Thank you for the question of the universe before there was the sun and moon, “How did God separate the light from the dark before there was a sun and a moon, according to Genesis 1?”
Before I give an opinion, I would be the first to admit I am not a physicist or an cosmologist. The view express is my own and does not represent other Christians or churches.
Genesis 1:1–8 says this, “In the beginning God created the heavens and the earth. 2 Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters. 3 And God said, “Let there be light,” and there was light. 4 God saw that the light was good, and he separated the light from the darkness. 5 God called the light “day,” and the darkness he called “night.” And there was evening, and there was morning—the first day. 6 And God said, “Let there be a vault between the waters to separate water from water.” 7 So God made the vault and separated the water under the vault from the water above it. And it was so. 8 God called the vault “sky.” And there was evening, and there was morning—the second day” (A searchable online Bible in over 150 versions and 50 languages).
To be fair, I have some presuppositions in regards to Genesis 1:1. Here are my presuppositions:
A. The nature of God is described as light whereby his glory and majesty outshines the sun. Revelations 21 says this, “23 The city does not need the sun or the moon to shine on it, for the glory of God gives it light, and the Lamb is its lamp” (NIV).
B. The declaration that God created the heavens and the earth would imply the existence of something from nothing. It may be at the point of that creation the existence of angels and their dominion over the “universe” and the placement of the earth. It appears that angels have a “light source” or brilliance around them as Isaiah 14:12, II Cor. 11:14).
C. Genesis 1–2 is written from God’s perspective as he “sees/perceives” the universe and earth. The earth is perceived as distant from him and the description of the earth that it is formless and void with a body of water surrounding the earth (Gen. 1:2).
Thus from the earth’s perspective, there is darkness as one looks outward due to the body of water surrounding the earth. Sunlight can penetrate about 3200 ft before it come black (How far does light travel in the ocean?).
With those suppositions, here are my thoughts, just thoughts.
A. God saw the condition of the earth as having no light source being able to penetrate the land mass beneath the water. There was darkness over the surface of the deep which one can interpret that no light source was able to penetrate to the land mass beneath the waters. The Spirit of God was hovering over the waters.
B. God declared the penetration of light source to earth. It is unclear what form of energy is that light. “Light can also be described in terms of a stream of photons, massless packets of energy, each travelling with wavelike properties at the speed of light. A photon is the smallest quantity (quantum) of energy which can be transported, and it was the realization that light travelled in discr’s peete quanta that was the origins of Quantum Theory” (What is Light? – An overview of the properties of light- Oxford Instruments).
One must remember according to the Biblical text, there was no life form on earth to detect the light. Thus the light that is declared is from God’s perspective. Can it be something of his own brilliance to allow “light” to penetrate space to earth or another form of light wave? It may even be that light had not reached earth but with God’s command that light arrived to earth. Whatever that light was, it was able to penetrate space upon earth. God was able to see the light and give that light a name, Day, and darkness, Night.
One may conjecture that the light from Day 1 was permitted to penetrate earth with the waters being separated with an expanse. This may be the first time that light from God entered earth.
C. God made two greater lights: the sun and the moon.
In verse 14, God placed two lights to give give seasons to earth. Those two lights are the sun and the lesser light (moon) to shine on earth. They were place precisely to be able to sustain life on earth. The writer notes that God also made the stars. The debate is whether the stars were made on day four or is a passing notation that the stars were already present. I have already stated my own position.
Thus there were two light sources heading toward earth. The light on Day 1 and the solar light on Day 4. The solar light takes 499.0 seconds to reach earth but the light from Day 1 is unknown. From a scientific point of view, if it is light then it can be detected by our modern instruments as to the particular wave length unless it is an unknown type of light wave. It is my thought that the light from Day 1 flows from God himself to earth that began to reformat life on earth.
SUMMARY: The light from Day 1 is likely to a form of the brilliance of God that penetrated the darkness of space to earth. God directed his light to shine toward and on earth.
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