/tg/, how would a setting work that has FTL communications, but only Near Light Speed travel?
Planets can instantly communicate information to each other, but deliveries and transportation are limited by near light speed travel with the associated time dilation "2 months travel through space, 20 years pass where you left".
How would deliveries, travel, immigration, and warfare work in such a setting?
It came upon me when listening to
https://www.youtube.com/watch?v=ud6LiVJkwyA
>>47982146
This is the most classic SF setting, countless authors have described things along those lines. From Le Guin all the way to Simmons, just read /something/.
>>47982146
If you hate yourself, read the Ender's Game series. The first one is ballin'. The ones after that suck ass. But it describes it pretty well.
>>47982448
>>47982980
Thanks for the suggestions anon.
I'm still trying to grasp it.
Like, imagine two planets far away hate the ever loving guts out of each other. One sends a war fleet.
The soldiers feel that 2 months have passed, and then when they arrive. . .what happens?
Has 20 years passed back home, what if peace was declared in those 20 years?
>>47983030
Equip the soldiers with the ftl comms
>>47983030
They find out when they get there. Or they don't, and the war begins again.
We've had incidents like this in real history. It's entirely possible there's still some Japanese soldier in the Ryukyu somewhere who thinks the war is still on, and I wouldn't be shocked if most wars before the start of the 20th century had a few post-treaty battles because of communications failure and sheer distance.
Go read the Dispossessed, The Left Hand of Darkness, or any of the lesser known works in Ursula le Guin's Hainish Cycle, which originated this premise and remains the definitive take on it.
That setting goes roughly like this:
Humanity colonized planets throughout the galaxy sometime in the distant past. Without anything approaching FTL travel, these planets all went their own way and the original civilization fell off everyone's historical record. In fact nobody can even find archaeological evidence of spacecraft so it seems likely the "colonists" were just dumped on alien planets to fend for themselves with nothing more than the odd genetic modification.
At some point in more recent history, someone develops the Nearly As Fast As Light Drive, and interstellar communication becomes at least somewhat practical. From the POV of the traveller, an inhabited planet is a voyage of weeks or months. But thanks to relativistic time dilation, years will have passed on their home planet by the time they've completed a round trip. Large scale trade or warfare is impractical under these conditions, so space travel ends up being all about research and peaceful cultural exchange. A loose federation of space-going civilizations builds up centered around the planet Hain, which ends up as a sort of archive of all humanity, and peaceful interplanetary relations are maintained by nobody wanting to go to the effort of bombing someone for reasons that they'll have forgotten by the time the payload is delivered (also they're careful about vetting new planets to receive the tech). Space travellers are effectively a community to themselves, because once you step outside your atmosphere you're leaving behind everyone you know for (from their perspective) decades.
>>47983196
cont'd
Later yet (why worry about accurate chronology? every planet has their own calendars), Shevek of Antarres invents the ansible, a device that can somehow communicate across space instantaneously. Information is about the only thing worth trading between planets, so of course this is huge and the galaxy enters a new era of commerce between worlds, leading to a loose confederation called the League of All Worlds, or the Ekumen. Space travel explodes, but the only real motivations remain research, tourism and the odd diplomatic contact with new worlds so it takes a particular kind of person to become a starfarer and deal with skipping through time. Every planet can deal with alien immigrants in their own way, but the reality is that the number of people who choose to up and move to another planet is vanishingly small and most of them are career spacers so it really never becomes a problem.
Of course that's one approach, coloured by the author's hippy-ish anthropological sensibilities. She's just not interested in telling stories about mining stars or galactic wars, but just wants to imagine potential human societies evolving in isolation.
>>47982980
>The ones after that suck ass
I disagree. The series goes in a completely new and different direction, but it's never *bad*.
It's really outrageous that none of the popular sci-fi franchises play with this premise, when it's the absolute coolest thing about the idea of space travel. Apparently Roddenberry set out to do it with the original series of Star Trek ("Stardate" was supposed to be ship's time or something) but the writers consistently forgot or ignored so they just said fuck it, let's have the characters run into old flames and mentors and assume everyone's been aging at the same steady pace.
>>47983196
Actually I should correct this, le guin definitely didn't originate this idea. At the very least James Blish had played with it already. "Ansible" is the standard name for an ftl communicator though, especially in a setting with no ftl travel.
>>47983030
You have to find a calculator somewhere to get some scale on that time dilation fascination. There's a huge difference between .9 c and .99 c.
Also remember that acceleration is the key, and mass can offer a much greater effect. If you were to make a close pass around some supermassive black hole like the center of a galaxy then that would dilate your time much more than the same trip out between galaxies.
To bring this in context with warfare as experienced during WW2 or Vietnam, even ship-of-the-line battles, is just ludicrous. It doesn't scale like that.
>>47983489
Hey man, you don't know. Maybe in two or three thousand years we'll have figured out how to continue to grow exponentially. Ships could get real big in that time frame.
>>47983223
Gotta say, I actually really loved Speaker for the Dead even more than Ender's Game. It gets a little too metaphysical beyond there though.
>>47983223
I didn't particularly care for Speaker for the Dead, but I can understand why people would like it. Xenocide and Children of the Mind were garbage, though. I can't believe I actually wasted time reading them. I almost didn't read the Bean series because of my disappointment with them.
>>47982146
Near instantaneous communication with significantly slower travel is exactly how the world works today. It should be pretty intuitive.
>>47983489
>calculator
Here's my personal favourite: http://www.convertalot.com/relativistic_star_ship_calculator.html
At a certain point going faster gains you nothing in travel time, but causes you to a lose a lot of 'real' time. I could see there being a compromise between going fast, and not going so fast that you pop out somewhere 1000 years in the future.
