The frame of reference in Ge 1:2 is the Spirit of God hovering over the waters of the earth. The fourth day isn't necessarily the sun being created, it's the sun becoming visible on the surface of the earth after eons of an opaque atmosphere.
This is one of the reasons I don't think it could be six literal days.
The Hebrew word yom, translated as day, has three literal meanings - a 12 hour period, a 24 hour period, and a long indeterminate time. It would be a literal translation to say that the events in Ge 1 took place over six long epochs - notice there is no ending mentioned of the seventh, which we're in...
We are not in "the seventh day." The seventh day of Genesis 1/2 was the first Shabbat (Adam and Eve had been created on Day Six). Unfortunately they sinned and were expelled from Gan `Eiden before they got to experience Shabbat there.