God intends to bring about a permanent physical separation of light from darkness. Light weight and light bearing are synonyms, like dark and heavy are. In general heavier, denser materials are darker.
Physical Separation
Light and Darkness
On rare occasions we encounter someone who has an inkling of what we're doing, harmonizing science with the Bible, and they ask an intelligent question about it. The intelligent question was this:
A space between: בֵּ֥ין – bayin
Dividing the water above the firmament from the water below below it required physical space. Likewise, dividing the light from the darkness isn't the alternation of day and night, it's also the their separation by a physical space.
February 9th
In pondering the physics of creation we have come to understand that the earth is part of the ongoing process of the permanent physical separation of light from darkness. The process is not complete. Yet.
December 5th
The permanent physical separation of light from darkness, good from evil, starts by causing darkness to accumulate at the center of creation. It's what we're made of. Light is on the periphery.