Popular Science Monthly/Volume 55/July 1899/Origin of Ancient Hindu Astronomy



IT is manifest that India is indebted for some of its astronomy to the Greeks. Not that it had not astronomy and astronomers from an epoch anterior to the invasion of Alexander. It had, in fact, been necessary to make observations of the heavens in order to fix a calendar that would enable the sacrifices of the Vedic ritual in connection with the return of the seasons and the revolutions of the stars to be celebrated at the right dates. Further, the belief in astrology, or the influence exercised by the movements of the planets on physical phenomena and all the events of human life, would lead, in India as elsewhere, to the observation and anticipation of everything relating to the conjunction and opposition of the heavenly bodies.

The Rig-Veda has allusions to the phases and stations of the moon. The stations (nakshatras) consisted, according to a tradition preserved by the Brahmans, of twenty-seven constellations (afterward twenty-eight) which the moon was supposed to traverse successively in the course of its sidereal revolution. A lunar zodiac and a primary division of time into months were thus obtained. The moon, moreover, bears in the Veda the name of month-maker (mâsakrit). Each station was assigned a uniform length of 13° 20' on the ecliptic, and a denomination, generally derived from mythology. The month, in turn, took its name from the constellation that had the honor of harboring the moon. Manon and the Djyotisha (a special treatise included among the Védângas, or commentaries on the Vedas) tell us that the year was composed of twelve months, the month of thirty days, the day of thirty hours, the hour of forty-eight minutes, all strictly sexagesimal subdivisions, like our own measures of time. The Djyotisha also teaches the art of constructing a clepsydra, or water-clock.

The adjustment of the solar year to correspond with the lunar year and of the two with the civil year dates from this period. The month was still composed of thirty days, but the solar years were grouped into quinquennial periods, in the middle and at the end of which the lunar month was doubled. Combining these quinquennial periods with the revolutions of the planet Brihaspati (Jupiter), which was calculated as occupying about twelve years, the Indian astronomers computed an astronomical cycle of sixty solar years. As the same cycle is found with the Chaldeans, where, according to Berosus, it was called the Sossos, we have to inquire how far Brahmanic astronomy was influenced by the systems which were originally formed in ancient Chaldea. The presumption of such an influence furnishes a simpler and more probable hypothesis than the effort to trace the earliest astronomical ideas of the Hindus, as M. W. Brennand has recently suggested, to a period when the ancestors of the Aryans, the Semites, and the Chinese were wandering together over the plateaus of central Asia!

We know now, from the cuneiform inscriptions, that the Chaldeans had, at a period far anterior to the entrance of the Aryans into India, invented a double calendar, solar and lunar, with intercalary periods; discovered the proper motion of the planets; calculated the return of eclipses; and constituted a double metrical system, decimal and sexagesimal; and, as was done, too, in India, had divided the circumference into three hundred and sixty degrees of sixty minutes each. It is impossible to draw the lines exactly between the astronomical discoveries which the Hindus borrowed from abroad and those which they drew from their own resources prior to the invasion of the Greeks, but we need in no case go farther than Mesopotamia for the source of the borrowed data.

The ancient literature of India contains observations of the positions or conjunctions of some of the stars that carry us back to positive dates in the history of the sky. The astronomers Bailly, Colebrooke, and Bentley, and, more recently, M. Brennand, have found notes relative to astronomical phenomena that took place in the twelfth, fourteenth, fifteenth, and even the twenty-first centuries B.C. Max Müller, however, advises prudence and reserve in accepting these calculations, some of which may have been afterthoughts, and others offer only apparent agreements.

In any case, the advent of Buddhism, by depreciating the religious practices and astrological speculations of the Brahmans, contributed to bringing on a decline of astronomy at the very time it was taking its most vigorous stand among the Greeks. We learn from a passage in Strabo that the Pramnai regarded the Brahmans as boasters and mad because they were interested in physiology and astronomy. Now, there really exists an ancient Buddhist treatise in which the predictions by the Brahmans of eclipses of the sun and of the conjunctions and oppositions of the planets, and their discussions of the appearance of comets and meteors, are treated as despicable arts and lies.

It was just at this age that Hellenic culture was developed in northwest India. It held astronomy, and astrology too, in great esteem. The Milinda Panda mentions the royal astrologer as one of the principal functionaries of Menander. No doubt there were, among the Gavanas (Ionians) of Taxila and Euthydêmia, minds versed in the knowledge of the principal cosmological systems formulated among the Greeks from Thales to Aristotle, and also acquainted with all the progress in the physical and mathematical sciences that had been achieved by the Alexandrian astronomers in the last centuries before Christ. To comprehend the extent of the influence of Hellenic science, we have only to inquire what Hindu astronomy had bcome again at the time of the restoration of the Brahmans in the sixth century A.D. Aryabhatta teaches the rotation of the earth around its axis; maintains that the moon, naturally dark, owes its light to the rays of the sun; formulates the true theory of eclipses; assigns an elliptical form to the planetary epicycles; and demonstrates the displacement of the equinoctial and solstitial points. Varaha-Mihira devotes himself especially to astrological labors, but also has the merit of having condensed into a vast encyclopædia the Pantcha Siddhântikâ, the principal astronomical treatises that were current in India. And Brahmazoupta is especially famous for his revision of an older treatise, the Brahma Siddhânta.

