Yeah Loquat, we could get into that debate even though that's way outside anything I'm prepared for. Maybe Sjaak is though.
But why do the scriptures still say there was evening and morning for the first six days, but not the seventh? Even if you wanted to go with the theory that they are not literal 24 hour days, why was the seventh day the only one differentiated?
I'm not saying I know for sure why by any means, but I do think it has significance that the evening and morning phrase was left off for the seventh day other than they were not literal 24 hour days.