In the beginning, God created the universe. Before that, there was nothing — not even an infinite galaxy of darkness, which would be something. God must have been around before the beginning, but it’s not something he likes to talk about.
At first the earth was without form. Everything was dark and void. This was apparently depressing to God, so he said, presumably to himself, “Let there be light!” And a light appeared. It wasn’t the sun, though. God waited a few days to create the sun. At this moment he needed a special light for creating other things before the sun.
When God saw this light, he thought it was good. It wasn’t too dim or too bright. No adjustment was necessary. God decided to separate the light from the darkness, though, calling them “day” and “night.” Apparently they were all tangled up at first, causing a sort of swirl effect.
On Tuesday God decided to divide the waters, so he said, “Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.” God called the firmament “heaven.” Many years later, people on earth would start calling it “outer space.”