TenForward: Where Every Vulcan Knows Your Name

Time is a obviously a closed loop. Jeremy Bearimy baby.

When we talk about time travel in fictional universes, almost all of the narratives follow one of three "truths:"

1. Time is one linear thread. What you do now will have consequence X and if you do something different it will have consequence Y. A simple illustration is the movie Sliding Doors. But the same can be said for Back to the Future or Bill and Ted's. If you make a change to the prime timeline, it will ripple into the past/future. Your cousins will disappear from the 3x5 photo!

2. Time has branches, a truly infinite number of universes and possibilities. Really, as far as I'm concerned, the best example of this idea is Rick and Morty. That show has the freedom to both cook our brains about the concept and also hold a mirror to its ridiculousness. You also see it more famously in the MCU, with their multitude of Lokis and such, though the TVA is still hell-bent on a prime timeline. But the multiverse is the natural order, with only 80s inspired bureaucracy to keep it in check.

3. Time is a combination of the two, which leads us to Trek. Time is linear, so Jake Sisko can tell his dad to dodge a beam that travels at light speed. But time is also non-linear, so... I dunno... most of Voyager. When Seven came aboard with her temporal node all bets were off as far as what could even be considered a prime timeline.

Moreso, the mirror universe is a parallel to our own, marching along at the same pace and whose characters are developing at the same rate as the prime timeline. So, there is no prime timeline, and no multiverse. Just the clean-shaven and the goatee universes.

And to answer your question: yes, I think Trek trends toward a "prime" timeline. It's honestly the way our brains work. With all the posturing of the wormhole aliens, we just don't work in a non-linear fashion. And maybe more importantly, good stories don't work that way either, Kurt Vonnegut aside. Time travel is wearing plot armor in EVERY movie and show because no one has a handle on it.

Thank you for bringing this up. It's something I think about too much.

To further illustrate is our Science correspondent ~~Doc Doom~~:

Edit: Egregious error emendation below

Ignoring the one instance of branched time that I know of (the Kelvin timeline), assuming that the prime universe has a single dynamic timeline

What about the "mirror mirror" universe where the Federation never came to be and instead the Terran Empire arose?

There's also time travel in the mirror universe where the USS Defiant (NCC-1764) as seen in ST:Dis (not the Defiant from DS9) was sent to the mirror universe, then also back in time to be found by Jonathan Archer of the prime universe ST:ENT when he was in the mirror universe.

Interesting, I'm working my way through Voyager now, I'll keep this in mind when I run in to those episodes. It makes me think of Stargate Universe too, lots of time travel in that show. They seem to always give you the perspective of the successive version of the group and the "originals" get sloughed off pretty regularly.

OH and the reason they retain certain things after timeline resets like Harry Kim and the slipstream drive could be because one end of the linkage would rot off but the other end would still be kinda connected ?

like depending on where each point of the linkage is, one side could be weaker to paradoxes than the other