In my view the first chapter or so of Genesis was a revelation to people who wanted an explanation of their origins and of the universe as they knew and understood it. It was not intended to be a scientific text. However I had a Biology professor who explained that the days of creation as outlined in Genesis first chapter were not simply the days of our calendar here on earth.
Also consider the meaning of the Hebrew word for "day":
The word "day" (Hebrew: Yom = יוֹם) can hold one of several meanings and is used variably within the Bible.
[2] The exact definition of the word is derived from the context in which it is used by the author. Several of such meanings include:
- A general or vague concept of time.
- A period of a year.
- A period of light in a day/night cycle.
- A period of 24 hours.
- A specific point in time.
Days of creation - CreationWiki, the encyclopedia of creation science