by Paul » Sunday 19 October 2003 9:29:45pm
I doubt JK Rowling would have let anyone, even Chris Columbus, know about the prophecy before book 5 was released. Even let her husband, for example, didn't know who the person to die was, so I would guess that such a key element of Order of the Phoenix would have been similarly treated with super-secrecy by JKR.
Having said that, I can't immediately think of exactly what else could be a foggy dark blue sphere. The only other similar thing I can think of at the moment is Neville's Remembrall but that was in Harry Potter and the Philosopher's/Sorceror's Stone, rather than the Chamber of Secrets.