Appendix:
I was recently doing some research and came across a little fact that I thought people might find interesting.
The word "Yom" used in Genesis during the creation and translated as "Day" does not just mean day. It can also be translated as "Time" and "Period" depending on how it is used. Evidently Yom merely means a period of time in which a labor is done. It is usually applied to Day because ones labors are recorded in the Day (morning to night) that they are done. Yom can also mean however a labor in which took months, years, etc until it is finished. “I must work the works of him that sent me, while it is day: the night cometh, when no man can work” (John 9:4). What is more the way that Yom is written in Genesis is missing the necessary prefixes that would specify it to be 24 hour periods or daylight that are found in the remainder of the Bible when used to specify a day and time.
In essence if you go back to the original Hebrew the correct translation would be "period one" (Yom ehad), or the period in which the labors were completed, and not "the first day". In fact it specifically does not even say "First" since the word for one and first (harison) are completely different.
If you want a really in depth article on this specific use in Genesis you can find it
here.