For example the Hebrew "Ha Yom" -- "The Day", by itself refers to Yom Kippur, the yearly judgement day. In that regard a day is a judgement cycle. Day and Night -- in that context could be understood as the processes of discovery/observation and deliberation/analysis. The old saying "Let's sleep on that." applies to difficult,. weighty decisions. So in the context of OOD, "day" could refer to a judgement cycle object.
You and Race have been discussing the "day" as the solar day experienced at a place on Earth. That is alternatively 24 hours, or a full solar period. The two are not the same, and certainly the length of a solar period has changed -- as recently as the giant tsunami--causing earthquake.
Either "day-concept" could be generalized under OOD as a day object. Under a "24 hour day" concept, we can still have very long long days -- say if we were to place our clock on the super-fast spinning edge of a black hole.
All this is to suggest that one should not limit one's understanding of what "day" means, and one CAN somehow fit accurate scientific observation -- Truth of one form, to the Book of Genesis and the other four Books, Truth is another form, and more Truthful form. Yet it is obvious from history and current discussion that such "fitting" engenders emotional discussions, contentions that are very difficlt to settle, and thus may not be a productive use of one's relatively short time in existance.
"Either "day-concept" could be generalized under OOD as a day object."
Class Cast Exception! You should use the Calendar object here, or if nothing else, java.util.Date.