Post US/EU air dates I am done with spoiler tags. If someone comes along and explains that I still need them I will add them.
When the bomb went off did it create another time travel event?
The scenes showing all the passengers landing at LAX, I assume that is some sort of alternate reality.
Yes, a secondary (the producers are avoiding use of the term alternate in interviews) time line. I will chart this to help me explain it.
Pardon the Paint work
My guess here is that the past cannot be changed in the traditional sense that we think of it. There is no single time line that can just be altered. What has happened has happened and any time traveling done to change events will essentially just create a new time line.
So, the bomb went off in the 70s and did destroy the electromagnetic anomaly (I assume) and created a new (red) time line, and at the same time the effect put our Losties back in "present" day 2007 on their original (blue) time line.
Now, when Juliet was dying she rambled on about coffee and going dutch. And then Miles claimed that her dead talking said "it worked." Maybe the coffee talk was a reference to her and Sawyer's past that we never saw, or it was a red 2004/2007 crossover. I don't know. But the "It worked" thing makes me wonder if dying in the blue time line doesn't put you in the red time line, at least metaphysically. Perhaps that is why in the red time line Jack seems out of it. Maybe he never gets to rejoin that time line?
Anyway, there are a lot of changes in red 2004 that are not the same as blue 2004. I can explain most of them in a way that makes sense with the story's continuity. The one that doesn't is the missing Shannon, but we do not know to what degree her back story was affected by the island's presence. If anyone has any questions about the 2004 red vs blue changes lets try to work them out. Anything I missed might be a clue to something I am missing and vice versa.
We know that Locke is not obviously the real one but something has taken control of his body and killed Jacob. Is the thing that took over Jacob his nemesis (the guy who was sitting with him on the beach).
Yeah, "Locke" is the MiB, and MiB is also the monster. That's pretty clear now. I'm not sure if the plane scenes are an alternative reality, it could be flashbacks (well, flashforwards) since this was always present in the series.
The producers have called them flash-sideways and have basically confirmed a second time line.
http://popwatch.ew.com/2010/02/02/lost-premiere-damon-carlton/
What about Sayid being revived, and why is it so important that he survives? Maybe he's the link to kill the MiB like Locke was used to kill Jacob?
My theory is similar, but different. Jacob and the MiB are different, even if they are of a similar nature (Gods? Good & Evil incarnate?). The simple reaction that Jacob became Sayid seems too obvious for this show. I do not think Sayid was ever completely dead. Remember Miles sitting next to him and someone (Hurley?) asked what he was thinking and he says, "Nothing." Dead Sayid was not talking, because he wasn't dead. I don't think that Jacob's better nature allows him to do things the way MiB did.
But, MiB did not take Locke's body, just his form. So, it is possible that Jacob must "posses" a body while MiB is a shape shifter that needs a body he can take the form of.
I just still can't imagine Jacob completely taking over a body like that and the whole Miles "Nothing" thing tells me that isn't what happened. I could almost see Jacob in more of a God role using angels. I picture Sayid being empowered as an archangel to lead the battle against evil.
But there was a very resurrection-like scene. A middle-eastern man is submerged into water and "dies" and he is spread eagle as he is lifted out, only to rise up again. Looking at this religious imagery is almost painful. what if it is a more Father/son/holy spirit thing? Jacob does enter Sayid, but he is also separate, like God/Jesus?
Or maybe there s some Egyptian mythology that I am unaware of?
I will have more info tomorrow night, I believe.