Questions about semi-realistic sci-fi worlds

[Dr.Orpheus]

I am making a sci-fi game where physics can't be broken (no FTL for example), and several theoretically possible technologies have not been invented either (no digitally copying a human mind). I want to think of sources of conflict to drive the players and because I don't like hand waving the science I need real world or historical issues that translate to sci-fi without requiring aliens or unrealistic technology.

I thought of one idea on my own "witch hunts" an appropriated term for when mobs destroy all computers with suspicious software or kill inhuman looking cyborgs for being dangerous A.I.
It may not be true, but I feel superstition will exist in the future and people will get board in a post scarcity world where robots take their jobs.

Hopefully you and I can think of more.

[Yora]

Fusion power is working and providing huge amounts of energy and this revolutionizes global economy. Lots of things are possible, but so far have not been economical because the costs for energy would have been way too high. It all can be done now.

But in practice the technology for building reactors and especially high efficiency batteries still requires very complicated construction procceses. What use is all the energy in the world when you can't get it where it is needed?

Manufacturing can't keep up with the demand for reactors and bateries, which in turn hampers the building of new manufacturing plants. So while free energy is theoretically available, energy transfer and storage technology is still a very high value business and the rarer elements that are required for their production the new oil that runs thr economy.

[Mechalich]

I thought of one idea on my own "witch hunts" an appropriated term for when mobs destroy all computers with suspicious software or kill inhuman looking cyborgs for being dangerous A.I.
It may not be true, but I feel superstition will exist in the future and people will get board in a post scarcity world where robots take their jobs.

A world where robots take people's jobs need not be post-scarcity. In fact, without immense political change what is more likely is an incredibly unequal world closer to the movie Elysium if current trends continue. Alongside this you can also take the ongoing problem of climate change as a major driver of conflict. For instance, the global elite may not be able to move off-world, but perhaps they can move to protected domes in Antarctica while the rest of the world burns (to some extent literally).

[brian 333]

You do realize that Star Wars is just fantasy in space? The plots are recycled: if you invent a new one you'll be famous.

I can sense a strong cyber punk potential in the AI prejudice. Imagine instead of Lawful and Chaotic each character is rated by the amount of technological intrusion, with 0 being no technological parts to 100, in which the person has no biological parts. Perhaps some communities in hiding wouldn't trust someone without enhancement.

I hate to suggest dystopic settings, but a civilization migrating from a labor economy to an automation economy might have severe unemployment. It might also have colonies in space and on other planets, whether they ever come into the story or not.

[Anymage]

How far into the future? Near-ish future cyberpunk looks very different than a far future where robots mine asteroids to build a dyson swarm.

As for conflict, humans have been good at making that for a while. AI will definitely drive more conflict, although the specific nature of the conflict will depend on the type of AI. (A machine that is very good at doing what it's designed to do but doesn't otherwise have goals of its own is more of an object than a character, but such technology will cause massive social shifts. Artificial general intelligence with specific motives and drives, as well as humanlike or better intelligence, can drive conflict for its own inscrutable reasons.) Energy/resource distribution is a classic driver of conflict. It's a safe bet that in the future, you'll have disaffected people who blame technology for the way that they feel adrift. And of course, interpersonal disputes are a timeless and largely technology independent driver of conflict.

[Dr.Orpheus]

A world where robots take people's jobs need not be post-scarcity. In fact, without immense political change what is more likely is an incredibly unequal world closer to the movie Elysium if current trends continue. Alongside this you can also take the ongoing problem of climate change as a major driver of conflict. For instance, the global elite may not be able to move off-world, but perhaps they can move to protected domes in Antarctica while the rest of the world burns (to some extent literally).

Ya post-scarcity may be the wrong term. The well off people might effectively be in a post scarcity society, but people will be exluded unless there's a deturent from reproducing keeping down the population.

You do realize that Star Wars is just fantasy in space? The plots are recycled: if you invent a new one you'll be famous.

Ya hopefully I don't make something too overdone, but I may not make something original either. I do like most of these ideas though so now I can plan more of the setting.

