The parallels between light and good vs. darkness and evil are stated throughout scripture. Isaiah laments people who try to make you believe that good is evil and evil is good, and who put darkness for light.
We're going to go off the deep end which we found at the bottom of a rabbit hole: we'll draw a direct connection between the Holy Trinity and particle physics. By doing so we arrive at a theory of first cause.
Creation has a purpose which combines the spiritual goal of separating good from evil with the physics of separating light from darkness. It gives us a unified theory of everything within the broad narrative of scripture.
Is the phrase "the heavens shall be rolled together as a scroll" flowery poetic language or accurate physics? If the firmament is a rigid sphere of crystal on the edge of space, it's accurate physics.
Night was the darkness that resulted from the creation of light. Now God has gathered up all the darkness into a ball at the center of a spherical creation so night, technically, is inside the earth at this point.
Christ's sacrificial death on the cross and the darkness immediately after it picture creation in the moments before God said "let there be light" before nucleosynthesis, the fabled "Big Bang."
What if we told you that the world popular science wants you to believe in, an insignificant speck orbiting an insignificant speck drifting through a vast cosmos, is a false narrative of godless existence? Do you even care?