THE CELESTIAL SPHERE.[ToList]
The outline of this unmapped region must therefore correspond roughly to the horizon of the place where the constellations were originally designed, or at least be roughly parallel to it, since we may well suppose that stars which only rose two or three degrees above that horizon might have been neglected.
From this we learn that the constellations were designed by people living not very far from the 40th parallel of north latitude, not further south than the 37th or 36th. This is important, as it shows that they did not originate in ancient Egypt or India, nor even in the city of Babylon, which is in latitude 32-1/2°.[157:1]
But this vacant space reveals another fact of even more importance. It gives us a hint as to the date when the constellations were designed.
An observer in north latitude 40° at the present time would be very far from seeing all the stars included in the forty-eight constellations. He would see nothing at all of the constellation of the Altar, and a good deal of that of the Centaur would be hidden from him.
On the other hand, there are some bright constellations, such as the Phoenix and the Crane, unknown to the ancients, which would come within his range of vision. This is due to what is known as "precession;" a slow movement of the axis upon which the earth rotates. In consequence of this, the pole of the heavens seems to trace out a circle amongst the stars which it takes 25,800 years to complete. It is therefore a matter of very simple calculation to find the position of the south pole of the heavens at any given date, past or future, and we find that the centre of the unmapped space was the south pole of the heavens something like 4,600 years ago, that is to say about 2,700 b.c.
It is, of course, not possible to fix either time or latitude very closely, since the limits of the unmapped space are a a little vague. But it is significant that if we take a celestial globe, arranged so as to represent the heavens for the time 2,700 b.c., and for north latitude 40°, we find several striking relations. First of all, the Great Dragon then linked together the north pole of the celestial equator, and the north pole of the ecliptic; it was as nearly as possible symmetrical with regard to the two; it occupied the very crown of the heavens. With the single exception of the Little Bear, which it nearly surrounds, the Dragon was the only constellation that never set. Next, the Water-snake (see diagram, p. [200]) lay at this time right along the equator, extending over 105° of Right Ascension; or, to put it less technically, it took seven hours out of the twenty-four to cross the meridian. It covered nearly one-third of the equatorial belt. Thirdly, the intersection of the equator with one of the principal meridians of the sky was marked by the Serpent, which is carried by the Serpent-holder in a very peculiar manner. The meridian at midnight at the time of the spring equinox is called a "colure,"—the "autumnal colure," because the sun crosses it in autumn. Now the Serpent was so arranged as to be shown writhing itself for some distance along the equator, and then struggling upwards, along the autumnal colure, marking the zenith with its head. The lower part of the autumnal colure was marked by the Scorpion, and the foot of the Serpent-holder pressed down the creature's head, just where the colure, the equator, and the ecliptic intersected (see diagram, p. [164]).
It is scarcely conceivable that this fourfold arrangement, not suggested by any natural grouping of the stars, should have come about by accident; it must have been intentional. For some reason, the equator, the colure, the zenith and the poles were all marked out by these serpentine or draconic forms. The unmapped space gives us a clue only to the date and latitude of the designing of the most southerly constellations. We now see that a number of the northern hold positions which were specially significant under the same conditions, indicating that they were designed at about the same date. There is therefore little room for doubt that some time in the earlier half of the third millennium before our era, and somewhere between the 36th and 40th parallels of north latitude, the constellations were designed, substantially as we have them now, the serpent forms being intentionally placed in these positions of great astronomical importance.
It will have been noticed that Ptolemy makes the Ram the first constellation of the zodiac. It was so in his days, but it was the Bull that was the original leader, as we know from a variety of traditions; the sun at the spring equinox being in the centre of that constellation about 3000 b.c. At the time when the constellations were designed, the sun at the spring equinox was near Aldebaran, the brightest star of the Bull; at the summer solstice it was near Regulus, the brightest star of the Lion; at the autumnal equinox it was near Antares, the brightest star of the Scorpion; at the winter solstice it was near Fomalhaut, the brightest star in the neighbourhood of the Waterpourer. These four stars have come down to us with the name of the "Royal Stars," probably because they were so near to the four most important points in the apparent path of the sun amongst the stars. There is also a celebrated passage in the first of Virgil's Georgics which speaks of the white bull with golden horns that opens the year. So when the Mithraic religion adopted several of the constellation figures amongst its symbols, the Bull as standing for the spring equinox, the Lion for the summer solstice, were the two to which most prominence was given, and they are found thus used in Mithraic monuments as late as the second or third century a.d., long after the Ram had been recognized as the leading sign.
It is not possible to push back the origin of the constellations to an indefinite antiquity. They cannot at the very outside be more than 5000 years old; they must be considerably more than 4000. But during the whole of this millennium the sun at the spring equinox was in the constellation of the Bull. There is therefore no possible doubt that the Bull—and not the Twins nor the Ram—was the original leader of the zodiac.