A major astronomical series that the Babylonians called "The Day of the Lord" was declared by its scribes to have been copied from a Sumerian tablet written in the time of Sargon of Akkad - in the third millennium B.C. A tablet dated to the third dynasty of Ur, also in the third millennium B.C., describes and lists a series of celestial bodies so clearly that modern scholars had little difficulty in recognizing the text as a classification of constellations, among them Ursa Major, Draco, Lyra, Cygnus and Cepheus, and Triangulum in the northern skies; Orion, Canis Major, Hydra, Corvus, and Centaurus in the southern skies; and the familiar zodiacal constellations in the central celestial band.
In ancient Mesopotamia the secrets of celestial knowledge were guarded, studied, and transmitted by astronomer-priests. It was thus perhaps fitting that three scholars who are credited with giving back to us this lost "Chaldean" science were Jesuit priests: Joseph Epping, Johann Strassman, and Franz X. Kugler. Kugler, in a masterwork (Stem-kunde und Sterndienst in Babel), analyzed, deciphered, sorted out, and explained a vast number of texts and lists. In one instance, by mathematically "turning the skies backwards," he was able to show that a list of thirty-three celestial bodies in the Babylonian skies of 1800 B.C. was neatly arranged according to present-day groupings!
After much work deciding which are true groups and which are merely subgroups, the world's astronomical community agreed (in 1925) to divide the heavens as seen from Earth into three regions - northern, central, and southern - and group the stars therein into eighty-eight constellations. As it turned out, there was nothing new in this arrangement, for the Sumerians were the first to divide the heavens into three bands or "ways" - the northern "way" was named after Enlil, the southern after Ea, and the central band was the "Way of Ami" - and to assign to them various constellations. The present-day central band, the band of the twelve constellations of the zodiac, corresponds exactly to the Way of Anu, in which the Sumerians grouped the stars into twelve houses.
In antiquity, as today, the phenomenon was related to the concept of the zodiac. The great circle of Earth around the Sun was divided into twelve equal parts, of thirty degrees each. The stars seen in each of these segments, or "houses," were grouped together into a constellation, each of which was then named according to the shape the stars of the group seemed to form. Because the constellations and their subdivisions, and \ even individual stars within the constellations, have reached Western civilization with names and descriptions borrowed heavily from Greek mythology, the Western world tended for nearly two
millennia to credit the Greeks with this achievement. But it is now apparent that the early Greek astronomers merely adopted into their language and mythology a ready-made astronomy obtained from the Sumerians. We have already noted how Hipparchus, Eudoxus, and others obtained their knowledge. Even Thales, the earliest Greek astronomer of consequence, who is said to have predicted the total solar eclipse of May 28, 585 B.C., which stopped the war between the Lydians and the Medians, allowed that the sources of his knowledge were of pre-Semitic Mesopotamian origins, namely - Sumerian. We have acquired the name "zodiac" from the Greek zodiakos kyklos ("animal circle") because the layout of the star groups was likened to the shape of a lion, fishes, and so on. But those imaginary shapes and names were actually originated by the Sumerians, who called the twelve zodiacal constellations UL.HE ("shiny herd"):
GU.AN.NA ("heavenly bull"), Taurus.
MASH.TAB.BA ("twins"), our Gemini.
DUB ("pincers," "tongs"), the Crab or Cancer.
UR.GULA ("lion"), which we call Leo.
AB.SIN ("her father was Sin"), the Maiden, Virgo.
ZI.BA.AN.NA ("heavenly fate"), the scales of Libra.
GIR.TAB ("which claws and cuts"), Scorpio.
PA.BIL ("defender"), the Archer, Sagittarius.
SUHUR.MASH ("goat-fish"), Capricorn.
GU ('lord of the waters"), the Water Bearer, Aquarius.
SIM.MAH ("fishes"), Pisces.
KU.MAL ("field dweller"), the Ram, Aries.
The pictorial representations or signs of the zodiac, like their names, have remained virtually intact since their introduction in Sumer.
Until the introduction of the telescope, European astronomers accepted the Ptolemaic recognition of only nineteen constellations in the northern skies. By 1925, when the current classification was agreed upon, twenty-eight constellations had been recognized in what the Sumerians called the Way of Enlil. We should no longer be surprised to find out that, unlike Ptolemy, the earlier Sumerians recognized, identified, grouped, named, and listed all the constellations of the northern skies! Of the celestial bodies in the Way of Enlil, twelve were deemed to be of Enlil - paralleling the twelve zodiacal celestial bodies in the Way of Anu. Likewise, in the southern portion of the skies - the Way of Ea - twelve constellations were listed, not merely as present in the southern skies, but as of the god Ea. In addition to these twelve
principal constellations of Ea, several others were listed for the southern skies - though not so many as are recognized today. The Way of Ea posed serious problems to the Assyriologists who undertook the immense task of unraveling the ancient astronomical knowledge not only in terms of modern knowledge but also based on what the skies should have looked like centuries and millennia ago. Observing the southern skies from Ur or Babylon, the Mesopotamian astronomers could see only a little more than halfway into the southern skies; the rest was already below the horizon. Yet, if correctly identified, some of the constellations of the Way of Ea lay well beyond the horizon. But there was an even greater problem: If, as the scholars assumed, the Mesopotamians believed (as the Greeks did in later times) that Earth was a mass of dry land resting upon the chaotic darkness of a netherworld (the Greek Hades) - a flat disc over which the heavens arched in a semicircle - then there should have been no southern skies at all!
Restricted by the assumption that the Mesopotamians were beholden to a flat-Earth concept, modern scholars could not permit their conclusions to take them too much below the equatorial line dividing north and south. The evidence, however, shows that the three Sumerian "ways" encompassed the complete skies of a global, not flat, Earth.
In 1900 T. G. Pinches reported to the Royal Asiatic Society that he was able to reassemble and reconstruct a complete Mesopotamian astrolabe (literally, "taker of stars"). He showed it to be a circular disc, divided like a pie into twelve segments and three concentric rings, resulting in a field of thirty-six portions. The whole design had the appearance of a rosette of twelve "leaves," each of which had the name of a month written in it. Pinches marked them I to XII for convenience, starting with Nisannu, the first month of the Mesopotamian calendar.
Each of the thirty-six portions also contained a name with a small circle below it, signifying that it was the name of a celestial body. The names have since been found in many texts and "star lists" and are undoubtedly the names of constellations, stars, or planets.
Each of the thirty-six segments also had a number written below the name of the celestial body. In the innermost ring, the numbers ranged from 30 to 60; in the central ring, from 60 (written as "1") to 120 (this "2" in the sexagesimal system meant 2 X 60 = 120); and in the outermost ring, from 120 to 240. What did these numbers represent?
Writing nearly fifty years after the presentation by Pinches, the astronomer and Assyriologist O. Neugebauer (A History of Ancient Astronomy: Problems and Methods) could only say that "the whole text constitutes some kind of schematic celestial map ... in each of the thirty-six fields we find the name of a constellation and simple numbers whose significance is not yet clear." A leading expert on the subject, B. L. Van der Waerden (Babylonian Astronomy: The Thirty-Six Stars), reflecting on the apparent rise and fall of the numbers in some rhythm, could only suggest that "the numbers have something to do with the duration of daylight."