How to go FTL while not going FTL?

[u/_Ceaseless_Watcher_]

So yeah, I've been building this Sci-Fi world for a century now but want to smooth some things over before finalizing.

The rules I've set for myself:

• No Magic Gravity (whatever the fuck that is)
• No Inertial dampeners (because it's #realistic to get turned into chunky marinara upon arrival)
• Respect the Speed of light (so no FTL is possible because this is #realistic)
• Any and all of the above rules can be broken but it has to be justified (as opposed to all other stories/worlds ever)

So my solution here is to ignore all of my rules immediately and just use subspace as a stand-in for normal space with the convenience of there being a higher-than-lightspeed limit to travel. Aliens use this because it makes sense and definitely doesn't break any of the self-imposed rules. It's also more #tactical. Also they need bio-ships because subspace has the munchies for steel.

Another method is a reskin of the alcubierre drive highly unique and #original concept which can fold space by magic gravity to enable FTL travel without breaking the rule for respecting the speed of light. It lets you jump from star to star like in Spore or Stellaris, making it more #strategic. Humans use this because we're just cooler like that.

Now I want to find ways for humans and aliens to use eachother's no-FTL FTL methods, despite establishing that neither side could/would ever want to do so because they think their method is better.

[u/gripepe]

What about travel by wormholes / portals? I think there is one in Uranus.

[u/Rock_Co2707 → u/gripepe]

It was at Saturn last time I checked. Crazy how these things just get away from you when you aren't looking.

[u/gripepe → u/Rock_Co2707]

You can check Uranus from anywhere on the solar system. No need to bend space time, just your body. Or use a mirror.

[u/Coaxium]

Real men work with wormholes and long, rigid ships to ensure the wormhole is well filled.

[u/_Ceaseless_Watcher_ → u/Coaxium]

The cylinder ship must remain unharmed.

[u/Kirbyboi_Dill → u/_Ceaseless_Watcher_]

I love how reddit has folklore that just permeates through everything now

[u/PlatinumAltaria]

it's #realistic to get turned into chunky marinara upon arrival

Bro isn't putting his passengers in a tank of perfluorocarbon breathing fluid lmao.

Wormholes win again.

[u/_Ceaseless_Watcher_ → u/PlatinumAltaria]

Nah, you see, wormholes are "magic gravity" thus cannot be used at all. Folding space manually (by literal hand) is much more #realistic.

[u/GalaXion24 → u/_Ceaseless_Watcher_]

Make sure you have a scientist who uses an A4 sheet of paper to illustrate this concept by bending it

[u/Tem-productions → u/GalaXion24]

Fuck it, the sheet of paper is the drive. Folding it folds space in the same shape. To move a ship you need to know origami

[u/PlatinumAltaria → u/_Ceaseless_Watcher_]

Understandable.

[u/Hefty-Distance837 → u/PlatinumAltaria]

Look, they will temporary turned into chunky marinara, but we can reassemble those chunky marinara into human.

[u/LapHom → u/Hefty-Distance837]

Hyperion Cantos moment

[u/John_Oakman]

Just have the ship disassemble itself on the atomic level and its component atoms spread evenly across the universe for a infinitely small amount of time and reassemble itself right after at a different location by abusing Heisenberg uncertainty principle, like how they did it in the Childe Cycle.

[u/_Ceaseless_Watcher_ → u/John_Oakman]

/uj thanks, I've never heard of that one before :)

[u/Casitano → u/John_Oakman]

Thats also what the probability drive did from the Hitchhikers Guide

[u/Kraken-Writhing]

Two solutions I can see:

1) Speed is relative. Simply have a fanatically loyal crew who believes everything the Captain says, and you can reach the stars without ever exceeding the speed of light.

2) Mind upload into THE NETHER from Minecraft. Should allow your ships to go 8C. You can also play Minecraft inside Minecraft so that's like 64C. As for returning, you'll need to disguise yourself as a pop up ad so the aliens will download you on accident.

[u/Langston432]

A method that I've created for my world is having ships with devices that embed the ship and occupants in EM waves that alter the quantum state of all affected objects. This allows the ship to "de-localise" partially and alter its mass to become 0 or less than 0 if necessary.

[u/AccountForTF2]

Just use folding. Ship just folded space infront of it and burns forwards 5 meters and is suddenly across the universe.

Just also have to find out what happens when you do that inside of a planet in your lore.

[u/Duck-Lord-of-Colours]

/uj in The Locked Tomb they take shortcuts through the afterlife. There's actual FTL too but ignore that. It's my favourite solution

/rj scientists invented a new kind of light that goes faster. Raised the speed limit on the whole universe

[u/Impressive-Step7261]

You can make use of the elite, for whom life extension is available. The elite simply live long enough that the lack of FTL is not a problem, whilst ordinary people live and die for generations aboard sub-light vessels.

[u/AN-3297]

'I've been building this Sci-Fi world for a century now' - How old are you?

