The idea that the balls are reflecting the postions in the sky explains the many balls of Mercury, a highly irregular planet.

Number 7 could be a sign for Mercury.

In the Gilgamesh epos the 'twin' heroes overcome the terrible ogre Huwawa / Humbaba, the god of storm or god of air. An appropriate description for a god placed between the sky and the earth. 'Enlil has appointed him [Huwawa / Humbaba] as a sevenfold terror to mortals... his roaring is (like that of) a flood-storm, his mouth is fire, his breath is death!' (Hamlet's Mill)