I realize I'm slow but what other light source is there besides the sun. The blue sky is only seen as blue when the sun is up - or close to the horizon. The moon only shines because of the sun. The stars are not much in the way of light givers - the moonless night sky is often referred to as being pitch black and won't make the sky very blue even with a full "milky way". And with no sun it would be this way always.
In all sincerity, I may have missed the meaning here. Wouldn't be the first time. lol
Hi knock knock....Thanks for your question. I would just like to first point out that the ancient Hebrews did not know anything like we do today about the refraction of light in the atmosphere, the fact that "moonlight" is reflected sunlight, or that the brightness of the sky depends on that of the sun. The moon in Genesis 1:16 is referred to as a "lamp" or "luminary" just the same as the sun and stars. The sky was believed to be a domed vault that was stretched over the land like a tent (cf. Job 9:8, Psalm 19:1-6, 104:2, Isaiah 40:22, 42:5, 44:24, 45:12, 48:13), and a similar notion appears in older Canaanite mythology (e.g. KTU 1.5 i 4-5 which says that when Baal smites "Lotan, the fleeing serpent, finishing off the twisting serpent, the close-coiling one with seven heads, the heavens wither and go slack like the folds of your tunic," compare the almost verbatim parallels in Psalm 102:25-27, Isaiah 27:1, 34:4). Within this tented vault, the luminaries rise and run forth through the sky like champion runners (cf. Psalm 19:4-6, and especially the Book of Luminaries in 1 Enoch); again heliocentrism is a modern cosmological concept that is foreign to Hebrew texts.
The Priestly narrative in Genesis 1 construes the luminaries as placed within the vault or expanse (v. 14) and above them lie the "waters" from the primeval deep that were raised up to form the tent-like dome; the expanse "separates the water under the expanse from the water above it" (v. 6), and it is the same place where birds fly (v. 20). In Job 37:18 the spread-out heavens are said to be as "hard as a mirror of cast bronze" (indeed the Hebrew word for "expanse" comes from a root meaning "to hammer out") and elsewhere in the OT the firmament is often described as bright, as shining forth light from God. Job 26:13 claims that "by his [God's] breath the skies became luminous". In Ezekiel 1:22 the firmament is described as "sparkling like ice and it is awesome", and the righteous are said to "shine like the brightness of the heavens" (Daniel 12:3). Psalm 104:2-3 presents a poetic creation account in which God "wraps himself in light as with a garment and stretches out the heavens like a tent and lays the beams of his upper chambers on their waters". Notice that it is on top of the suspended waters forming the vault of heaven that God is described as building his abode. The light from God is probably construed as shining through the firmament, making it luminous and sparkle (cf. the comparison in Job 37:18 of the heavens to a mirror). There are later variants of this notion; the firmament in Revelation 4:6 is described as a "sea of glass like crystal", while Josephus refers to the firmament over the expanse of heaven as "crystalline" (Antiquities 1.30). In the Testament of Levi, "there is much water suspended" in the first heaven and above this there is "a second heaven much brighter and more lustrous" (2:7-8).
There are also a number of other texts about God being enthroned on top of the waters above aside from the statement in Psalm 104:3 that God "lays the beams of his upper chambers on their [the heavens'] waters". Psalm 29:10 says that "Yahweh sits enthroned on the primeval ocean" and Job 22:12-14 states that "God is at the zenith of the heavens and looks down on the highest stars ... as he goes about on the vaulted heavens" (cf. Isaiah 40:22). Rain occurs Yahweh opens up the "windows of the heavens" (cf. Genesis 7:11, 8:2, 2 Kings 7:2, 19, Isaiah 24:18, Malachi 3:10), and this is probably dependent on the older Canaanite idea that Baal causes rain to pour down by opening up windows at his heavenly palace: "Let a window be opened in the house, a casement in the midst of the palace. Baal opened a rift in the clouds, his holy voice Baal gave forth, Baal repeated the issue of his lips (i.e. thunder)" (KTU 1.4 vii 26-30).
So as I mentioned previously, the way the cosmos is conceptualized in Genesis 1 is best apprehended by taking the text on its own terms and seeing how it corresponds to similar concepts in the OT, rather than trying to anachronistically impose a modern scientifically-infomed understanding of the universe on the text.