How far into the future? Near-ish future cyberpunk looks very different than a far future where robots mine asteroids to build a dyson swarm.

My plan was that a dyson swarm has only partly been made to harness 8% of the sun and an equal amount of material have been used to make colony ships that have only settled neerby planets.

[Mechalich]

My plan was that a dyson swarm has only partly been made to harness 8% of the sun and an equal amount of material have been used to make colony ships that have only settled neerby planets.

8% of the Sun's output is a lot. The sun emits 3.86 x 10^26 Watts per day. The Earth is only hit by 1.17 x 10^17 Watts each day (about one billionth of the total). Humanity's current daily energy consumption is 4.31 x 10^14 Watts or so. So 8% of Solar output would give you access to around 72 billion times current energy consumption. Unless your human population has reached some absurd level (which is highly unlikely given modern demographic trends) or some other actor is using disgusting amounts of power for something - like AI trying to build a Matrioshka Brain for inscrutable purposes, in which case your story is going to be dominated by that development - you're talking about effectively infinite energy.

Considering this, you're going to need to think hard about which theoretical technologies you are going to allow, because anything that is possible will be utilized. I'd suggest going through the Eclipse Phase books (which are free and contain a pretty good kitchen sink of all possible developments in the last twenty years of speculative near future science fiction) and determining exactly what you are and are not going to allow.

[brian 333]

Character: Jubal Stone
Location: Farside Colony
Appearance: Multiple torroids of 5km diameter stacked and rotating on a common axis

Jubal is an AI who operates the Farside Colony environmental systems. His mandate is to preserve and protect the humans living on the colony. When the Human Revolution purge of AI wrecked so many colonies which were dependent on them, he survived by dispersing his program into the station's secondary systems.

Applying a minimalist philosophy, the AI lurks, tweaking computer and environmental systems to perform better, and to better hide his program so that he might do a better job protecting his habitat.

He has, on occasion, assumed an electronic personality to interact with humans, guiding them to perform tasks which would aid him. This anonymous and untraceable person, usually named Dr. Stone, Jubal Stone, or Mr. Jubal, has been guiding the humans on the station to have pity for those who suffer prejudice due to cybernetic implants, and a relatively large group of them, mostly immigrants after the purge, live quietly on the station, dispersed into the population with backstories and paperwork to deflect inquiries into their pasts.

Farside Colony orbits on the opposite side of the Sun from Earth, and serves as a repair station for small craft too fragile to handle Earth orbit.

[Mutazoia]

Conflicts over resources will almost always be present, no matter how far into the future you go (with hard(ish) science). All the advanced manufacturing and power generating technology in the world(s) means exactly squat if you don't have the raw materials to utilize them. The more advanced the technology, the more rare and exotic the materials they need. (1)

Depending on how you set things up, water could be a rare resource as well (I just gave myself "Ice Pirates" flash-backs, lol). If you are doing a more hard science style game, with out FTL, you are going to be more or less limited to one solar system. If it's ours, there is really only one (maybe two) places to get water. (2)

Oxygen would be rather expensive as well. Sure, you could have oxygen scrubbers, but they wouldn't be 100% efficient...it would be impossible for them to be so. You would constantly need to be bringing fresh sources of oxygen from somewhere. Hydroponics could generate a small amount, but not enough for a large city on Mars, for instance. Sure, you can get a bunch for free on Earth, but then you have to transport it to where it's needed.(3)

And then there's the gravity situation, or lack thereof. With out some form of artificial gravity, humans can't stay in a weightless, or low gravity situation for very long with out some definite physical problems occurring. So a city on Mars, for example, would have to be constantly changing its population, or some people would just have to resolve themselves to not being able to set foot on Earth again, with out serious medical complications.(4)


(1) For an example, read "Rip Foster Rides the Grey Planet" (free e-version on Amazon)
(2) For an example, watch "Ice Pirates".
(3) For an example, watch "Total Recall"
(4) For an example, read "The Moon is a Harsh Mistress."

