It's generally cheaper to make it at home, but when we can reach another star, what non-magical pressure would make that not true for humanity? There exist small niche markets in wine and some lumbers on earth, where the resource requires a very long time to be produced. An example is the eucalyptus boon in the early 20th century, when American entrepreneurs hoped for cheap lumber by growing eucalyptus. They discovered that the wood is completely useless from a tree under 150 years old.

My story begins with our human society (on earth), near future. There exists something in another system that cannot be cheaply produced in our solar system (because many things the universe makes simply can't be replicated in a lab, or not in bulk). Because of this and advancements in antimatter propulsion, trade with an interstellar civilization became economically favorable. We have instantaneous communication with their civilization however mass still obeys relativistic laws. We trade at 0.1c by unmanned barges back and forth, three barges per year each way. The supply route takes 200 years between stars.

We can fill our own demand for what this system has

Given that we have affordable access to another star system as described here, what socioeconomic pressure would cause humanity to commoditize an interstellar resource?

Their commodity is a resource which can not be made in volume AND is either:

  • Required for human society to continue it's standard of living
  • Required for the continued health of humanity
  • Required for the continued habitability of earth's environment
  • Required for the economic health of human society
  • Required to maintain a cultural addiction in human society

Note: This world has no hypothetical technologies beyond what is described here or in my world links. No bio-engineering, no FTL, no warp technology, no fusion drives. All known science is as it is in reality with few exceptions. Fictional science is limited to the following:

  • The predictions in PT (Parity-Time) Symmetric theory of quantum mechanics are true, and the the no-signaling principle in quantum mechanics is unnecessary and invalid.
  • Non-carbon based life evolved on another world
  • Antimatter containment in large scale is possible with Minimum Magnetic Field Traps
  • 2
    $\begingroup$ Ugh, we have a huge market in a commodity with lead times measured in decades: wood. There are hundreds of millions of hectares of managed plantations in this world. If the distant aliens can send us wood, we would love to buy it with a lead time of 200 years, especially if they arrange the transports to come year after year after year; after all, that's not so much different from the regular 20 or 40 or 50 years lead time between planting a tree and harvesting the wood. $\endgroup$
    – AlexP
    Mar 8, 2022 at 0:57
  • 5
    $\begingroup$ It looks like you're asking an open ended question where you're asking to generate ideas for you. Such questions tend to have many equally valid answers and aren't a good fit for this site. $\endgroup$
    – sphennings
    Mar 8, 2022 at 3:19
  • 1
    $\begingroup$ I’m voting to close this question because it's simply too vague. We don't know what the commodity is - but we're asked to suggest reasons why a dependency on the commodity might come to pass. That feels very much like you're asking us to write your story for you. So, VTC:Needs Details (completely explain what the commodity is before asking why humans would be dependent on it) and VTC:Too Story-Based (because why anything happens is always dependent on your story). $\endgroup$
    – JBH
    Mar 8, 2022 at 5:59
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    $\begingroup$ @VogonPoet If the first Q had asked, "What pressure would lead to a creature?" I'd have voted to close it as I did this Q. As it happens, it narrows the kind of condition it's looking for (evolutionary pressure, not just pressure) and gave a very specific condition the pressure was expected to produce (Ogres, defined with 14 characteristics... you don't identify the commodity and, unsurprisingly, gave no characteristics for it). Be specific. Otherwise, you're just brainstorming for your story and that's off-topic. $\endgroup$
    – JBH
    Mar 8, 2022 at 6:44
  • 1
    $\begingroup$ And if you're looking for both what to be dependent on and why that dependency exists, then your Q should be closed as Needs More Focus. You get one question.... $\endgroup$
    – JBH
    Mar 8, 2022 at 6:47

5 Answers 5



New books, music, films, etc. As for sending a mission and not merely transmitting: the transmitter power, selection of works, and last, but not least, bandwidth all speak against it.

Those traveller guys want to come to your planet, buy a lot of media suiting their own taste, and fly back.

In a sense it's a FUD, a mode / popularity thing. Nobody needs foreign music that is 200 years old. But it would be so cool to listen to it!

As for bandwidth: never underestimate the bandwidth of a truck, full of SD cards.