>>47984427
>I could see there being a compromise between going fast, and not going so fast that you pop out somewhere 1000 years in the future.
That's not really how it works, though. If you're traveling 1000 light years at the speed of light, you're going to end up where you're going in 1000 years of real time. Differences in speed affect how old you'll be when you get there, but not how long it takes in "real" time.
So if you go super slow can you go back in time?
>>47984786
>"real" time
I'm sorry, son.
You have failed spacetime 101.
But at least you tried.
Get your hands on The Forever War. Guy lives long enough to become an alien in his own civilization.
>>47982146
Pretty easily, actually, and it's actually likely that's the way it'll go. We could, if we had to, already pretty well do FTL communications- it's just not useful to us on earth.
Communications would be handled via entangled particle pairs, rather than by sending a message. A code system, similar to Morse code but based on quantum state changes rather than on long or short sound intervals, would be created. Then the 'sender' would alter the quantum state of his particle in a coded sequence, and immediately, across any distance, the paired particle on the 'receiver' ship would experience the same changes, allowing the receiver to 'read' the message. We have already generated entangled particle pairs, so this is actually not far at all outside our current abilities.
The best part is that communication by entanglement-based code would be actually INSTANT, regardless of distance. Doesn't matter much here- the speed of light is ~300,000km/s, so you can get an optic signal anywhere pretty close to instantly, at least as far as humans perceive it. But if where you're sending the message is, say, 15ly away, it becomes a real limitation.
Then you just have whatever near-light-speed method of travel you want. You could also theoretically have actual (pseudo)FTL travel using something like an Alcubierre drive or some other spatial distortion based travel method.
>>47984923
This. The Forever War is a really great novel in how it deals with the effects of relativistic travel.
I'll also throw out Vernor Vinges "A Deepness in the Sky"
He writes about the Cheng-ho, a civilization of spacefarers who leap across the ages thanks to time dilation, watching civilizations rise and fall between visits to the same planet (ie, leaving Earth during the Renaissance and going back after thirty subjective years to see 9/11 on TV).
It posits that technology pretty much "levels out" at some point (no FTL or singularity) with planets occasionally falling back into earlier tech levels.
It even has a space war of sorts when two massive research fleets from different civilizations confront one another while checking out an unusual star system. Though the specific hardware isn't detailed much, and nobody really "wins" when they start shooting holes in each other's ships.
Now that I think of it, there's no Ansible, but the Cheng Ho do maintain a network of beacons that give instructions to fledgling technological civilizations on how to jump start basic high tech.
They do this in order to encourage the development of new markets for the really *good* technology they glean from everywhere in human space.
>>47985041
>Communications would be handled via entangled particle pairs
I think that whole theory has been junked.
>>47984825
Actually, no, you have to go faster than light to go backwards in time.
>>47984825
First you have to discover and control negative gravity on the scale of the mass of a few galaxies. But then vacuoles connecting separate times are mathematically possible, according to Einstein. Mind you, the man didn't know everything, he just had a good sense for mentally visualizing complex concepts of physics. And you still have to solve the whole grandfather paradox. But time as such has no direction, that's just us and our idea of linear causality. Physics doesn't mind at all. And doesn't that scare you?
>>47986269
>And you still have to solve the whole grandfather paradox
https://en.wikipedia.org/wiki/Novikov_self-consistency_principle
>>47985041
>Then the 'sender' would alter the quantum state of his particle in a coded sequence, and immediately, across any distance, the paired particle
Doesn't work. Deliberately altering the state breaks the entanglement pairing.
>>47983223
Speaker of the Dead was great, the others were fantasy
>>47982146
There would be basically no spaceships. Basically anything that needed to be done on a different planet would be done via a VR interface and androids.
I've thought about this sort of thing a lot, but mostly in the context of not having FTL communications as well.
I feel like such a civilization wouldn't remain cohesive for long, as interplanetary trade and travel would be unfeasible and mostly pointless. Each planetary system would simply develop their own way, gradually losing loyalties and common laws with their homes. Eventually even history would fade and they'd all become distinct civilizations. Perhaps attempts might be made to keep them unified under a binding rule but it'd be a pretty futile endeavor- sending human troops to re-occupy another star system would require too many resources, waste too much time and ruin the lives of all the soldiers you send, while sending robots would just open you up to killbot invasion yourself and lead to a destructive everyone-loses war.
However if you have FTL then I think it'd be easier to keep shit together. You have the colonies set up to be built upon the framework of the same network, then if any planets step out of line they can just transmit a control signal and take over the colony's AI, forcing the inhabitants to capitulate. The colony could shut off their networking of course but then they'd be missing out on the flow of information like new technology, medicine and scientific knowledge, so they'd be unlikely to do it. You'd end up with these planets full of distinct societies all paying homage to invisible, faraway lords they never see or talk to. It'd be kinda scary really, following the rules because you're afraid of electronic ghosts from the sky.
>>47982146
>immigration
It'd be a hell of a thing.
Just imagine, you decide to move to some new colony, but by the time you get there your skills are 10-20+ years out of date.
That would pretty much cut out travel for fun as well, for most people.
>>47987011
I can weave a throw rug right now with my eyes closed.
>>47983030
>>47982448 said it.
Just read more books you twat.
>>47987105
I think the problem is that on the screen the details of FTL are usually glossed over, or they are understood on a very poor level and used as a plot device, rarely. It's just a topic that gives audiences a headache, movies and shows aren't the media for content like this.
Books can take the time to explain things without becoming textbooks. But who has the time to read with today's attention spans?