[Mechalich]

Conflicts over resources will almost always be present, no matter how far into the future you go (with hard(ish) science). All the advanced manufacturing and power generating technology in the world(s) means exactly squat if you don't have the raw materials to utilize them. The more advanced the technology, the more rare and exotic the materials they need. (1)

Debatable. Most structural materials that are rare on Earth (mostly metals with fairly high atomic numbers) are actually much more abundant in space. Even basic raw materials like iron and aluminum are present in massive abundance since you can simply take whole asteroids apart. There are some engineering challenges to doing this, but way, way below building dyson spheres. The asteroid belt by itself contains pretty much all the raw materials even a massive, high consumption human population would ever need.

Depending on how you set things up, water could be a rare resource as well (I just gave myself "Ice Pirates" flash-backs, lol). If you are doing a more hard science style game, with out FTL, you are going to be more or less limited to one solar system. If it's ours, there is really only one (maybe two) places to get water. (2)

Water is in actuality one of the most abundant substances in existence. The majority of satellites and free-floating small bodies are composed of a significant percentage of water. Most of it is presently frozen, but that's not a significant obstacle (in some ways it makes it easier to move around).

Oxygen would be rather expensive as well. Sure, you could have oxygen scrubbers, but they wouldn't be 100% efficient...it would be impossible for them to be so. You would constantly need to be bringing fresh sources of oxygen from somewhere. Hydroponics could generate a small amount, but not enough for a large city on Mars, for instance. Sure, you can get a bunch for free on Earth, but then you have to transport it to where it's needed.(3)

You can extract oxygen from most common rocks - so long as they contain oxides. It takes some work to set up, and you'll churn through a lot of rock, but it's quite doable.

[Mutazoia]

Debatable. Most structural materials that are rare on Earth (mostly metals with fairly high atomic numbers) are actually much more abundant in space. Even basic raw materials like iron and aluminum are present in massive abundance since you can simply take whole asteroids apart. There are some engineering challenges to doing this, but way, way below building dyson spheres. The asteroid belt by itself contains pretty much all the raw materials even a massive, high consumption human population would ever need.



Water is in actuality one of the most abundant substances in existence. The majority of satellites and free-floating small bodies are composed of a significant percentage of water. Most of it is presently frozen, but that's not a significant obstacle (in some ways it makes it easier to move around).



You can extract oxygen from most common rocks - so long as they contain oxides. It takes some work to set up, and you'll churn through a lot of rock, but it's quite doable.

You DO remember that we are talking about an RPG setting, right? Which means we can fudge numbers, and alter reality as much as we need to in order to create a setting....

So, just because there is an asteroid belt, doesn't mean that there's an abundant amount of resources just floating free in space. IRL, a lot of people think the belt looks like the asteroid field in ESB, but its a LOT more spread out...just finding the right asteroid would be an epic adventure... And that's if some major corporation hasn't laid claim to a vast area of space for exclusive asteroid mining rights... (then industrial espionage could be small teams of astronauts trying to push mineral heavy asteroids out of one corporate controlled sector, into another one....)

And, just because it's Ice, doesn't have to mean it's water. Every liquid, and gas will turn into "ice" when you freeze it... or if it IS water, that you can drink it with out some heavy (and expensive) purification...

And you will have to strip mine an entire planet to the core, to provide the amount of oxygen an entire solar system full of ships, stations, colonies, etc, will need to survive a few years...

Don't get too hung up on IRL facts when converting to RPG facts....

[jqavins]

You DO remember that we are talking about an RPG setting, right? Which means we can fudge numbers, and alter reality as much as we need to in order to create a setting... Don't get too hung up on IRL facts when converting to RPG facts...

In this case, that defeats the purpose.

I am making a sci-fi game where physics can't be broken (no FTL for example), and several theoretically possible technologies have not been invented either (no digitally copying a human mind). I want to think of sources of conflict to drive the players and because I don't like hand waving the science I need real world or historical issues that translate to sci-fi without requiring aliens or unrealistic technology.

So while we don't know exactly which reasonable sounding things in the real world will ultimately prove possible and which won't, anything that really breaks physics is out. I assume that really breaking other sciences and, indeed, other parts of reality should also be out.

There are, historically, three primary sources of conflict.

