Genesis 1 New International Version:
2Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.
Darkness was first.
3And God said, “Let there be light,” and there was light.
Light was next.
4God saw that the light was good, and he separated the light from the darkness.
Darkness was followed by light.
5God called the light “day,” and the darkness he called “night.” And there was evening, and there was morning—the first day.
The usage of "night" here was related to the darkness in verse 2. The usage of "day" here was related to the creation of the light and not the sun. Could the first day be defined as a 24-hour earthly period? Here I define the first day as the time elapsed from Genesis 1:2 to 1:5.
In reality, time is not absolute but a relativistic experience that depends on the observer. To my reading, the first day seems far far shorter than 24 hours.
Related question:
Assessments of the evidence for the "Gap Theory" reading of Genesis 1:1-2? This one questions geological time over the 6 days of the creation process and Gap Theory. My question has nothing to do with the Gap Theory. I'm not interested whether there was nap time or not between Genesis 1:1 and 1:2. I'm interested in the possible relativistic time elapsed between Genesis 1:2 to verse 5.
P.S. I am not trying to impose science on the Scripture. I'm trying to reconcile them when I can. When I cannot, I always put more weight on the Scripture, thinking that the science needed will catch up with it in the future :)