  • 1
    $\begingroup$ The ping is abysmal, though. $\endgroup$
    – Monty Wild
    Mar 8, 2022 at 4:17
  • $\begingroup$ This is Ancient Earth's most foolish program -- Why does Ross, the largest Friend, not simply eat the other five? $\endgroup$
    – Daron
    Mar 8, 2022 at 14:02
  • $\begingroup$ With instantaneous communication, which presumably includes all digital media, this makes no sense. It would have to be something physical to wait 200 years. $\endgroup$
    – StephenS
    Mar 8, 2022 at 18:30

Exotic Matter

The underlying assumption of this answer is that the other civilization is further along the Kardashev scale than humanity. If humanity isn't even at K1 and they are beyond K1, any manufacturing process requireing huge amounts of energy will be cheaper for them. Note that this also means that interstellar propulsion is easier for them, if they use Kare Sail Beams or Laser Coupled Particle Beam Beam-Riders. Humanity can just use kinetic mines in the Oort for deceleration.

Given that they might have a few orders of magnitude more energy, they can produce a lot of interesting and useful stuff:

  • antimatter (maybe even the non-explody kind made from the other 4 types of quarks)(you mentioned no fusion tech in your world, that makes little sense, as amat catalised fusion and termonuclear Orion drives seem pretty viable)
  • exotic isotopes (stable ones that aren't common, radioactive ones that are valuable dispute their decay, exotic super dense ones (see island of stability))
  • magnetic monopoles
  • metastable neutronium
  • strange matter
  • structural perfect materials (think Graphene, nano tubes and other stuff where even small imperfections are annoying)

Everything there can be made in Sol, but we don't have the industrial scale (read circumstellar particle accelerators) facilities, just scientific ones. Thus, as soon as the energy cost of production exceeds the cost of transportation by a large enough margin, you are golden. Trade might even be profitable before that, as their facilities would run dry otherwise.

  • $\begingroup$ I was thinking of something like this but perhaps a compound we can't make. Assume you need to put A and B and C together a certain way and it isn't thermodynamically possible. But, you CAN put A+B+ D together, and D happens to be radioactive. Over time, D decays and turns into C, so you magically made A+B+C compound. It requires enrichment technology we can't do for whatever reason. Again my world has our own technological limits. $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 17:40
  • $\begingroup$ "No fusion" simply means we can't use it practically for stable reactors. Fusion obviously exists. But "structural perfect materials" is a very logical answer. $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 17:43
  • $\begingroup$ @VogonPoet But we do have energetically viable reactor designs. Google Project Pacer. If cheaper (or simply pure fusion bombs, which are theoretically already possible) are available, this is perfectly viable. The big issues of Project Pacer are economics and politics. The engineering is a sound, for a 2GW fusion reactor. $\endgroup$ Mar 8, 2022 at 21:15
  • $\begingroup$ my ships don’t have salt caves on them yet, we still use stone age metal and carbon textiles. ;) $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 22:24
  • $\begingroup$ @VogonPoet Well, that is a certainly a big issue that needs to be fixed. xD However, the high-tec version of that is a mag-orions magnetohydrodynamic generator. Plasma moving through a magnetic field can be used to produce electricity. $\endgroup$ Mar 9, 2022 at 12:10

Rare Earth Metals

As their name predicts, these elements are rare here on Earth. But they are also used in practically all of our modern technology. Within the next few decades, Earth with run though its entire reserve of several of these metals significantly hampering the quality of our electronics, magnets, optical equipment, etc. Here is a list of just some of the things we use these elements for that will be much harder to do in a few decades without them.

  • Neodymium is used to make powerful magnets which will be a vital component in your anti-matter containment systems.
  • Lanthanum is used in high-end lenses and lighting.
  • Cerium is used in various petrochemical processes.
  • Praseodymium is used in high stress steel alloys like jet engine parts.
  • Gadolinium is used for making X-Ray and MRI machines.
  • Yttrium, Terbium, Europium, and Gadolinium are used in TV screens.
  • Europium is also used in Nuclear control rods.

The possible future demand for these rare elements is so high that once we run though our Earth based reserve, we will need to switch to mining our local solar system, but even that will eventually run low and we will need to import them from other less developed solarsystems.

