I have a theory that jughead did in fact go off and the moment before the island was destroyed by the bomb, the force of Electro Magnetism somehow captured that moment in time and threw the entire island (or a copy of it) into a future time period. But it wasn't stable, so Dharma built the Swan and set up the computer programme to make adjustments every 108 minutes, otherwise the world could be destroyed. So for the people on the island at the time, the island wasn't destroyed but moved to a different dimension. But it does not exist in 'real time' and floats around in the future. The time period changes, which is why there are discrepancies and time differences between the island and the real world but it is always in the future as in reality, it was destroyed by the bomb. Sometimes it may be one day ahead of real time, sometimes 10 months, sometimes 3 years, This would explain how the Dr on the freighter was washed up on shore the day before it happened in real time. Anyway, originally, the bomb went off because the leak of radiation made it very unstable but then events were changed because Eloise sent her son to the island (sacrifice) and during the time skips, he told them how to bury the bomb and make it safe and this caused a paradox. To course correct,the bomb still had to go off and that's what happened when Jack etc tried to put Daniel's plan in to action. The EM energy combined with the nuclear reaction, created a window in time. Richard said he saw them all die, I think that he must have seen an explosion at the swan site and may have seen from a distance what looked like our losties all being incinerated, but really they just disappeared and flashed forward to the time period where they were supposed to be i.e. after the Jacob/Flocke finale ("they're coming"). Even if the Swan is never built now, and Desmond not there to not press the button on time, I still think that flight 815 would have crash landed on the island, having flown through a naturally occuring window, but maybe it never broke up. Anyway, can't think anymore on this, it's too late! What do you lot think? Am I theorising too much?