I'm not questioning that answer, but I wonder why the actual age of civilization would not want to be known. Except, of course, because of the amount of money it would take to re-write history books and stuff like that.
I can see no reasons myself for lying about the age of civilization , however I feel that sciece has it's share of arogant scientists who do not like to be shown up or proven wrong . Which could explain a lot of the things in this story . Interesting link Mystify Thanx... :)