The whole question of the actual, temporal length of a Biblical day in Genesis seems like a futile pursuit. The early part of Genesis is clearly metaphorical (even poetic). I don’t think the author intended the wording to set a thousand mathematicians in action.
The author was God and as I indicated just before this post ... the following applies ...
— — —
If something is in Scripture ... this applies ...
2 Timothy 3:16-17
16 All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness,
17 that the man of God may be complete, thoroughly equipped for every good work.
Trying to turn the book of Genesis into a modern science textbook is indeed futile. I have a Roman coin and I am supposed to believe it is 30% of the age of the universe. Really? Dinosaurs coexisted with people. Really? The tectonic plates don’t exist and the continents were moved to their current place in a 40 day flood. Really? Just about everything you see when you look at the night sky is an illusion. Really? God made everything to falsely appear older than they are as some test of faith, I guess.
Two different threads with the same title and I think they reference the same work.
The Age of the Universe
http://www.freerepublic.com/focus/f-news/1576941/posts
http://www.freerepublic.com/focus/religion/3051495/posts
There’s no reason to think that the first part of Genesis is metaphorical.