And there was evening and there was morning, the first day. Gen 1:5

We think the day starts with dawn, but if you read Genesis 1:1-5, you will realize that God did a lot of creating ( earth, water ) in TOTAL DARKNESS. He did not need Light.

As part of creating a man-habitable planet, Light ( electromagnetic energy and the visible spectrum ) was defined and brought into existence, and with it, the rhythm and pulse of 24 hour time ( Night and Day ). The sun and moon came later!The Jewish night-day system simply reflects an accurate understanding of what comes first. We start in DARKNESS, and then God gives us the LIGHT we need.For it is the God who commanded light to shine out of darkness, who has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ. ( 2 Cor 4:6 )

7 Cogent arguments for a 7 Day Creation
1. A God who can create a universe can easily create a world in 7 days....
2. Plant life needs the Sun to survive. If there was a long time between day 3 ( plants created ) and 4 ( Sun ) - the plants would have died. Not necessarily - but probably.
3. The apparent age of the earth could be a function of effects of the curse ( Adams time ) and the Deluge ( Noah ). I don't mean the earth is 5500 years old, but not necessarily millions of years. All dating methods assume a constant rate of change and do NOT factor any catastrophic conditions that would invalidate that assumption.
4. Weekends! God sanctified a 7th day, not a year, or millennium! Think about that every time you TGIF...
5. The strongest objection is the fact that starlight takes millions of years to reach earth so the universe must be that old at least... Not necessarily- the Bible says He stretched out the Heavens ( they are still expanding ) so it is possible that those light sources were much closer originally ( for the more technical readers - space time distortions around the original "white" hole that created the universe )
6. Night and Day, Sun and Moon created at man-scale, for mans benefit for timekeeping and seasons. Not 1000 year days, but 24 hr ones, and yearly seasons.
7. Every time period in the Bible is man-scale ( Noah's 40 days and nights, ages of the patriarchs from Adam, to 3 1/2 years in Revelation ) Why would chapter 1 be any different?
What do you think?