Submitted by Dirk Gently on November 22 2000 18:41:28
In reply to How long...? submitted by Sprite on November 22 2000 16:46:27
In answer to your first question, "God only knows."
As to some of the possibilities you mention, check out the sci-fi novel "A Canticle for Liebowitz." I forget who wrote it, but it's a nifty little read.