Timeline branching going forward *spoilers*

[F. King Daniel]

This is why we fans can't have nice things.

 

[Sindatur]

More to the point, we have no idea whether the events of "Relativity" are themselves occurring in an alternate timeline because it's only discussed subjectively.

In other words, while they exist in a timeline in which the Borg interfered with "First Contact", we don't know whether it was the Borg of their timeline that interfered or whether it was Borg from a different timeline that did so. And if you believe that when you travel into the past you jump tracks, then the latter must be the case.

Any of the possible results are possible. It won't always necessarily be an "alternate timeline is created when you travel back in time" in Trek, it won't always be "possible to change the past" nor will it always be "Impossible to change the past". Any of these three possibilities may happen when Trek does Time Travel, we've seen examples of all of them.

 

[DonIago]

I agree.

Given that Data established that individuals have quantum signatures that can be used to establish their timeline of origination, in-universe I would imagine that these quantum signatures might be tested after any incident during which individuals might have jumped tracks, to establish that they were where they were supposed to be.

 

[Opus]

First Contact' changes Zephram Cochrane, who talks about a future with Robotic Zombies. One could say the universe Picard and crew returned to in the 24th Century was no longer the Prime Universe.

It sure looked like the same universe to me. There's no evidence anything was changed there either.

And the Universe that had Captain Picard eating Vanilla cake at Worf's birthday party looked awfully the same too.

Except it wasn't.

The post-'First Contact' had a Zephram Cochrane that talked about killer zombie cyborgs in the future.

 

[Mr. Laser Beam]

The post-'First Contact' had a Zephram Cochrane that talked about killer zombie cyborgs in the future.

And how do you know the pre-FC didn't also include that? As has been said before, it could be a predestination paradox. Meaning, there was never a timeline when it did not happen. You can't prove that this was not the case.