Just a little graphic I made showing Hebrew/ANE cosmology.
Now for an explanation:
The Hebrews believed the sky was a flat plate held up by foundations (2 Samuel 22:8), likely mountains, as shown by the parallel in Psalm 18:7. Mountains holding up the sky can be found in Egyptian and Mesopotamian depictions of the Universe. In other depictions it is air or wind holding up the sky, but even so, the sky needs support. The roots of the mountains stablised the earth as well, as shown in 1 Samuel 2:8, where they are referred to as pillars (Matsuq, a word used elsewhere to refer to mountains). The sun had a chamber which it came out of every morning and entered (the Hebrew word for ‘set’ means to enter) every night (Psalm 19:4-5). There were tow bodies of water, separated by the expanse of the heavens (Genesis 1:6-8), 1 above the heavens, and 1 below. The waters below were a single body which contained not just what we would call seas, but also rivers, lakes, underground springs, and all else. The stars in the firmament were likely seen as responsible for rain in some way (Judges 5:20), and were also seen as living entities of some sort (1 Kings 22:19).
ANE corroboration
Pillars of Heaven and Earth
Victory Hymn of Thutmose III: “I set the glory of thee and the fear of thee in all lands, the terror of thee as far as the four supports of heaven”
Asiatic Campaigning of Ramses II: “I rise like the sun disc and shine like Re, as the heaven is firm upon its supports”
Pyramid text 1208: “Thou art a god who supports the sky”
1 Enoch: I saw the treasuries of all the winds: I saw how He had furnished with them the whole creation and the firm foundations of the earth. 2. And I saw the corner-stone of the earth: I saw the four winds which bear the earth and the firmament of the heaven. 3. And I saw how the winds stretch out the vaults of heaven, and have their station between heaven and earth: these are the pillars of the heaven (1 Enoch)
Epic of Gilgamesh Tablet 9:38: “To Mashu’s twin mountains he came,
Which daily guard the rising [sun],
Who’s top [supports] the fabric of heaven,
Whose base reaches down to the netherworld”
Rig Veda 1.160.4: “Among the skilful Gods most skilled is he, who made the two world-halves which bring prosperity to all;Who with great wisdom measured both the regions out, and stablished them with pillars that shall ne’er decay.”
Rig Veda 6.72.2: “O lords of resplendence and bliss, you bestow light to the dawns; you upraise the sun with his splendour; you prop up the sky with the supporting pillar of the firmament; you spread out the earth, the mother of all.”
Heavenly waters:
Hymn to Aten: There is a Nile in the sky for the strangers
And for the cattle of every country,
That go upon their feet. . . .
Enuma Elish Tablet 5: He split her up like a flat fish into two halves;
One half of her he stablished as a covering for heaven.
He fixed a bolt, he stationed a watchman,
And bade them not to let her waters come forth.