Yuan,
If you read the text carefully, light was being separated from darkness as it was being created. The darkness was over the land / earth but we must bear in mind the issue of perspective (like sun rise etc). Given the illusiveness of the nature of light to fall into any known category, particle or wave both and neither... it is apparently the stuff in common with both the universe and eternity.
I know this sounds like a page right out of Star Trek... but bear with me...
What the humanists behind those TV scripts call parallel universes, the Bible calls eternity / heaven / the spirit realm.
Colossians 1:15 Who is the image of the invisible God, the firstborn of every creature:
16 For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him:
17 And he is before all things, and by him all things consist.
18 And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence.
We in the physical, finite universe think of things needing a source (like birth for example... it is difficult to imagine God always existing without beginning or end). So to presume light has to come from stellar bodies alone is really a rather simple approach to a very complex and illusive subject (light).
What we perceive as light is a reflection (if you will) of the nature of another realm (heaven). Here it is like a universe filled with candles, in heaven it is what eternity consists of. And the Genesis account was more or less the creation of the capacity for the physical to accommodate the spiritual. I think of it more or less like God breathing life into the universe... which was until that point a lifeless hulk.
It was this process that started the cycles of nature etc. not that the universe is a living being but is alive in the sense that plant life is... if you get my meaning.
So, "let there be light {here}" imho would be a fair (if not accurate) interpretation... the sources of current light being mere candles compared to stars... and the 24 hour "day and evening" simply mean the earth was already in a rotation aspect to the vent of light from the other realm.