Astronomic explanation of stem & branches theory

What is the astronomic explanation of the stem & branch theory?

This question has been in my mind for long time... There are different sayings about it. Some say that the stems and branches are the vertical and horizontal segments of Heaven, the place between North celestial pole and South celestial pole.  And some people suggest that the stem & branches theory is very deep. It's so deep, that cannot be explained (like Dao), as it surpasses the information not only in time, but also in space and it goes beyond the knowledge of contemporary astronomy and science.

Liang Juchao 梁启超（1873—1929）points out that the 22 characters of the heavenly stems and earthly branches have many similarities with the 22 letters of the Phoenician alphabet.

According to Guo Moruo 郭沫若（1892—1978), the theory originates from Babylon and was later applied in China.

Danny Van den Berghe also gives a good explanation of the arrangement of the stems and branches on the world map. It is very helpful and you can see it here:
http://www.fourpillars.net/pdf/world.pdf