Netherworld or night sky?

In Mesopotamian cosmology, the night sky is identical to the netherworld, stemming from an understanding that the celestial sphere steadily rotated from east to west, bringing the heavenly bodies up and down the horizon (Woods 2009: 209). Accordingly, the heaven of daytime turned into a netherworld after the sunset, which was also a form of the cosmological ocean, Apsû, where the stars were thought to originate. During the night, the cosmic order and divine wisdom submerged to occultation into the greater netherworld, not only understood in its grim, infernal aspects, but “in its more complex capacity that encompasses certain pure or ‘blessed’ lands located around the ‘edges of the earth’ as well” (Ataç 2010: 161).—The Overturned Boat, page 40