’s nonfiction science books for lay readers are noted for their lucidity and humour. Immensely pro¬ lific, he published more than 300 volumes in all.
Askja \'as-kya\ Caldera, Iceland. The largest crater in the Dyngjufjbl volcanic massif, Askja lies 20 mi (32 km) north of Vatnajokull, Iceland’s largest ice field. Its rugged peaks, up to 4,954 ft (1,510 m), encircle a lake of 4.25 sq mi (11 sq km) that occupies the caldera. The volcano erupted in 1875 and again in 1961.
Asmara Vas-ma-ra\ City (pop., 2002 est.: 500,600), capital of Eritrea. It lies on the northern tip of the Ethiopian Plateau at an elevation of 7,628 ft (2,325 m). Its Red Sea port, Massawa, is 40 mi (65 km) northeast. For¬ merly a hamlet of the Tigre people, Asmara became the capital of the Ital¬ ian colony of Eritrea in 1900. It was under British control from 1941 until Eritrea’s federation with Ethiopia in 1952 and became the capital of inde¬ pendent Eritrea in 1993. It is an agricultural marketplace.
Aso \'a-so. Mount Japanese Aso-san Volcanic mountain, central Kyushu island, Japan. The highest of its five peaks is about 5,223 ft (1,592 m) tall. It has one of the largest active craters in the world, measuring 71 mi (114 km) in circumference; its caldera marks the original crater and contains an active volcano and hot springs. The crater is inhabited; its pastures are used for cattle raising and dairy farming. The volcano is at the centre of Aso-Kuju National Park.
Asoka See Ashoka
asp Anglicized form of aspis, the name used in classical antiquity for a venomous snake, probably the Egyptian cobra (Naja haje ). The asp was the symbol of royalty in Egypt, and its bite was used for the execution of criminals in Greco-Roman times. Cleopatra is said to have killed herself with an asp.
asparagine \3-'spar-3-jen\ One of the nonessential amino acids, widely distributed in plant proteins and closely related to aspartic acid. First iso¬ lated in 1806 from asparagus, it is used in medicine and biochemical research.
asparagus Any plant of the genus Asparagus (lily family), which con¬ tains about 300 species native from Siberia to southern Africa. The best-
© 2006 Encyclopaedia Britannica, Inc.
© 2006 Encyclopaedia Britannica, Inc.
117
118 I aspartame ► Assam
known and economically most important species is the garden asparagus (A. officinalis ), cultivated as a green vegetable for its succulent spring stalks. Several African species are grown as ornamental plants. The poi¬ sonous species prized for their delicate and graceful foliage are A. plu- mosus (the feathery asparagus fern, or florists’ fern—not a true fern), A. sprengeri, and A. asparagoides.
aspartame Vas-por-.tamX Synthetic organic compound (a dipeptide) of phenylalanine and aspartic acid. It is 150-200 times as sweet as cane sugar and is used as a nonnutritive tabletop sweetener and in low-calorie pre¬ pared foods (brand names NutraSweet, Equal) but is not suitable for bak¬ ing. Because of its phenylalanine content, persons with phenylketonuria must avoid it. Though it is approved by the U.S. Food and Drug Admin¬ istration and other regulatory authorities around the world, its safety even for those without the disease remains controversial. See also saccharin.
aspartic acid One of the nonessential amino acids, found in many pro¬ teins and closely related to asparagine. It is used in medical and biochemi¬ cal research, as an organic intermediate, and in various industrial applications. It is one of the two components of aspartame.
Aspasia Vas-'pa-shoX (fl. 5th century bc) Mistress of Pericles and a vivid figure in Athenian society. Originally from Miletus, she lived with Peri¬ cles from c. 445 bc until his death in 429. Because she was not a citizen, their son was initially denied civic rights. Though an intellectual admired by Socrates, she endured public attacks, especially in comic theatre, for her private life and her supposed influence on Pericles’ foreign policy.
Aspen City (pop., 2000: 5,914), western central Colorado, U.S. It is located on the Roaring Fork River at the edge of the White River National Forest, at an altitude of 7,907 ft (2,410 m). Founded by prospectors c. 1878, it was a booming silver-mining town by 1887 but declined rapidly after silver prices collapsed in the early 1890s. Its revival as a ski resort began in the late 1930s, and it is now a popular tourist town; it is also known for its cultural festivals, notably the Aspen Music Festival.
aspen Any of three tree species of the genus Populus, of the willow family: P. tremula (the common European aspen), P. tremuloides (the American quaking, or trembling, aspen), and P. grandidentata (the Ameri¬ can big-tooth aspen). Native to the Northern Hemisphere, aspens are known for the fluttering of their leaves in the slightest breeze. Aspens grow farther north and higher up the mountains than other Populus spe¬ cies. All aspens have a smooth, gray-green bark, random branching, rich green leaves that turn brilliant yellow in fall, and catkins that appear before the leaves in spring.