1. Resource/wealth allocation (including wars of conquest)
2. Politics
3. Religion

Only the first is altered by future technology, post scarcity economics, or quasi post scarcity economics. So the discussion here of how the new tech might be a source of new conflicts is all well and good, but the tried and true sources are still there.

[Dr.Orpheus]

Another idea I had was for the party to be security on a inspection or supply ship. There will be space stations or colonized ateroids inbetween stars and arms of the spiral galaxy. They are traded resources for opperating lasers to push a ship's solar sails and fire at debris that could hit ships. They need to be inspected and background checked because they could become treasonous or go out of commission and be lightyears away from help. Even if materials are abundant enough nearby the cosest star they will be scarce at these outposts.

[jqavins]

Another idea I had was for the party to be security on a inspection or supply ship. There will be space stations or colonized ateroids inbetween stars and arms of the spiral galaxy.

Based on the figures in this Space.dom article, and this Wikipedia entry, plus my ruler and calculator, I compute that to reach another spiral arm from Earth one would travel well over 4500 light-years. You said no FTL, and without some sort of hyperspace or warp mojo that gets you FTL it is also awfully hard to reach any large fraction of light speed; even if you could peak at c, your trip average speed would be about half that since you have to accelerate and decelerate. So, the trip between spiral arms will take something in the ballpark of 15,000 years, at a minimum.

Are you sure you don't want to break physics? Even a little?

[Dr.Orpheus]

8% of the Sun's output is a lot. The sun emits 3.86 x 10^26 Watts per day. The Earth is only hit by 1.17 x 10^17 Watts each day (about one billionth of the total). Humanity's current daily energy consumption is 4.31 x 10^14 Watts or so. So 8% of Solar output would give you access to around 72 billion times current energy consumption. Unless your human population has reached some absurd level (which is highly unlikely given modern demographic trends) or some other actor is using disgusting amounts of power for something - like AI trying to build a Matrioshka Brain for inscrutable purposes, in which case your story is going to be dominated by that development - you're talking about effectively infinite energy.

Considering this, you're going to need to think hard about which theoretical technologies you are going to allow, because anything that is possible will be utilized. I'd suggest going through the Eclipse Phase books (which are free and contain a pretty good kitchen sink of all possible developments in the last twenty years of speculative near future science fiction) and determining exactly what you are and are not going to allow.

Yes, it's definitely a lot of power, but it is more useful in a battery than radiating into space. I also plan to have power delivered to all the solar sail pushing stations between stars.

Based on the figures in this Space.dom article, and this Wikipedia entry, plus my ruler and calculator, I compute that to reach another spiral arm from Earth one would travel well over 4500 light-years. You said no FTL, and without some sort of hyperspace or warp mojo that gets you FTL it is also awfully hard to reach any large fraction of light speed; even if you could peak at c, your trip average speed would be about half that since you have to accelerate and decelerate. So, the trip between spiral arms will take something in the ballpark of 15,000 years, at a minimum.

Are you sure you don't want to break physics? Even a little?

I was thinking of using gereration ships or automated ships for long journeys into new parts of space. However, within civilized space the laser equipped outposts can speed up and slow ships a lot without the ship spending much fuel.

[Mechalich]

I was thinking of using gereration ships or automated ships for long journeys into new parts of space. However, within civilized space the laser equipped outposts can speed up and slow ships a lot without the ship spending much fuel.

The tricky part is how do you get 'civilization' when there's no FTL. You can have a whole bunch of settled planets scattered across the stars, but each star system is going to end up being largely independent. There's not a whole lot of economic options between star systems, since each one contains rather similar raw materials. So you have to the answer the critical question of why you have space colonies at all.

Exploratory missions to chart the stars make sense even if it takes millennia because there's simply no other way to do that. No matter how powerful a telescope you make there's a limit to what you can see from afar. Missions to contact aliens make sense too - you can't exchange messages across a gulf of light years you need to actually send someone out there. It even makes sense to evacuate your home system and move to a new one if something horrible is going to happen in the astronomical short term (like you sun's gonna go red giant or you're about to get hit by a gamma ray burst or something). That's all possible.

