timeline theory..

[SP90]

Its an endless cycle. You go back to change something which causes your reason for going back to disappear which means you don't go back which brings the reason for going back, back into existence and causes you to go back.

I understand what you guys are trying to say. I personally subscribe to the multiverse theory where every decision that could be made will be made in one universe/reality or another. Therefore the "old Rodney" timeline continues to exist even after Sheppard goes back to change history with his future knowledge. It just boggles the mind to think too much about it. It's a TV show, just enjoy it.

[mike-davies]

Long time GateWorld fan but this is my first post so I’ll try and make it a good one!

It seems that there aren’t too many “Star Trek” fans here because this territory was well explored in Next Generation’s classic episode “Yesterday’s Enterprise” and I have seen no mention of that.

How to explain timelines? Well, firstly, you have to accept that it’s all theoretical as nobody knows whether time travel is possible. Many people believe that it cannot be – the usual argument being the grandfather paradox, that is, if I travel back in time and kill my own grandfather, how am I going to be born in order to travel back in time to kill my grandfather, etc, etc. However, if one makes a leap of faith and accepts that it may be possible, the most commonly accepted “theory” (the basis of many a plot device for SF writers and the one that solves the grandfather paradox) involves “timelines”, different versions of history that hinge on a causal event.

In this case, that event is not Sheppard being thrown 48,000 years into the future – his disappearance would not by itself have made that much of a difference. What does change things is his return to the present with knowledge of Teyla’s whereabouts significantly earlier than she would otherwise have been found (dead) after her baby had been born.

The point is that Rodney’s work in the “original” timeline to facilitate Sheppard’s return would have no effect until it was ultimately successful 48,000 years in the future. For example, it may have not worked because of circumstances that he was unable to foresee – a point that the holographic Rodney acknowledges when he and Sheppard discover that sand has blocked corridors in the lower levels of the city. Had that particular problem not been solved by Sheppard’s hazardous journey through the sandstorm, the “original” timeline would have continued, both up to and beyond Sheppard's arrival in the Atlantis of the future. Remember also that Rodney did not start his work until well after the 12 days that elapsed between Sheppard’s disappearance and his return to the present, thus proving that Sheppard did not return in that timeline.

However, when Rodney’s work was ultimately successful in the future, the effect was to return Sheppard to the present with knowledge of Teyla’s location – the causal event that will change the timeline and, presumably, the fate of the Pegasus galaxy.

The question of whether the “new” timeline will replace the “original” or whether they will co-exist in alternative universes is another matter! Who knows?

Roll on Season Five!

[TheShipper]

To go back a few posts.
They knew Sheppard was sent 48000 years into the future, but they didn't know the exact time he would get there. So if they did use the time-traveling jumper (if it still exists), they wouldn't know when he would appear thru the gate. So they could possibly spend years trying to find him and never succeed.

[bobshort400]

Say you built a time machine in your time line and you wanted to kill Hitler. you would go back in time kill him. then a new time line starts above your time line witch would shift down over you time line and make a new one.
now one would now hilter but you because you are not form the new time line . back to a new future to see what has happen .It 2008 and the us is gone britain rules the would .

ps future can be changed but at a cost, (small or big)