weeelll…a young but brilliant scientist is sent back to “his” era which is the dawn of the technological age. He, knowing what will come, discovers how the nova can be prevented and his children and children’s children create the technology that prevents the explosion.
Maybe.
I’ve had a fan theory* for years that “mirror universes” and other “people are the same despite the world being very different” universes in various settings work by there being some hidden link between them that forces them to remain synchronized in various ways. Like how in a lot of time travel in fiction if you try to change the past events will conspire to preserve the timeline anyway; in the mirror universe events conspire to ensure there are always matching people, if mirrored".
It does make me wonder, if the evil Empire reformed, would that force the Federation to become more evil?
Yeah, I sort of came to that conclusion in the game City of Heroes, with its alternate evil-mirror dimension of Praetoria. Most of the Big Important People have equivalents in both of the universes, even though sometimes they have completely different histories (like, the “primal world” Clockwork King was a mentally delayed but psychic individual who built armies of telekinetic puppets, but the Praetorian Metronome was a genius roboticist who figured out how to upload his consciousness into robots).
Of course, that’s just for the Big Important People (mostly superheroes and supervillains): There can’t be an equivalent of everyone, for the simple reason that over 90% of the population of Praetorian Earth is dead.
The key to the mirror universes is in TNG’s Remember Me.
They don’t really exist. They are the equivalent of stable warp bubbles. And they are created anew every time someone goes to the “Mirror Universe”. You expect to go there, so you do. Which explains why they are the way they are. Sisco’s late wife was alive because he wanted her to be.
This is the secret the Q understand. If humans understood this, everyone could make their own universe and stay in there, forever. Literally: you create a universe where you never die. But humans don’t have enough imagination.
It also explains why the Mirror Universes are always violent, and not the Happy Pink Unicorn with Rainbow Farts Universe. Humans are violent by nature.
eta: this doesn’t explain every detail in every parallel universe ST story. But they’re not consistent now. What are Romulans like in the Mirror Universe? Like the Federation in ours? No one elver said. How about the Husnock? What is the mirror of bland?
My head canon for alternate universes is that it’s easier to cross between realities the more similar they are at the point where you’re crossing. So if you’re going into, say, a world where the Nazis won WWII, you’re more likely to wind up in one that has copies of the main cast your immediate friends/family/coworkers, even if the changes caused by the Nazis winning WWII should have prevented most of them from being conceived in the first place.
BTW there is an excellent Star Trek novel called Crucible McCoy Provenance of Shadows (the weird title is because it was a three book series each a separate story, where one was about Kirk, then Spock then this one was about McCoy). It is set mostly in the alternate history created by McCoy in the beginning of the episode and tells his story of how he lived out his life in the 1930s and beyond before Kirk and Spock changed history back.
That defines “similar” in extremely human centric parameters, but I guess it is not inherently inconsistent.
But maybe it wasn’t the same Mirror Universe! There were two MUs, virtually identical. One was visited by the Enterprise crew, and that one got messed up. Later, the DS9 crew visited the other MU, that had continued as it was “supposed to”, never having been visited by the Enterprise crew.
With infinite possible universes out there, anything is possible. Find one that’s “close enough”.
In the first visit, I believe they said explicitly that the bad state of this universe was the direct result of Spock taking over and not being badass enough.
But that doesn’t mean that there’s only one Mirror universe - just that out of all of the possible Mirror Universes, there’s one that includes a) Kirk’s original trip to a Mirror-verse and b) ends up with a Kira, Bashir and Sisko existing.
I remember hearing or reading once somewhere that a different ending was contemplated for Mirror, Mirror (rather than the one featuring Marlena) that would have implied that Kirk and Co might not have returned to their “home” universe, but one that was “close enough”.
What, did they find a history book that described Nelson Mandela dying in prison?
Alternate universes are canon in Trek, so that’s almost a given.
Oh, there are a zillion (technical term in alternate universe physics) universes that split off from the Mirror Mirror one. The problem is the DS9 people finding the one with all of them. That’s a tiny fraction of the universes.
If I had to justify this nonsense, I’d invent a rule where the pattern buffer in the transporter that lets you cross universes somehow looks for one with similar people to the ones you are sending.
I figure the walls between universes are thin only for universes that look locally very similar.
I recall that in the ST: TNG novel Dark Mirror, it was because of a similarity in exotic-physics “hyperstrings” that were highly correlated between the two universes at a given time and place, and were also involved in the transfer process. One of my favorite old ST novels, too (Mirror!Troi is impressively horrifying as a sadistic empath).
Yeah - an empath as political officer makes great sense for the Mirrorverse
So, kinda like how Rick and Morty wind up on Earth C-137 after Rick cronenbergs their original timeline?
Years ago I read a short story with the idea that travel between alternative universes is so easy that people travel frequently from one to another without even noticing the transfer. That’s why your keys are in your pocket when you wake up, but you distinctly remember having left them on the hook in the kitchen. Or the big branch that landed on your front lawn during yesterday’s storm is still attached to its tree.
And occasionally, you travel to a reality where there’s some really big difference, like Nelson Mandela dying in prison.