Originally posted by Sinai:
Verses 3 and 4 tell us that God is responsible for light, that He made light, that God saw the light (and that it was good), and then "God separated between the light and the darkness." One of the reasons I find that phrase especially interesting is that it almost exactly parallels modern scientific thought about what happened after the Big Bang.
Both the Talmud and modern cosmology indicate that the first light (verse 3) was of a nature so powerful that it would not have been visible by humans (had there been any around to observe it). Although science has theorized that the "light" of that early period was in the energy range of gamma rays, as the thermal energy of the photons fell to about 3000 degrees Kelvin, electrons could bind in stable orbits around hydrogen and helium nuclei, and light separated from matter and emerged from the darkness of the universe. Thus, at that moment the light became visible.
It might be noted that this is also consistent with Isaiah 45:7, which says, "I [God] form light and create darkness." The Hebrew hoshek used in Isaiah 45:7 for "darkness" is a created--possibly the created--substance of the universe.
Thus, light would have preceded our sun by billions of years, and the Bible would be correct in placing the separation of light and darkness as having occurred on yom one, while the sun did not become visible from the Earth until the fourth yom.