So… a day is really really important to get right … but God didn’t think it was important to make the Sun first … so that all the days would follow from that? So, instead, God goes Four (4) days without the sun … because humans will just “know” what He means?.. even though there was no human alive to see any of it?
Mainly due to tidal effects, the Earth’s rotational period is not constant, resulting in minor variations for both solar days and stellar “days”. The Earth’s day has increased in length over time. This phenomenon is due to tides raised by the Moon which slow Earth’s rotation. Because of the way the second is defined, the mean length of a day is now about 86 400.002 seconds, and is increasing by about 1.7 milliseconds per century (an average over the last 2 700 years).
So the time interval ‘day’ is not even constant If we use it as a precise time interval, do we use year 2000? year 1900? year 33? or the year God spoke to Abraham?
Our use of day, and it appears to be the same in Hebrew, is the interval between events in particular, either successive sunsets, sunrises or noons or midnights… Used this way changes in absolute length are irrelevant. If different events are used, the day length could be different. If it is a time period, then the day of a specific year needs to be specified.
As you can see this last idea can get ridiculous. The Holy Spirit did not give us the information to do this and the Providential One gives us what we need for faith, so to use ‘day’ as precise unit of time measurement must be discarded.