About underwater islands, the submarine and the Swan computer
Here’s something I’ve been thinking about about the whole ‘island submerged under water’ idea.
The island is actually always submerged under water, unless you pass certain coordinates in time and space, in which case you’ll access the island above the sea in a DIFFERENT time and space. The easiest way to do this is through a submarine. The submarine had to go through exact co-ordinates, and, when this was done, you would go through another place and instant in space and time, where the island is not submerged underwater. Likewise, to go back, you’ll need to pass through these co-ordinates again. This is why the DHARMA initiative used a submarine to access the island; they couldn’t have done otherwise. So did Richard Alpert and Ethan to recruit Juliet.
There is another way to access the island; one which is much more difficult. As Eloise Hawking explains to the would-be Ajira 316 survivors, the island is constantly moving through space and time, but sometimes it becomes ‘visible’ just for a short span of time. If you can exploit this short span in spacetime, you can access the island. This is the way Oceanic 815 crashes on the island, the way Ajira 316 crashes, the way Desmond arrives on the island, the way Rousseau and her team arrive on the island, and the way the Black Rock arrives. The freighter people can also access the island through a helicopter that passes through “exact co-ordinates” set by Daniel Faraday, and Michael and Walt can also exit the island if the boat is steered through “exact co-ordinates” that were told by Ben. Note that Desmond said once (while hald-drunk) that he had tried to exit the island at some point, but he ended up ‘going in circles’ and had to go back to the island. He didn’t know the co-ordinates required to pass through in order to exit the island, so he couldn’t exit it.
Now why does Oceanic 815 crash on the island in the original timeline, and not in the alternate timeline? It’s probably because, in the original timeline, Desmond does not manage to type the numbers in the computer on time, while in the alternate timeline, he does. So actually, it’s not the detonation of the bomb that leads to an alternate timeline as such, but Desmond managing to type in the numbers on time. The rules don’t apply to Desmond, so Desmond can retry to enter the numbers on that fateful day! Desmond is the only one who can create an alternate timeline.
To support this theory, notice that, in the alternate timeline, the plane still had turbulence, and the sound during that turbulence was exactly the same as when the massive energy from underneath the Swan was emanating (both in the incident and when Desmond failed to type in the numbers on time). However, in this alternate timeline, Desmond manages to type in the numbers quicker, resulting in the plane NOT crashing.
Long story short: what caused an alternate timeline was not the denonation of the bomb. That was simply the incident as it always happened, as Miles hinted. The alternate timeline is created by Desmond somehow travelling back in time to manage to type in the numbers in the Swan computer on time.

hmm not sure on the Desmond bit, That does not explain why other things on the plane are different like there lives before they get on and the fact that Desmond is on it him self. But I think you are spot on about transportation too and from the island.
yeah i like the idea about the fact that the Island is and always has been underwater, but when we see it underwater, the Dharma baracks are there so does that mean that while all this other stuff is happening to the island that it isnt really and everything is always underwater? plus while the Taweret statue was up that must have meant that there was a giant egyptian head sticking out of the ocean; also there must haver been hints of the massive hills of the island sticking out of the ocean also, so im not too sure about this. but i really hope that the Alt timeline is not the actual one that is the right one, or if it kind of is, has to be linked to the ‘original’ one.
@monkey2music: Desmond may have been a figment of Jack’s imagination
I really like this. The island always being under water is plausible. I don’t know about the Desmond thing though. If he hit the button, then why was he on the plane?
@wanderlust…i like that idea. maybe desmond is dead in this timeline…and is trying to talk to jack hurley-style…
maybe desmond is now smokey and he was just checking that everyone stayed on the plane this time around. i like ur thoughts xactxx on the co-ords and it being underwater but in another reality it isn’t which is how they are on it…..to do with the barracks….we never see the dharma build them they could have been there ever since the island submerged…..the hills and statues head……ur talking about the middle of the ocean here…..it could quite easily fit under sea level……just isn’t gonna go as deep as the real sea otherwise we’d be sat watching it for an hour while the camera travels down to show us.
I agree with monkey2music, Desmond and the numbers did not cause an alternate time line.
I really like this. It is one of the best explainations for why the Island is so inaccesable and difficult to leave from. Also, this would explain the comment that Faraday made about the light on the Island.
I have to agree with the others that the Desmond thoughts are a little shakey but I don’t think that they are inplausible.
Really nice theory.
This is well thought out – I don’t agree with the fact that Desmond was on the Island punching in the numbers though. Im pretty sure that changed.
In terms of the Island always being underwater – definitely plausible. The Island is a very difficult place to get to – especially if it were always underwater. It also makes the location of the Black Rock on the Island possible: For example, the Island was underwater, the Black Rock sinks, and the Island resurfaces with a boat on it.
But…. if the island spends any period of time underwater we would see physical evidence. Like the statue – it was probably have some green algae or barnicles or something on it. What would happen to the Island’s inhabitants? When the Island disappeared in season 4 – did it go underwater? I dont think so; we would have otherwise seen James, Juliet and Co. taking a bit of a swim!
How is it possible for people to live on the island if it is under water?
Also, the alternate timeline can’t have been created by Desmond pushing the button in time because 1) he was on the plane, and 2) there were changes before the flight even took off (Hurley = Good Luck, Jin and Sun = Not Married, Boone = without Shannon)
Jin and Sun were not married in the new scenarios?
When they got stopped at customs the woman called Sun Miss Paik rather than Ms. Kwon.
Hmm i dont know. I like your idea of the co-ordinates but not the Desmond thing because:
1. In the alt. timeline the island is underwater – suggesting this happened in the 70s due to the bomb
2. Des couldnt have pushed the button in the alt. timeline as (like stated above) the island is underwater and hes on the plane.
And hes probably on the plane because when he was doing the race, which brought him to the island in the normal timeline, he just sailed over it.. Which is why i think the bomb explosion caused it.
Plus Juliet said it worked which could be referencing the swan hatch never being built because everyone died and the explosion caused a tidal wave.
@Trinity .. I thought they were married but she wasnt going to help him not get arrested because like before she was trying to escape him? Or did it show a shot of their wedding fingers with no rings that iv missed? or something else altogether lol?
SG – We were probably posting at the same time 🙂
Yeah, at the airport when they’re stopped at customs the woman calls Sun Miss Paik instead of Ms. Kwon.
Ooo did she! good catch there!
@ SG and trinity.. I dont think we can automatically assume that just because Sun’s passport is in her maiden name that she and Jin are not married. Im married, and I still have a passport in my maiden name.
I’d say if we really want to look into this theory, we’d need to check for rings.
If they aren’t married, there’d better be a good explanation for why they’re travelling together!
@brokenankh – I guess it is a possibility that it still says Miss Paik on her passport but this is LOST, the writers went out of their way to have the airport worker say Miss Paik instead of Ms Kwon.
Also, in Season 5 when Sun was stopped at the airport by Widmore I’m sure the airport worker there called her Ms Kwon because it was on her passport.
Ok, it’s been 3 years since Oceanic, but still.
Also, unmarried couples travel together all the time so this shouldn’t matter.