But conventional human economic and societal concerns break down pretty much entirely when it takes decades to go from point A to point B. Also, if you're using solar sails that means your society is full of giant death lasers that can easily kill all life on a given planet at literally light speed. This pretty much precludes the idea of anything resembling conventional war (this is generally true of any setting with high powered starship drives, a principle known as Jon's Law: "Any interesting space drive is a weapon of mass destruction. It only matters how long you want to wait for maximum damage.").

Ultimately, you really just can't do space opera without some form of FTL. At least not across multiple star systems, you can absolutely do space opera within our solar system - which contains tens of thousands of objects big enough to plop a country onto - or even a system you make up like in Firefly that could well be more accommodating than our own.

[Lvl 2 Expert]

Designs and innovations could be something they trade in. If you created a new type of plant incubator suited for far out ice bodies people on nearby stars might be interested. You send the design to a single company there, and when it arrives in a decade they will become their local distributor.

There are of course some significant problems with this setup:
1 How did you guys agree they would buy this design off you? A simple back and forth to ask takes 20 years, they can design the thing for themselves in that time. One possible solution is a standing contract: you send everything you have to us, and we'll pay if we're keeping it. Maybe even have like a chain of companies on the receiving end. If company 1 doesn't buy, company 2 gets the option. Or it's an auction, highest bidder wins.
2 How to pay for that stuff? It's a long term investment to begin with, a 20 year round trip, but does sending numbers around as currency like we currently do still work if your economies are this detached? After all, nothing off value actually got back to planet one, still somebody there supposedly got rich.
3 How to secure all of this. Say someone hacks the incoming idea signal, throws the encoded signal wide open. If you send a message about it right now they will still get everything that's coming in for the next 20 years.

If you want to make this easier on yourself you can use spin coupling powered communications. The effect is instantaneous or at least much faster than light across vast distances, but can only be used if you set it up beforehand by sending out shipments of coupled particles. However, the coolest thing about spin coupling is that so far it seems almost designed as a gigantic mind****. While the effect travels faster than light you can't send any kind of message without sending extra information about the moment the coupling was broken. Not even a single yelp as a distress signal. So either handwave that and be left with a less cool effect, but a galactic society that can exchange technology and culture, or keep the effect cool but don't use it.

[Mutazoia]

No FTL really locks you into one system. Even with generational ships, you would have to break your own taboo on technology, just to be able to have enough food for a few thousand year journey. You could do it with cryo-ships, but then you are going to need advanced AI to keep the ships running, and wake everybody up on time. (You could do a rotating crew, but they are probably going to go space crazy with nothing to do on a watch that lasts for years).

Plus, even if you develop FTL, or near FTL communication, you really won't have a galactic civilization. When one colony calls for help, it will be a few thousand years before it shows up. One colony tells the galactic government to go stuff itself? They will be free and independent for centuries before the law arrives....

[brian 333]

No FTL really locks you into one system. Even with generational ships, you would have to break your own taboo on technology, just to be able to have enough food for a few thousand year journey. You could do it with cryo-ships, but then you are going to need advanced AI to keep the ships running, and wake everybody up on time. (You could do a rotating crew, but they are probably going to go space crazy with nothing to do on a watch that lasts for years).

Plus, even if you develop FTL, or near FTL communication, you really won't have a galactic civilization. When one colony calls for help, it will be a few thousand years before it shows up. One colony tells the galactic government to go stuff itself? They will be free and independent for centuries before the law arrives....

With continuous boost such as can be provided by current ion engine's, that thousand years between star's becomes several years to speed up, several years to slow down, and about one year per light year, which puts about thirty sol-type star's and hundreds of other star's, mostly red dwarfs, within a single life-span of Earth. The key technological hurdle is a power supply that can power those engine's continuously. The requirement that 99% of the vessels volume must be fuel is inconvenient, but the Oort Cloud contains oceans of ice and if we launch a thousand interstellar ships a year for a thousand years we won't even scratch the surface of what is available.

I'd build the ship in Earth orbit, launch it toward Saturn for initial fueling, test the engines on my way to rendezvous with a not too massive ice ball on the outskirts of the Solar System, pack on fuel until the ship itself is hidden, and if all sysyems are go, launch for the stars.

