Astronomical Explanation

After I saw the 4500 years old Sumerian Cylinder Seal showing the hexagram surrounded by all the planets I felt the need to find out more about the astronomical angel of the story of this emblem's origin. Here is one such explanation:

Mercury, like Venus has a shorter orbit than Earth; in the case of Mercury, very much shorter. Mercury completes three orbits in just under 50 weeks, so that there are six conjunctions ­ three inferior and three superior in each year. If all six are marked on the circle of the zodiac and the three inferior joined by lines drawn 1-2-3-1 and the three superior joined 1-2-3-1. The result is a hexagram ­ the Star of David or Seal of Solomon. 

The information…came from: Movement and Rhythms of the Stars; SCHULTZ, Joachim (translated by John Meeks);