May 16th, 2012 05:45 pm (UTC)
The number 12 in astronomy and myth
I appreciate your article.
Here is a thought for why the number 12 was so important to ancient astronomers (we would call them astrologers, today), and to ancient religions (we would call them myths, today).
The sky was seen as a revolving dome with stars upon its surface. There were 7 'stars' or heavenly bodies that could be seen with the naked eye that moved independently across the surface of this starry dome. These were called the 'wandering' stars, or 'planetoi' in Greek. We call them planets today. The Romans called them 'angelus', the 'messengers', which gives us our word angel.
The 7 planets were seen to travel at different speeds. Ancient sky watchers realized that the planet moving with the highest apparent speed must be closest to the observer on Earth. The slowest moving planet must be furthest from the observer on Earth. Each planet was thought of as being attached to its own revolving dome or sphere in the sky. Since the spheres could be seen through, and an observer could see the next higher layer, the spheres must be clear, made of crystal. Thus the story comes down to us of the 7 crystal spheres of heaven, or the 7 heavens.
The planets were ranked according to their apparent distance from Earth. Mercury (fastest, and thus closest, and so the swift messenger of the gods), Moon, Venus, Sun, Mars, Jupiter, Saturn (farthest away, and so cold and dark). There was some debate in ancient times as to the proper order, with several different versions surviving down to modern times.
The revolution of the planets was the best way to keep track of time. An observer merely waited for the planet to return to the same point in the sky. The days were given by the movement of the Sun. The months by the movement of the Moon.
The cycles of Venus were used by Aztecs and Mayans to calculate proper times for war.
The planet Jupiter was hailed as the king of the gods by the Greeks and Romans and Babylonians. The planet Jupiter takes 12 years to perform one revolution in the sky, dividing the sky into 12 discreet sections of 30 degrees each.
The retrograde motion of Jupiter even neatly subdivides the sky into smaller sections of 10 degrees each. By watching Jupiter, such a brilliant and slow moving marker, it is easy to keep track of time. This was crucial in an era when there were no clocks, and the local calendar was always based on the reign of the local king. Only by keeping lists of kings was it possible to keep track of the years. But... each hamlet and city state had its own king. The only way to have an agreed upon time calendar with any other city or state was to use the well known markers of the heavens as the basis. Once you knew the movements of the planet Jupiter, and related it to any of the kings in the list, you could accurately track time.
Any self respecting sky watcher studying the heavens would have to have a book of kings, and a list of the 12 positions in the sky that Jupiter traveled through.