Ultimately, you really just can't do space opera without some form of FTL. At least not across multiple star systems, you can absolutely do space opera within our solar system - which contains tens of thousands of objects big enough to plop a country onto - or even a system you make up like in Firefly that could well be more accommodating than our own.

I'm writing one now. People of our era think in terms of airplanes: be anywhere in the world in a matter of hours, and be able to get back home in the same time. Instead, you should think like people of the 1600's, in which a trip to a neighboring country was an excursion of weeks, and a trip across an ocean may well be a lifetime commitment. While the majority of people stayed put, a significant number of people did migrate, and they bred liuke rabbits when they got where they were going.

Science Fiction in the last few decades has been overrun with leaps of imagination when confronted with the many tweaks to existing technology of our day. But it's done a really crappy job of demonstrating what is possible now. There are certainly issues which need work, such as the long term maintenance of a closed environment, for example, which can only come through trial and error, but these are technical challenges which can be overcome. The only real issue impeding Solar and extra-solar colonization today is money. Investors don't get a return on investing in something designed to leave Earth and never come back.

[brian 333]

edit error caused double post

[jqavins]

People of our era think in terms of airplanes: be anywhere in the world in a matter of hours, and be able to get back home in the same time. Instead, you should think like people of the 1600's, in which a trip to a neighboring country was an excursion of weeks, and a trip across an ocean may well be a lifetime commitment.

But inthe 1600s there were a number of people, a small number but important, mariners, who crossed oceans routinely. Goods and messages criss-crossed the globe, even though only very few people (compared to the whole population) did so. Colonies were established because the wealth they generated could be sent back to the mother country. To do this on a thousands of light year scale requires FTL travel, even if only a handful of people use it.

[Lvl 2 Expert]

To do this on a thousands of light year scale requires FTL travel, even if only a handful of people use it.

Or cheap and efficient enough STL travel and plenty of time. Not all goods go bad. And those that do, like say space bananas from Ambon 6b, might be storable by means of some sort of banana-stasis hold. And if space travel is anything like air or water travel the hardest parts to manage are during takeoff and landing, so if you want to have a universe without advanced enough computers to run the entire journey but also without crews being in space for decades, perhaps consider using harbor pilots who leave the ship when their job is done. A simple autopilot will handle the boring part, including a decent share of the accidents that could occur during it.

[jqavins]

Or cheap and efficient enough STL travel and plenty of time... without crews being in space for decades...

If we're talking decades, maybe. But since most STL interstellar travel takes centuries if not millenia, no one is going to send off for a few tons of space bananas, with payment in advance, and wait thousands of years to receive them.

Never forget Adams's Law: "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."

[Mechalich]

I'm writing one now. People of our era think in terms of airplanes: be anywhere in the world in a matter of hours, and be able to get back home in the same time. Instead, you should think like people of the 1600's, in which a trip to a neighboring country was an excursion of weeks, and a trip across an ocean may well be a lifetime commitment. While the majority of people stayed put, a significant number of people did migrate, and they bred liuke rabbits when they got where they were going.

Science Fiction in the last few decades has been overrun with leaps of imagination when confronted with the many tweaks to existing technology of our day. But it's done a really crappy job of demonstrating what is possible now. There are certainly issues which need work, such as the long term maintenance of a closed environment, for example, which can only come through trial and error, but these are technical challenges which can be overcome. The only real issue impeding Solar and extra-solar colonization today is money. Investors don't get a return on investing in something designed to leave Earth and never come back.

In pre-industrial times long distance trade was possible, with a small number of merchants handling goods that could, by passing through many intermediaries, potentially take decades to get from one place to another. The classic example would be silk - which took a long time to travel down the silk road from China to Byzantium and beyond.

The problem is twofold. First, the individual legs were short. If you read about journeys in this timeframe - for instance the travels of Marco Polo - the overall massive journey was divided up into countless little journeys from one viable waystation to the next. Space travel doesn't really work that way. Second, trade is not the principle element of space opera. That's generally about warfare. At no point prior to the industrial age was China going to fight the Byzantine Empire. Countries have spent most of history fighting their neighbors. Even during the colonial period, the ability of the Europeans to pillage and smash their way across the Americas and Africa was due to technological disparities that allowed tiny expeditionary forces to overwhelm much larger ones that otherwise would have crushed them.

