[time anon 1/3] Big question coming, sorry if it's a bit convoluted! When John skipped ahead and doomed the timeline, the Trolls stopped being able to communicate with them. There's only one Alpha Timeline, but is it that only the people in one session get doomed and just go into their own split-off pocket with just them, rather than "one person slips up and everybody in every sburb session going on in that universe is in a doomed timeline now"?
[time anon 2/3] It’s gotta be that way otherwise time players would be like “uh we’ve been doomed 10,000 times by stuff outside of our session”. But there can only be one Alpha Timeline, so how does that work? Is the doomed session simply “cut off” of the alpha timeline, and the individual doomed session alone?
[time anon 3/3] (For this part of the question, please assume that Aranea’s theory that Jake’s hopesplosion could undoom a timeline was true.) If you were to doom Session A and Session B simultaneously, move the players from Doomed!Session B to Doomed!Session A, then undoom Doomed!Session A via hopesplosion, does that mean you’re also undooming a totally empty Doomed!Session B, or does Doomed!Session B’s respective Alpha!Session B (where they never left) keep existing?
I never quite thought of it that way but you know what? That poses an interesting question about the mechanics of Doomed Timelines. It’s true Terezi fucked the Timeline up so that one Timeline was like, an offshot the Trolls couldn’t reach- But shouldn’t there have been Trolls in that Timeline too? There’s two explanations, either indeed the Doomed Versions are ‘cut off’ from the rest of their reality, before fading, or… Gamzee killed everyone, since he seems to go Berserk in Doomed Timelines. So it’s hard to tell which actually happened. It was also early with the Timeline Mechanics, so there’s the possibility Hussie hadn’t settled the bases yet? Hard to tell, I’ll love to read it in the commentary of the upcoming books.
As for ‘Undooming’, the thing is that you’re making too many assumptions. First of all, Aranea’s plan isn’t using Jake’s Hopexplosion, it’s using her own powers. Jake is just a tool to get shit done first. But also, when you ‘Undoom’ something somehow, you Undoom the continuum of the Timeline- There’s not a ‘fixed’ repaired state, what you’re doing is preventing the Timeline from fading. Whatever fucked up stuff happened still happened. You’re just not going to cease to exist. If Undooming even works. So literally nothing would change other than the fact things wouldn’t simply black out.