I'm trying to come up with some ways space travel could be possible in a universe where higher technology exists but isn't widely used. I'm going for more of a fantasy setting here than a scifi one, so magic is used for several of them. Just a couple rules: anything involving wormholes is out, for reasons I'll explain later. Secondly, the people here are terrified of AIs, to the point where any machine in use has to be operated completely manually. Anything that the machine does on it's own is outlawed. So, here are the ideas I have so far. I'd appreciate any feedback or suggestions you might have! One character rides a giant eagle through space. He has a (legal) machine that creates an atmospheric field around them so that they can breathe in space. The eagle has magical properties that allow it to fly extremely fast, so travelling between planets takes hours or days instead of months or years. Dreamers have the ability to astrally project during sleep, and their minds can travel between worlds nearly instantaneously. Cloned and vegetative bodies are kept on each world, which the dreamer can possess in order to have a physical form while they are there. Galleons are the only mechanical ships still available, and they have a bad reputation. Machinery is allowed in this universe, but none of it can be automated. People still tend to distance themselves from technology as much as possible to an almost religious degree. Galleons are operated entirely by its crew, the way an old timey sea vessel would be. That makes them slower and more prone to accidents than magical means, but they're still widely used by the less magically inclined races. Then there are the wyrms. They're a breed of giant reptiles (essentially dragons) that were created to become the primary source of space travel. Their teeth are magical, allowing them to bite straight through space and time, creating wyrmholes that they can simply walk through and come out literally anywhere in the universe. But they underestimated how much damage that would cause to the very fabric of reality, and soon time and space were at risk of collapsing on itself. They began exterminating the wyrms, but some escaped into another plane of existence. They live there now, but occasionally one will chew it's way back into our reality, and intergalactic dragon slayers will have to hunt it down. Anyway, that's why anything involving wormholes is strictly forbidden.
Anything that moves at fast enough speeds to reach other planets/stars within days/hours has to consider Time Dilation. Via the Theory of Relativity and various other cosmological theories, the closer your body's velocity is to lightspeed, the flow of time of the universe around you moves faster. In other words, assuming your body moves at 0.95c, by the time you got to your destination, hundreds to thousands of years could have already passed in real time. Of course, you could just say 'my universe my rules' but I say you would be able to develop your universe better if you consider Einstein's Cage in your setting.
Or maybe another idea. Maybe conceptually it's basically just 'the eagle uses the blessing of travel to move faster than light without actually moving faster than light'. Basically like... I dunno, it dunks itself into a dream world and crosses light years in the blink of an eye, like how you can move really fast in a dream.
Nice thread; given those mechanical constraints I'd be considering ways to slow time in this created universe. Unsure if that conflates with wormholes but this would allow movement through space unlimited by time. If you are talking physical transport through conventional space, given your constraints, yeah, I'm stumped too.
I mean, not everything has to adhere to hard scifi rules, and cosmological theories are kinda out there in popular science understanding. So frankly, I'd say you could just make up whatever magicbabble that works. That said, if you want to emphasise on a worldbuilding element, like the level of technological progress in your setting or how difficult transport is (remember, logisitics can be a useful aspect to consider in the plot), its a good idea to briefly explain and deconstruct the systems at play.
That's a book of conspiracy theories. Why would it help me write a fantasy where people ride giant magical birds through space?
It's actually a book about discovering the reason behind ufos -- ie not a conspiracy theory, but rather stolen Nazi technology from WWII. Also, he meets with several people who discuss potential means of space travel, which currently haven't enough research to say if good or bad. He does mention a couple of conspiracy theories, but the overall gist of the book is weird stuff that one could refer to, to expand the mind and get thinking of weird ideas. I'm not recommending it because it's the best book in the world, but because it's a great starting place for research. Also it talks about a really interesting incident in the beginning where a boat allegedly teleported for a couple of minutes (which he does not support as true) and it is a really fascinating way to look and think about travel. Even if it isn't real (which it almost certainly isn't), then it's something to think about in terms of travel.
If you want your solution to be scientifically feasible there are really three ways to travel to other planets within hours or days that I can think of: Wormholes as you've mentioned Relativistically, if you travel fast enough, for you, hours or days may pass but for everyone else years, decades, or even more may pass (as per time dilation mentioned by @Scarlet-MagicianX26 ) An Alcubierre drive (it basically creates a bubble of spacetime that moves faster than light, but since it's a bubble you don't move faster than light inside it, however, it does require some rather exotic things like negative mass...) Or, you might just determine that there is a way without explaining how... Your question makes me think a bit about a story by Harry Turtledove where FTL travel is a technology that could have been invented by mankind centuries, or even millennia ago but was somehow missed... so when we do discover it, it becomes really unfair when we go out there with nukes to fight spaceships made of bronze... I have only read the one linked story by him but I understand he's written more, but I don't know if he has an explanation for how this work, but if it was possible to do in medieval times, it's likely there's very little high-tech involved in it... (Spellcasting? Counter-balancing of alchemistic pendulums? Weaving of macro-sized string surrogates [maybe what Robert Jordan's Aes Sedai does?]... Tapping into the Electric Universe....? You name it!)
Once you introduce magic, anything goes. Maybe they traverse the Universe Tree that connects all the worlds. Maybe points in space are connected by the Giant Spaghetti Monster and you suck on one end of the cosmic spaghetti and get pulled to the other end. Maybe they build a magic powered rocket ship. Whatever you like best. btw: https://en.wikipedia.org/wiki/Dune_(franchise)#The_Butlerian_Jihad
I've decided that there will also be displacement circles. They work the same way as the Oathgates in Stormlight Archive. Two stone circles, each on a different planet, and when somebody activates them whatever is standing on the circles will immediately swap places. I'm also considering getting rid of traditional spaceships entirely. If I want to go full high fantasy on this, familiar things like that might hurt the setting.
I know that I like pre-existing portals between planets. If they are kept mysterious and not understood by the settings present people then it might save some headache.
Just hand wave it as "magic." If someone is allowed to own a magic eagle, then you've already established magic in your world. It's interesting thought how your world is afraid of tech, but not magic. Why is this? You can also abuse this to get around potholes that come up where you need technology. You can invoke a concept from Carl Sagan (Issac Asimov?) that technology that is sufficiently advanced beyond what you know is indistinguishable from magic. This makes them interchangeable in a story. Check this out: The wizard reached out and touched the crystal ball on his enchanting table. With his touch, the ball began to glow and a low, magical rhythm emanated from the enchanted object. The ancient wizard, chanted a spell, one he'd learned hundreds of years ago by a master sorcerer. "Epa, Toata, Ensa te ma" He peered into crystal, past the veil of the glass and into a portal to spy on his spawns. The old man reached out and touched the screen on his desk. Recognizing his touch, the computer switched on with a light jingle and the screen lit up. The old man, kept youthful by an army of nanobots in his blood, he began issuing verbal commands to his computer. He was taught this system by a teacher in school. "pwd; cd nannycam; nanny.sh" He looked at the screen, keeping an eye on what his children were doing.
A whale would seem more suitable to space than an eagle. But either way, how would they be propelling themselves?
If you're looking for a mechanic to make space travel possible while obeying the theory of relativity, i'd say you need a way to exit the universe. Outside normal space/time you'd be able to move more freely. Kind of like how swimming through a lake is slower than driving around it. If it's not widely used, i'd suggest a simple ship design and fuel the whole thing with magic. A "pilot" with high magic capacity is able to act like a battery for the ship and operate it. You could even have these ships setup in "shipyards" outside of space/time. You just need a doorway of sorts to access it. Just food for thought. I hope it helps inspire.
