Blimey. Absolutely brilliant everybody, keep it up. I'll have to re-read A Brief History of Time again just to keep up. I really don't understand how time travel can be possible because if one travelled back in time and then changed the past the whole issue could be completely different. We would possibly be living different lives, presuming we were born at all. But we must have been, in order to travel back through time in the first place. See what I mean?