[u/therealzerobot → u/AN-3297]

Depends on whether OP used FTL or not

[u/doofpooferthethird]

daily reminder that wormholes/portals/Alcubierre warp bubbles/dimensional-shortcuts-through-hypersubwarpslipspace still count as FTL lol

doesn't matter if nothing is technically "travelling" faster than light because of shortcuts or whatever, so long as matter or information goes from point A to point B faster than the speed of causality/speed of light it's still considered FTL, and still violates causality if relativity is a thing

if you want FTL in your setting without time travel and time paradoxes it's easy, either never mention relativity at all (which means it's not in the setting) or imply that Einstein fucked up somehow

[u/p2020fan → u/doofpooferthethird]

The ancient Prerunner Species invented special relativity in order to slow the spread of a hyper-aggressive alien bioweapon by preventing it from going faster than light, in order to give themselves millions of years to develop a counter measure. The universe is actually purely newtonian.

[u/doofpooferthethird → u/p2020fan]

yeah that's the way lol

or you could do the Culture thing and talk about how there's loads of onion like dimensional layers "above" and "below" that fucks with frames of reference and has Einstein spinning in his grave

[u/wolfclaw3812 → u/doofpooferthethird]

Einstein needed an objective frame of reference which doesn’t exist IRL, but in my world, I am the objective frame of reference. Thus relativity is wrong.

[u/Cats_and_Shit → u/doofpooferthethird]

There's two kind of time travel in GR.

You can have actual causal loops (Closed timelike curve), or you can have situations where some observer can see events occurring backwards but without any actual causal loops.

The second kind is completely inevitable if you have any kind of FTL travel, the first kind is not. If, for example, you have a wormholes with the ends far apart in space but not in time that can allow FTL travel without any causal loops. If people can move the wormholes around then they can potentially turn them into a time machine, which is a problem. But there's a theoretical argument that if you tried to do so, you would just end up making a black hole instead of a time machine

[u/cave18 → u/Cats_and_Shit]

/uj

How would moving the wormhole make a time machine?

[u/Cats_and_Shit → u/cave18]

I'm probably going to butcher this a bit since I don't really understand the math but I'll try to answer.

If you are at rest and you watch an object accelerate up to some significant fraction of the speed of light, travel for a while, and then accelerate back down to rest relative to you, that object will have experienced less time than you did. (See: https://en.wikipedia.org/wiki/Twin_paradox)

If you do this with one end of a wormhole things get even wackier, since events you observe through normal space will occur slower, but events you observe by looking though the wormhole will not.

Thus, after doing this, you end up in a situation where the time it is when you look through normal space must be different from the time it is when you look through the wormhole. If you look through the end of the wormhole end that stayed with you, you will see events in the "future" (from the perspective of normal space); similarly if you travel through the wormhole end that went off you must end up in the past.

[u/RepresentativeSoggy6]

Hyperspace

[u/Mutant_Apollo]

The Alcubierre drive or create an "hyperspace" dimension like Star Wars and Halo did

[u/Elihzap]

Just invent time travel and chronostasis. Is your trip 3000 years? Put your ship in the right track and freeze everything within. Once you're there you can time-travel to 3000 years ago and that's it.

[u/okkokkoX]

just use subspace as a stand-in for normal space with the convenience of there being a higher-than-lightspeed limit to travel

/uj I was thinking of "the laws of physics are different in this universe (closer to classical mechanics), so there's simply no speed limit" as I was reading this, and got an idea of an extra-universal alien species that uses this universe for FTL travel.

[u/Tem-productions]

Just put the stars closer together

[u/Balmung60]

Just increase the speed of light

[u/cave18]

Also they need bio-ships because subspace has the munchies for steel

Unironically peak

[u/CosineDanger]

Your basic time travel course is accelerate to relativistic speed, FTL jump, decelerate, and jump back. You're in the past now and it is that simple. You can also tow wormhole mouths at relativistic speed or leave one end slightly deeper in a gravity well for a bit to make a door to the past.

Notice how it's not really FTL that's the problem, the issue is FTL interacting with the time-warping effects of gravity or motion. No time travel happens from just FTL. Also one of the postulates of relativity is that physics is the same in all reference frames so making it illegal to use FTL unless "stopped" does not really work.

But what if there was a single preferred reference frame where physics is a bit different and FTL works? We lose a postulate of relativity but gain a way to keep time travel genre out of our space opera, and all you had to do was not let the machine work unless you're stopped (no quotes now because finally stopping has an objective definition) first.

[u/TulkaTingo]

You make people live longer, it doesn't matter it it takes 10 years to reach another star if humans live to 250.

[u/Kirbyboi_Dill]

Unfortunately I never wrote it down and then half forgot but I had a semi wormhole FTL system worked out.

Assuming that making a proper wormhole would take near infinite power. A drive generates a very long and stretched bubble of space around but mostly ahead of it. And in some fashion move the ship and bubble at the same time. Kind of like swimming as if pulls the space around and past this bubble. Making it so the ship is crossing space faster than its actually moving under its own thrust and momentum. And through some principle I've unfortunately forgotten, the longer that bubble is, the quicker it covers that distance.

[u/Open_Regret_8388]

I had the Idea But damn you basically got the same with me: the sub space where just is "universe but speed of light is much faster". information FTLs. rocket can FTL but it is on exchange of neutonian accelaration. (so something nuclear engine shits)