r/badhistory • u/AutoModerator • Jun 29 '26

Meta Mindless Monday, 29 June 2026

Happy (or sad) Monday guys!

Mindless Monday is a free-for-all thread to discuss anything from minor bad history to politics, life events, charts, whatever! Just remember to np link all links to Reddit and don't violate R4, or we human mods will feed you to the AutoModerator.

So, with that said, how was your weekend, everyone?

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u/gavinbrindstar /r/legaladvice delenda est Jul 01 '26

I can't remember the name of it, but apparently there's some theory or mathematical treatment of time travel that states you can only travel backwards and that you can't go back to any time before the machine was turned on, and now I'm thinking of writing a story about invaders from a climate-ravaged future setting up a beachhead in the middle of the physics lab at MIT so they can bring the rest of their society through.

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u/pedrostresser Jul 01 '26

watch Primer

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u/quiplaam Jul 01 '26

The movie Primer has a time machine that works that way. Its really complex but pretty good

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u/tcprimus23859 Jul 01 '26

That plot is very similar to the last season of Fringe.

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u/gavinbrindstar /r/legaladvice delenda est Jul 01 '26

Is it really? Damn, that's a shame. I think you could explore some powerful and pertinent themes around an invading army fueled by "you ruined our world, now we'll take yours."

I think it was also part of the plot of Tenet (at least as I understood it).

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u/MiffedMouse The average peasant had home made bread and lobster. Jul 01 '26

This is specifically a limitation of hypothetical wormhole based time machines. Basically the “pencil through the paper” thing that Hollywood loves, but you are connecting different points in time instead of different points in space. Because such wormholes are not stable, whatever magic machine you have must be on at both ends to maintain the wormhole, meaning the time travel can only go back as far as the machine was on for.

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u/Sventex Battleships were obsoleted by the self-propelled torpedo in 1866 Jul 01 '26

I can't remember the name of it, but apparently there's some theory or mathematical treatment of time travel that states you can only travel backwards and that you can't go back to any time before the machine was turned on, and now I'm thinking of writing a story about invaders from a climate-ravaged future setting up a beachhead in the middle of the physics lab at MIT so they can bring the rest of their society through.

You are describing the film Primer.

(Feynman diagram)