Trope-a-Day: Faster Than Light Travel

Faster Than Light Travel: Means wormholes, which you have to drag to where you want them STL first.  (Or, for transmission only, tangle channels – which, for the physicists reading this, do not work by Quantum Entanglement As We Know It.)  For more details of which, see Cool Gate, Casual Interstellar Travel, and Corralled Cosmos.

And yes, faster than light travel, when combined with appropriate kinds of slower than light travel, absolutely does result in causality violations in the Eldraeverse.  (There are rules to govern which causality violations are possible – of which the short and mostly accurate version is “predestination paradoxes yes, grandfather paradoxes no” and various sophisticated computing techniques – “acausal logic” – make use of this fact.  It’s fun!)  Indeed, sometimes physics students are taken on (lengthy) field trips for the simple purpose of watching effects preceding causes.  It’s a fun day out for all the family!  (Even the ones who may not have been born yet.)

5 thoughts on “Trope-a-Day: Faster Than Light Travel

  1. I’ve been wondering about this – with faster than light travel, if you sent a signal though a wormhole (or whatever means one fancies) so that you could see something happening thousands of lightyears away – wouldn’t it be kind of like seeing into the future? Because you’d be seeing things that otherwise you would only observe thousands of lightyears from now.

    • Yep, it does indeed!

      Even more fun, thanks to relativity, it works that way for physical travel, too – at least so long as your wormholes are fixed. If we dragged a wormhole four light-years from here to Alpha Centauri, every time you stepped through it from here to there, you’d be time-traveling four years into the future, and when you came back, four years into the past.

      (This used to be the case with Eldraeverse wormholes when they were permanent constructions. Trouble is, the physics of that leads to issues like not being able to have cross-links without your wormholes exploding, and lots of similar trouble if you run into someone else’s wormholes, and suchlike.

      So, I figured I’d take one more step back from strictly hard SF there and quietly switch to a model in which wormholes were dynamically established [like, say, Stargate SG-1 wormholes], invented some principles of physics that imply that creating certain types of paradoxes results in exploding mid-transit and coming out the other end as a bunch of radiation, and made one of the most important jobs of the stargates creating an [artificial and rather arbitrary] “empire-time” reference frame so that everyone inside the network can agree on when things happened, and more importantly, in what order.

      Which mostly limits the causality problems and time-travel to deliberate things like the physics field trips, and oddities at the edge of the network – the Worlds and the Republic, fr’instance, won’t agree to share a time-frame in case the other party manipulates it to their advantage, so life can get interesting where the two networks meet. For values of interesting including things like the border war which both sides started first… depending on whose official time-frame you’re measuring history by.)

  2. Yes, exactly! My office mates treated me like I was speaking nonsense, I’m so glad this makes sense to someone else. But what causes the permanently established wormholes explode sometimes?


    • Ah, then we’re getting into exotic bits of physics – of which I can give at best the simplified summary, since, well, I’m not exactly up on the mathematics of this myself. 🙂

      The theory on this – courtesy of Matt Visser – seems to suggest that if you have multiple wormholes which, put together, form a closed timelike curve (i.e, lets you actually loop back into your own past), this lets the virtual particles (which per quantum mechanics are appearing and disappearing all the time everywhere) get into a feedback loop which builds up and up and up until things start going foom. They call that the “chronology protection conjecture”, because it’s the way in which the universe protects itself from anyone trying to build a time machine.

      Which does let you build wormholes, assuming they’re theoretically possible at all, but means they’ll start failing as soon as there are any loops or cross-connections in the network at all. (And since the numbers on how big the bang is when that kind fail is up there in the exploding-stars range… that would be bad. 🙂 )

      It’s a constraint you can work with – I seem to remember the Orion’s Arm writers do just that – but I didn’t think it fit very well with my universe’s other (more story-like) constraints, so I like to assume that the universe is a little more forgiving than that, and will let you build and use time machines. Which is to say, it’ll only blow you up if you actually try and change the past using them, heh.

  3. That’s fascinating, and it leaves me with two questions. Given that chronology protection conjecture were real, would it have existed since the very beginning of the universe by necessity, or could it have evolved? And how many wormholes are required to make such a loop to the past, if more than one?

    I should be looking into more physics to buff up my scifi! But Googling Orion’s Arm takes priority 😉

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