Most of the advances in the scientifi c study of the heavens in ancient eastern Asia were achieved by the people of China, where astronomical truths were sought largely to refi ne the
understanding of astrology. Kings, in fact, restricted such study to scholars under royal employment, in hopes of main- taining a sure hold on power that was oft en secured through accurate predictions. Into medieval times ordinary citizens were punished for possessing or using objects associated with the measurement of celestial bodies or with divination based on such measurements. Th e importance ascribed to the study of astronomy is refl ected in the fact that the Chinese record- ed a number of observations before either the Greeks or the Babylonians.
In general, the ancient Chinese classifi ed astronomical events into two categories: predictable and unpredictable. Predictable events included the shift ing of the phases of the moon and the rotation of the constellations around the North Star. Unpredictable events of particular note included the wandering of the planets (whose orbits were long undeter- mined in geometric terms), the appearance of comets, and instances of sunspots, which were especially observable when dust storms in northern China screened the sun’s glare. A great deal of attention was paid to these unpredictable events, which wise men, particularly those in the service of rulers, interpreted in order to extract cosmic meaning.
Knowledge regarding predictable events, then, was val- ued largely for its providing the frame of reference against which unpredictable events occurred. Th e origins of an impe- rial almanac, which served as a register of these predictable events, are so ancient as to be obscure. Th e almanac delin- eated the annual astronomical cycle, including the lengths of the months (which were based on the phases of the moon and thus varied from year to year) and the dates of the equi- noxes (the two times of the year at which the sun crosses the equator and day and night are of relatively equal length) and solstices (the times of year when the sun is at the greatest dis- tance from the equator and the day is either at its shortest or at its longest, depending on the season). Th e year began at the winter solstice, when the yang force—a Chinese concep- tion associated with warmth, among other qualities—was at its nadir. Since the winter solstice oft en proved to be a cloudy day, its date was calculated based on that of the summer sol- stice, which was determined through the measurement of the shadow of an 8-foot stone pillar. Th e length of the year was estimated to be 366 days until the fourth century b.c.e., when the fi gure was revised to 365¼ days; further corrections were made continually thereaft er.
According to legend, basic star charts were fi rst compiled sometime before 1000 b.c.e. by a shaman named Xian, who identifi ed the Big Dipper, among other constellations. Th e revolution and rotation of the Big Dipper around the North Star, rather than the movement of the sun, provided the ba- sis for many Chinese astronomical computations. Records still exist of the star charts compiled in the fourth century b.c.e. by the early astronomical observers Shi Shen and Gan De—whereas charts compiled by Timocharis (ca. 320– 260 b.c.e.), of Greece, have never been found. Much later, in the fi ft h century c.e., Qian Lezhi incorporated the fi ndings of his
Covered jar, from the second to fi rst century b.c.e., China; the scene is of a blue beast (the star Sirius) with bared fangs lunging at a mounted archer (the adjoining constellation, Bow). (Copyright the Metropolitan Museum of Art)
128 astronomy: Asia and the Pacific
three regional predecessors into a single chart, coding their fi ndings with the colors white, red, and black.
Comets, eclipses, and supernovae (explosions of stars) were seen as especially momentous astronomical occurrenc- es. Records of comets are more extensive in China than in anywhere else in the ancient world, and these records pro- vided the original basis for determining the orbit of Halley’s comet, which was sighted in China fi rst, in 240 b.c.e. Records of eclipses extend back even further in time, as inscriptions were found on oracle bones— animal bones that were used for divination—dating back to the Shang Dynasty, which ended around 1045 b.c.e. Th us, Chinese records predate Babylonian ones by some seven centuries. Starting in the third century b.c.e. eclipses were carefully registered. Supernovae, which are stellar explosions that can make distant stars visible to the naked eye for the fi rst time, were referred to as inexplicable
new stars or stranger stars.
Th e Chinese made a number of advances in the design of astronomical equipment. Th e Han Dynasty, which lasted from the second century b.c.e. to the second century c.e., witnessed the invention of a star-mapping tool called the ar-
millary sphere, a fi xed set of rings demarcating the sectors of
equator, dubbed the Gauge of the Red Road, was particularly important, as it allowed for increased accuracy in the mea- surement of the paths of the sun and moon; the astronomer Geng Shouchang, who lived during the fi rst century b.c.e., is credited with the invention of the equatorial ring. In the fi rst century c.e. an even more important ring was added: one de- noting the ecliptic, or the path taken by the earth around the sun, allowing for even greater accuracy in measurement tak- ing and prediction making, especially with regard to eclipses; this ring was dubbed the Gauge of the Yellow Road. Overall, Chinese astronomical predictions never equaled those of the Greeks, whose geometry was more refi ned.
One of the most renowned Chinese astronomers was Zhang Heng, who lived in the second century c.e. and was also a poet. He is widely credited with the invention of the fi rst comprehensively functional armillary sphere, featuring rings representing the equator and the ecliptic as well as a meridian, circling the earth over the poles, and a horizon. Th e accuracy of this sphere, which was a yard in diameter and was dubbed the Gauge of the Enveloping Sky, allowed a fourth- century astronomer named Yu Xi to discover the fact that the equinoxes occurred some 20 minutes earlier every year, a process called the precession of the equinoxes. (Th is process was actually fi rst discovered by the Greek Hipparchus around 120 b.c.e.) Zhang Heng is also presumed to have built the fi rst orrery, a smaller armillary sphere combined with representa- tions of other bodies in the solar system, all of which moved in accordance with reality using water power. Th is smaller sphere was a prototype for modern clockwork.
Advances in astronomy were also achieved in ancient India, though on a less defi nitive scale. One known fact is that during the rule of the Guptas, in the fourth and fi ft h centuries c.e., the number of days in the year was calculated with accuracy exceeding that attained by the Greeks. Other- wise, generally speaking, scientifi c knowledge was recorded in such elaborate Sanskrit that the sharing—and further de- veloping—of that knowledge was somewhat hindered. Other Asian and Pacifi c cultures, including those in Japan, Korea, Southeast Asia, and Australia, are known to have amassed knowledge of the stars, particularly of the appearances of constellations, over the millennia. However, little concrete evidence exists to demonstrate how far back into ancient times this knowledge existed.