PREMISE: When the hydrogen bomb was detonated, the interaction with the electromagnetism moved the island in 1977, such that the butterfly effect of it not being there between at least 1977 and 2004 causes the redemption of the miserable lives of the characters.
"Throw a pebble in a pond, the ripples are small. However, throw a boulder in a pond, the ripples are large." - Faraday, Season 5 deleted scene on blu-ray.
Season 4 Finale - We see that the island can move physically. Also, Eloise Hawkings tells us in the Lamp Post station that the island can move in both space and time.
Season 2 Finale - Desmond turns the key to the hydrogen bomb "failsafe" that interacts with the electromagnetism, the sky turns purple and the high pitched sound is made that we experienced in season 4 finale when the frozen donkey wheel was turned.
Season 4 Finale - The frozen donkey wheel is turned and the sky turns purple, the high pitched sound occurs, and we see the island physically vanish for those outside the blast radius.
Therefore, based on the identical visual and audible effects, it appears that the donkey wheel (an external perspective of how the island moves) and the interaction of radiation and electromagnetism (the season 2 internal perspective of what happens when the island moves) cause the same effect: The ISLAND MOVES.
Season 5 Finale - The detonation of the bomb interacting with the electromagnetism results in the island moving in 1977.
Season 5 - Namaste - Opening Scene - Lapidis is flying the plane at night time. They hit the bumps, and he banks the plane hard to the left. It is so hard that people are thrown to the left of the plane. The flash occurs (i.e., spacial change in location like when the island moved in space) and then we see the plane leveling off from the right to the left in FULL DAYLIGHT (i.e., it made a 180 degree rotation and is now in daylight on the opposite side of the ocean in the Atlantic Ocean).
Season 5 - In the Lamp Post station, we se the pendulum has made marks for the location of the island in both the Pacific and Atlantic Oceans.
Season 2 (I think) - A plane from the coast of Africa running drugs crashes on the island. Now that we know the island can be in the Atlantic at times, this makes sense.
Seasons 1, 4 and 5 - The Black Rock ship is identified as being from England. Before the Panama Canal, this would be an impossible voyage from the Atlantic to the Pacific. However, now it makes sense that the Black Rock could crash on the island if it was in the Atlantic at periods of time.
NOW - IMAGINE the butterfly effect (or Moth effect for Lost junkies) is the island was no longer in the Pacific from 1977 through 2004.....
1. Rousseau would never crash, would give birth to Alex on the mainland, and Alex would likely be attending high school some where in 2004.
2. Desmond would finish his solo race around the world, earn the respect of Widmore, and be married to Penny in 2004 (which we did see a wedding band on his hand on the Season 6 premire on the plane).
Thus, Season 6 is all about the redemptive effect from answering the question, "What if you could change one single event in your live?" As Jacob's tapestry said in the Season 5 finale (the translation): "May you find every desire of your heart." The show has indeed shown the desires of the hearts of each person over the flashbacks.
1. Locke wanted a father.
2. Jin wanted to own a hotel and also deserve the hand of Sun (to be of sufficient social stature).
3. Desmond wanted to be worthy of Penny.
4. Kate (goes back to childhood) recorded on the time capsule recording that she wanted to be with her childhood sweet heart for all time (and possibly a better life for her mother).
5. Hurley wanted to have good luck instead of bad.
6. Sawyer wanted his parents to be alive.
These are all speculative of what will actually be the resolutions. However, something similar is the beautiful ending we will experience as the show concludes.....Redemption and resolution.
Finally, add to the fact that the writers introduced a memory transfer experiment whereby Faraday learned how to transfer memories across time in rats by the combination of radiation and electromagnetism. The two timelines will eventually resolve by the gradual transfer of memories from the 2007 island timeline to the 2004 LA timeline. It might be similar to "Flashes Before you Eyes" where Desmond remembered nothing at first, but as he inches closer toward death, he started to remember more.
I suspect each character will die in 2007 island land, and memories will be transferred to the redeemed lives in 2004 mainland. As the Bible says, "Through giving away your life you will find true life."
But I digress....The island moved in 1977 after the bomb, and wretched lives are in the process of being redeemed in the alternate timeline. Fade to black (or probably white): FOUND, end of show.