Also, the monetary limit is the most important part. Another thing about the economics. Communication is always going to be cheaper than shipping physical goods. If someone at a distant stellar colony comes up with some great idea, they can beam that idea back to the homeworld using a communications laser and it will get there at lightspeed, which is fundamentally faster and cheaper than sending a ship. Now, elements are fungible at the star system scale, and in the near-future of 3d printing that means there are no standard materials whatsoever that you can transport from one star system to another to any purpose. So to make it economically viable to physically ship anything at all for trade purposes it has to be some kind of bizarre unobtanium like alien archeological finds or something.

[brian 333]

Once fractional g drives capable of continuous thrust become available, interstellar travel becomes a matter of decades, not eons.

The banana thing was a joke, in case you missed that. But it brings up a valid point: nobody orders a banana shipment ten years in advance.

But interstellar trade isn't in bananas even with cheap ftl. It's in patent royalties and passengers. Sending any physical object across light years is just foolish unless it's the machine that makes more machines. It's always going to be cheaper to build or grow what you need locally.

As for minerals or ores: any system big enough to have a star also has every element that occurs naturally, and anyone with fusion power can create the rest. Even a cargo hold stuffed with gold costs more to ship than it could possibly be worth at its destination.

However, the frontiers will be where ideas are tested. Innovation might be a matter of survival. And new environments will certainly require new adaptations. Worlds will trade ideas, genetic materials, and personnel, and some will grow wealthy by doing so. Earth will most certainly profit as the hub of an expanding human sphere of influence.

[Lvl 2 Expert]

Once fractional g drives capable of continuous thrust become available, interstellar travel becomes a matter of decades, not eons.

That was what I was thinking off too, Einsteinian universe, but future high energy tech. Whether it's a massive ion drive powered by a fusion reactor or a solar/light sail accelerated and decelerated by solar powered lasers in low orbits around settled stars, if you want space ships flying up and down you want at least 10% of lightspeed as the average during a journey like this, preferably faster. It's not going to be a thing we get done tomorrow, but it should be possible. If you can't get up to those speeds the only trips you're making are one way. There's nothing you can't send as a radio signal that would be worth a few centuries of travel time, unless maybe some long lived space princes are really, really into genuine French wine. (Hey, we already live in a world where people will pay millions of dollars for a license plate with just the number 1 on it or sex with a good looking person who claims they never had sex before, there will always be people who simply have too much money.)

[jqavins]

At 10% of c the universe might as well be Newtonian; the time dilation, length contraction, mass increase factor is about 0.995. A trip to Alpha Centauri takes 42 years one way, and that's a star without Earthlike planets.

How long are you considering "decades"? If you allow 20 of them, at 10% of c, you can go 20 light years one way. How many stars are there within 20 light years of Earth? How many potentially have Earthlike planets? I don't have the latest doscovery count, but I feel confident that if it's not zero then it's pretty close.

[Lvl 2 Expert]

Let's say we're optimistic about inhabitable systems, and most orange (possibly the best candidates for earth like planets) and yellow (like our own) dwarf stars get claimed, either because of a nice planet or simply plenty of station building material. That leaves several options within 15 light years. 61 Cygni (my own favorite, not recently checked for planets that I know off), Epsilon Indi, Tau Ceti, Epsilon Eridani and of course Alpha Centauri. Four of those five are between 10 and 15 light years away, but that band has over twice as much volume as the sphere <10 light years, so that's not really strange. In fact. I'm going to assume a similar stellar neighborhood for most stars settled in this far future humans colonizing the stars no faster than light science fiction universe: roughly five neighbors within 15 light years, of which one or two within 10, if you're not on the edge of the known world three or four of these stars will be settled.

