Lost--the end begins (spoiler alert)

Ha, okay, so I stole that from Salvation, but who cares?

Okay, so how crazy was last night? I have physics issues with the way this time travel is working. I figure there are three possibilities, two of which assume time is linear. In the first assumption, there is a single line, and if you can jump back in time, you always jumped back in time, and you can't change the past because the past is immovable. However, this would set up a looping issue and preclude free will. I don't like that.

The second assumption, time is linear, but a new ray can start. From the moment, Sawyer and Juliet and the others went back, they started a new branch, an alternate future, where everything changes and they can, possibly, stop the plane crash. However, since we've been watching the non-time traveling Losties, this makes this impossible because they're on the same ray (because of the picture Sun saw). They're still following the original track where nothing in their history has altered--or maybe it has, and we just haven't been able to perceive it. I don't know. Anyhow, both seem unlikely.

The third assumption is that, like Farraday said originally, they didn't just travel in time--they traveled in space. Which seems more physics-likely. That means the past they went to wasn't the past, but a past, maybe a parallel but non-intersecting past. But the photo of them in the 70s that Sun found kind of ruins that too because it shouldn't directly affect her present unless when she and the others crashed, they crashed into that same alternative reality as the 70s Losties, but that reality's future, so she still remembers her past, but it's not the past of the reality she's in. That seems unlikely, though.

So all of those logical possibilities are tossed out the window. We haven't seen off-islanders since they went back, so maybe time and space and consequences differ between the island and the rest of the world. Maybe things change off-island, but not on, or vice-versa.

Next, Locke isn't Locke! Obviously! How did we not figure that out? The actual Locke would not want to kill Jacob. Duh. Is Jacob really dead? Is Locke the permanent realization of that guy on the island with Jacob when the Black Rock approached? What is Jacob? Clearly, he's some kind of divine entity or an extension of the island...but he seemed to bleed like your average guy.

And then, Juliet. Is she going to be like Desmond now? Was that her eye in the promo for 2010?

Let's say it does have a pure reset, which seems impossible. Are we gonna see the people from the plane who died in the first few seasons?

I have more thoughts, but...mostly I can't believe we have to wait to 2010 to see how the writers turn ALL THAT into a satisfying final season.