I believe all the events leading up to the incident and the bomb going off all happened in the current time line. Jack and company always go back, Daniel always gets killed, and they always try to set off the bomb when the drill goes too deep. I believe the one difference that is going to change what happens in the future is that Juliet actually survives the fall down into the hole, and detonates the bomb. In the normal timeline the bomb falls down and does not explode, and Juliet falls down the well and dies. When Juliet falls down and dies then the bomb is still at the bottom of the hole and Dr.Chang is able to save it and use it as the fail safe that Desmond eventually detonates. The two scenes of the swan station being destroyed are very similar. In both scenes Juliet and Desmond are very fearful but optimistic, and both believe this is what they are supposed to do. Also, the white flash that appears at the end of Season 5 is the same white flash we see when Desmond sets off the fail safe in the Hatch at the end of season 2. This means that Juliet detonating the bomb is the difference, and that she is in fact the variable that Faraday was talking about.
--Persianduck 19:57, October 14, 2009 (UTC)