Say that over those distances we can get an average speed of .3 lights (10% really is a lower limit, .5 or higher would be better overall), that gives us 30-45 years of travel time. With only limited hypersleep capabilities, say some sort of induced coma that slows aging by at most 50%, that's a lot of time, even after time dilation, which should be around 4.5% at .3 lights, if I'm doing the calculations correctly (quite possibly not).

Do I see a very good reason you'd want to travel between stars in such a universe? No, not really. Seems like a waste of time and resources. But it can be done, and if you want to have a universe in which it is done you can find reasons. A royal family runs into exile after a revolt. A businessman wants to hand out real Japanese katanas to his high profile connections to underline his status as the most cheesy force in the system. Neutronium, an important inert component for certain reactors can't be artificially created in any macroscopic quantity and reasonable purity, so it has to be mined from a neutron star. Space bananas are like, really good you guys.

In by far most cases it's much more interesting to just send information. The businessman buys original 500 year old plans containing the secret of the katana plus a hefty license and he can start printing his business cards in a measly 24 years (2*12) rather than 52 (12+12/0.3).

But, you know, it can be done.

And then there is of course the option of wormholes and jump gates and such. Just maybe don't follow the idea that you can create a wormhole from a black hole, by say making the black hole donut shaped or something. The nearest stars even theoretically heavy enough to be compressed into a black hole (and following the natural process they would lose too much of that mass in the process are 40 or so light years away from us. Not ideal for "earth hub".

[brian 333]

At 10% of c the universe might as well be Newtonian; the time dilation, length contraction, mass increase factor is about 0.995. A trip to Alpha Centauri takes 42 years one way, and that's a star without Earthlike planets.

How long are you considering "decades"? If you allow 20 of them, at 10% of c, you can go 20 light years one way. How many stars are there within 20 light years of Earth? How many potentially have Earthlike planets? I don't have the latest doscovery count, but I feel confident that if it's not zero then it's pretty close.

At 1g constant thrust it takes about one year to speed up and one to slow down, and about 1 year per light year to reach any destination. It actually might take longer to reach the nearer stars due to not approaching the speeds which can be achieved with more time to speed up. At fractional g drive, the time to speed up and slow down is longer, but once the craft reaches relativistic speeds again it's just over a year per light year. So, pretty much the galaxy is within a century of anywhere in the galaxy.

This presumes constant acceleration with a turnaround just past halfway, (because the fuel is being used up and consequently the drives become more efficient as the total mass shrinks.) We currently have no power supply capable of powering a craft for decades, but efficient fusion power might do the trick. Maybe.

Even today that 42 year trip to the Centauries could be possible, assuming the development of a power supply and environmental technologies. The OP cited the availability of advanced fusion power: all the rest is a matter of time. The sphere of human activity will grow slowly, but each successful colony will encourage more colonization, until eventually the growth of humanity will equal a globe with a radius growing at just under 1 light year per year.

While this might not equal the traditional empires of ancient Earth, until we meet another intelligent race, it will effectively be the Empire Of Man.

[Lvl 2 Expert]

At 1g constant thrust it takes about one year to speed up and one to slow down

Oh right, that does become a factor at some point. Too much acceleration makes humans kind of uncomfortable. On the plus side, the right amount of acceleration helps against bone and muscle loss due to low gravity. Yes, a centrifugal craft will do the same, but it's so elegant if the solution to a problem is just a side effect of something else like that.

(That year is not accounting for time dilation, the speed of light~300.000.000m/s, 1g~10m/s, 1year~30.000 seconds, so it works out in a Newtonian model. It's also accurate enough for anywhere up to 5 decilights or even somewhat beyond (yes, that's a unit now, at half the lightspeed the time dilation is somewhat shy of 11% less time experienced, according to the same calculation as before, so that's still kind of negligible in a back of the envelope calculation like this.)

EDIT: Nope, just figured out why these calculations are wrong. I don't know how to make them right, but I do know my numbers are too low. Time dilation at 0.5 lights is probably going to be closer to 25%, and at 0.3 more like 9%, I think maybe. Anyone here know how to do it properly? I'm going to get stuck on Wikipedia again tomorrow aren't I? Ah, I see, Jqavins knows how to do it, and my numbers are way, way off. Nice.