Sisko arrived at the end of August 2024. Picard's in April.
Naw, that's not what I meant - I remember that the Defiant was isolated from the changes in the timeline, and I remember they went back to Earth to look for Sisko, and I don't remember if they tried different time periods, but I believe there was a scene where O'Brian and Kira had beamed down to am Earth that was in *our* future (like even *past* 2024, past the Bell Riots) and Kira or O'Brian said something like (paraphrasing) "I knew it was bad back then, but not that bad. Something's very wrong."
I believe this may have been in the mid to late 21st century.
I really need to check a synopsis of the episode.
Also,
@Sci I like your answer, that since the Federation no longer exists in the 24th century, then there was no Picard to go back and visit Guinan and Mark Twain in the 19th century in San Fran.
It would also explain why 25th century Guinan didn't recall meeting Picard ever in the 24th century.
But now, here is the rub...when they get back to the future, will Guinan memories now if having met Picard in the 19th AND the 21st centuries!? Because this does take place *before* the event that split the timeline...so she should retain the memory, because that event also NOW too place in her regular past.
Even if a *human* wouldn't remember,
Guian's seems to have the ability to remember multiple timelines and ate sensitive to changes in. (How much of this is her inborn talent, and how much is residual effects from the Nexus, we may never know.
But I think even a *human* would now remember both sets of memories now, as the timeline has still been changed.
UGH, I *hate* temporal mechanics! A lot of time travel stories seem to involve the concept of not only a maleable past, but also a sort of TIME THAT TIME HAPPENS IN. A sort of...for want of a better word, Ubërtime? (I was gonna call it "Over Time" bit that term has other connotations.)
Let me *try* to explain...so, the FIRST TIME that 2024 ran, there was never any visit of Picard to 2024, but there *WAS* a visit of Picard to the 19th century...but THEN Q changed to present - (He either over wrote the timeline, or He shoved Our Heroes *sideways* in time into a parallel reality that exists somewhere in Probability Space** )...so that "NOW", there is a visit to the 21st century but NOT the 19th...but THEN Picard and Co. will - in the near "Future", fix the discrepancy and THEN, there will be a Picard visit to the 19th century AND a visit to the 21st century.
Even if you can go back and change something from how it happen the *first time* - like I often wish, so badly, that I can go back in time and not be a f*cking IDIOT and go out with this girl who liked me and who wanted to go out with me. Not just because I think it would have worked, and I would have been a happier and better person for it, and because I feel *pain* about causing her pain. I wish I could erase it. Info it. But even if I could go back and redo it all, it doesn't change the fact that there was a version of *her* who, "back then", DID live through that pain - I know, I lived through all that too - so, time has to have a time that time happens. That can never be undone.
Of course this all violates Einstein and Relativity, which pretty much comfirms that the past and the future both ALREADY have happened.
Ugh. The other alternative - and I think likely the truth - is that backwards time travel is just NOT POSSIBLE. AT ALL.
**(In my personal hypothesis about how time works, traveling Forward in Time takes you to the Future, traveling Backwards in Time takes you to the Past, and traveling Sideways in Time is traveling in Probability - or Probability Space. And that is just one axis in Time...there are many...in fact, I think Probability Space, or P-Space, is a type of multidimensional phase space, with many axis, maybe infinite.
Course I not a physicist and so this is all