Implications of Alternate Timeliness

[Aerilon]

A fairly basic question here... Was thinking the other day about time travel (more specifically, alternate realities) within Stargate.

If someone altered a time line for their purpose, would other races (I'm thinking the Nox and Asgard) actually notice, or would they just change with the time line, not knowing any different?

It may also be interesting to ask, whether the 'timeline' that Cam, Sam and co end up in is actually their time linetime line, or simply another parallel universe..?

[Jumper_One]

A fairly basic question here... Was thinking the other day about time travel (more specifically, alternate realities) within Stargate.

If someone altered a time line for their purpose, would other races (I'm thinking the Nox and Asgard) actually notice, or would they just change with the time line, not knowing any different?

I think they wouldn't know

It may also be interesting to ask, whether the 'timeline' that Cam, Sam and co end up in is actually their time linetime line, or simply another parallel universe..?

Sam, Cam and Daniel end up in an AT (alternate timeline), not an AU (alternate universe)

[jenks]

A fairly basic question here... Was thinking the other day about time travel (more specifically, alternate realities) within Stargate.

If someone altered a time line for their purpose, would other races (I'm thinking the Nox and Asgard) actually notice, or would they just change with the time line, not knowing any different?

It may also be interesting to ask, whether the 'timeline' that Cam, Sam and co end up in is actually their time linetime line, or simply another parallel universe..?

Timelines don't change, new ones can be created and old ones can cease to exist but they don't change. It's not clear which way it works, but if you're in a timeline in the SG universe and someone goes back and changes something, then a new timeline will be created and branch off from he point they went back to. As soon as they go back the timeline you are in will either carry on as normal, or cease to exist.

[User45701]

Timelines don't change, new ones can be created and old ones can cease to exist but they don't change. It's not clear which way it works, but if you're in a timeline in the SG universe and someone goes back and changes something, then a new timeline will be created and branch off from he point they went back to. As soon as they go back the timeline you are in will either carry on as normal, or cease to exist.

Thats correct, So whatever happens in the movie it will create a alternite universe that the event are based in ala SGA season 5/6 wont be effected by events in this movie. because i dont understand the concept of multiple timelines existing in the same universe

[Daniel Jackson]

The movie has nothing to do with parallel realities. When Ba'al changes the past, the SGC and Atlantis Expedition never happen. Sam, Cam, and Daniel are traveling back to Earth via wormhole when he goes back in time, so that's why they're protected. Personally, I think this is crap science, but since time travel is still theoretical, it works for me. For the duration of the movie, the SGC doesn't exist or at least not in the way it does in the propper timeline. The Atlantis Expedition never happened, so everyone's on Earth, the Wraith are sleeping, and the Asurans are alive and well and happy to be isolated on their one world. Once SG-1 sets history right, the alternate timeline never happened, and the proper timeline gets restored.

[jenks]

You can't have time travel without alternate realities, going back in time can't magically rearrange ever atom in the universe for you.

[Daniel Jackson]

Time travel and alternate realities are two entirely separate things.

When you go back in time, everything that happens after that is subject to change. If you change the past, the timeline effectively rearranges, as you put it. When you return to the present, everything's different. This all happens in one reallity which is why people say alternate timeline in time travel stories and not alternate reallity.

[jenks]

Time travel and alternate realities are two entirely separate things.

When you go back in time, everything that happens after that is subject to change. If you change the past, the timeline effectively rearranges, as you put it. When you return to the present, everything's different. This all happens in one reallity which is why people say alternate timeline in time travel stories and not alternate reallity.

As soon as you go back in time a new timeline is created, you can't return to the present you left, because that is now either an alternate time line/reality or has ceased to exist altogether. If you change the past the timeline doesn't rearrange at all, as you're not in the timeline you left.

[Daniel Jackson]

Agreed, when you go back in time, a new timeline is created, overwriting the existing one. That's why it's so important to undo an undesirable timeline. Fortunately, it's as simple as going back in time and preventing the other time traveler or your younger self from damaging the timeline. It won't be exact, as the original timeline didn't have people in the past fighting over wether to change the timeline or not, but... as O'Neill said in "Moebius, Part 2," close enough.

[jenks]

Nothing is being overwritten though, the new timeline is separate. If you were in a timeline and someone went back in time, for all we know the timeline could just carry on without them.

[Daniel Jackson]

If someone goes back in time and this timeline contines without them, then they didn't go back in time, they went to a parallel reallity, and that isn't time travel at all.

[jenks]

If someone goes back in time and this timeline contines without them, then they didn't go back in time, they went to a parallel reallity, and that isn't time travel at all.

The new timeline is a parallel reality, it can't not be.

[Daniel Jackson]

Sure it can. The whole concept of an alternate timeline in the context of time travel is that it replaces the existing one. That's why it's a bad event when someone screws with the past. If it were just some other reallity, why would anyone care?

[jenks]

Sure it can. The whole concept of an alternate timeline in the context of time travel is that it replaces the existing one. That's why it's a bad event when someone screws with the past. If it were just some other reallity, why would anyone care?

They wouldn't. The timeline can't be changed, and the only way it can be replaced is if the old one ceases to exist, we just don't know if that is the case. The timeline can't stay linear, it creates all sorts of paradoxes.

[Daniel Jackson]

If the timeline can't be changed, then you're basically saying that time travel is impossible and that the closest we can get is traveling to the past of a parallel reallity. However, this has never happened on Stargate. Time has always been presented as one, singular and alterable timeline. The paradoxes are nullified if you can accept that future elements would remain intact in the past if they arrive before the timeline becomes altered. They wouldn't poof out of existance when the future is changed because they're no longer part of that future.