In the opinion of the most competent critics, these works, which are chiefly empirical methods of determining the positions of the stars, are inferior to those which the Alexandrians have left us. Yet, in matters relating to the measurement of arcs and to spherical trigonometry, they reveal a more advanced state of the science. It is impossible to determine at what period this new astronomical science was constituted in India. Some of its theories squarely betray their indebtedness to Greek science, as, for instance, that of the displacement of the equinoctial and solstitial points by a periodical vibration or tremor. We can also say as much of the solar zodiac, the names of the constellations of which strikingly resemble the Greek names in form as well as in significance, and the same of the names of the chief planets. Other expressions are found, notably in the works of Vahâra-Mihira, which indicate, if not a borrowing, a contact, at least, with the works of the Greek astronomy, of which Mr. Burgess gives a fairly complete list in his Notes on Hindu Astronomy and the History of our Knowledge of it, in the Journal of the Royal Asiatic Society. Among these terms, some are Greek words which have been utilized in naming constellations or astronomical measures; others have retained the special significations which they had in the works of the Alexandrian astronomers. It would certainly be an exaggeration to insist that the adoption of a foreign term of necessity implies the borrowing of the idea which it expresses. It is, nevertheless, probable that the Sanskrit writers would not have made use of so many of these exotic denominations if the ideas they represent had already found their expression in the languages of India.

Further, among the fine Siddântas which Varâaha-Mihira collected and condensed as including all the astronomical science of his time, there are two, the Romaka and the Pauliça, the names of which suggest directly—the first the scientific culture of the Roman world, and the other Paulus, a celebrated Alexandrian astronomer of the third century A.D.[1]

We apparently find, likewise, the names of Manetho (fourth century A.D.) in Manittha or Manimda; of Spensippus in Sporedjivadja; and of Ptolemy in Asoura Maya, whom the Sounya Siddhânta designates as the founder of astronomy, and who another treatise says was born at Romakapouri, "the city of the Romans."

In this order of ideas the natives of India have never tried to deny their sources. The Gavanas, we read in the Gargi Samhitâ, are barbarians; but this science (astrology) has been constituted by them, and they must be revered as saints. M. Weber affirms that a treatise on astrology bearing their name, the Gavana Castra, was reputed to have been written in the land of the Gavanas by the god Sourya in person, when, expelled from heaven by the resentment of his divine rivals, he came down and was born again in the city of the Romans.[2]

We find, further, that the Greek calendar appears to have survived Hellenic domination in northern India. General Cunningham, in 1862, read in the inscriptions of the Indo-Scythians the names of the Macedonian months Artemisios and Appellaios. Since then the names of two other months of that calendar—Panemos and Daisios—have been found in inscriptions in the Kharosthis character.

Another era of Grecian origin, that of the Seleucidæ, seems likewise to have furnished the Hindus their first historical computation.[3] It should be observed, in fact, that their most ancient era, that of the Mauryas, dates from the year 312 B.C., or the beginning of the era of the Seleucidæ. This had been adopted by the Grecian sovereigns of India, as is attested by a coin of Plato, struck in the year 166 B.C.

Beginning with the Indo-Scythians, India generally adopted the era of the Cakas, which began, not, as had been long supposed, with the expulsion of the Scythians, but with the coronation of their principal sovereign, Kanichka.[4] Nevertheless, the inscriptions offer still other historical computations, as, for instance, that of the Gouptas era, which began in the year 240 of the Caka era, and that of Vikramâditya, which was made to begin retrospectively fifty-six years B.C. Hence arise complications of a nature to make the task of paleography and history no lighter.—Translated for the Popular Science Monthly from Ciel et Terre (from the author's essays on Classical Influences on the Scientific and Literary Culture of India).

  1. The Romaka Siddânta employs, as a measure of time, the Guga of 2,850 years or 1,040,953 days, giving a tropical year of 365 days, 5 hours, 55 minutes, and 12 seconds, which is exactly the figure proposed by Ptolemy and Hipparchus.—Burgess, Journal of the Royal Asiatic Society.
  2. The term Romakapouri does not necessarily imply the city of Rome; the name was probably extended to Alexandria and perhaps also to Byzantium. In other writings we find the name Gavanapouri, the city of the Greeks (or Ionians), applied to Alexandria.
  3. Till then, the Hindus hardly seem to have sought for a common measure of time except for astronomical or mythological purposes.
  4. M. Sylvain Levi has, however, lately reopened the question of the initial date of this era.