  • $\begingroup$ This snuck in just under the wire. Good call. $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 22:47

If you're playing remotely fair with the energy costs of interstellar shipping the cost per pound will be astronomical. Anything that can be made locally will be--and note that that includes even things like gold. We know how to make gold, it's just not worth doing so. It's a lot easier to make gold than to ship it to the stars, though.

Thus your product must be impossible to make locally. Fundamentally, that comes down to information. Either directly as Oleg Lobachev's answer does or indirectly in the form of some product we don't know how to make an the aliens are keeping the production process secret. If you take the latter approach, though, you end up with the problem of what the aliens want in return. If their tech is that far beyond ours what do we have worth shipping to them? Nothing.

In a universe where you can't cheat Einstein trade will consist entirely of messages beamed to other planets, not physical goods. Starships will exist to bootstrap a base in a new star system and possibly to ship people around (I expect upload to kill off the reason to send people, likely before we reach the point of sending people in the first place.)

If you want interstellar trade in products you have to handwave something pretty major in terms of interstellar shipping costs.

  • $\begingroup$ My fictional world does not have bioengineering, so I believe any biological byproduct would also be impossible to replicate. This is especially true since nothing better than a microbe could be shipped intact, and we each would have to choose to send this secret little bug. Proteins, medicines, synthetic materials that can only be made biologically come to mind. A simple example is the conch shell. We cannot replicate the lattice in their tough inner shell. $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 5:07
  • 1
    $\begingroup$ I would temper down the 'impossible to make' to a mere 'nearly impossible' - at least one of the two civilizations is able to effect thrice-yearly interestellar travel at 0.1c. That is immensely impressive, but not god-mode. There is still an economy, so there are things worth more than other things, including a 200a 0.1c container shipment. $\endgroup$
    – bukwyrm
    Mar 8, 2022 at 9:38
  • $\begingroup$ I think you have also answered the Fermi Paradox. $\endgroup$
    – user81881
    Mar 8, 2022 at 16:28
  • 1
    $\begingroup$ This answer & the one by @Oleg_Lobachev reminds me of the Hitchhiker's Guide to the Galaxy and the endeavor to find the answer to the ultimate question - information. A super computer, Deep Thought, is made to find the answer, but after 7.5 million years it comes up with "42". A better computer is then devised - the Earth. Just before readout the Vogon's destroy Earth to make an intergalactic by-pass, or something similar. Are you taking note of this Vogon Poet? :-) $\endgroup$
    – user81881
    Mar 8, 2022 at 16:40
  • $\begingroup$ @bukwyrm 1kg at .1c requires 9E+14 J with a perfect drive and nothing but payload. At local power prices that's nearly $3 million. I would be amazed if the real cost wasn't many times that. $\endgroup$ Mar 9, 2022 at 3:04


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Water is a necessary commodity because people are made of water [citation needed].

$\Large \color{green} \checkmark $ required for human society to continue it's standard of living

$\Large \color{green} \checkmark $ required for the continued health of humanity

$\Large \color{green} \checkmark $ required for the economic health of human society

Your human society is on a planet with no natural water source. That is okay for the moment because they brought some water when they got here. They live in domes and recycle their sweat and pee and poo water and drink it over and over again.

The problem is the water will not last forever. Maybe the population is growing too quickly? Maybe the recycling system is only 99.986% efficient? Maybe all their technology is steampunk and needs to HISSS a cloud of steam into the atmosphere every now and then so the punks don't forget about the steam.

In any case the colonists predict the water will run out in 300 years. So they order an ocean's worth of water from the aliens.

But water is heavy [citation needed] and space is big. So the water will take centuries to arrive.

Bonus: If we are talking about your super hot steampunk world then it makes sense that water is hard to come by on such a planet. Perhaps the colonists expected to find water underground or on the ice-caps once they arrived but were disappointed and had to start recycling.

  • $\begingroup$ Oh I am sorry this is "our human society" on earth... It's a good answer for sure but I have to explain how we don't have water on earth :p You have accidentally answered a different question in a different story however. $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 15:35
  • 1
    $\begingroup$ Water is some of the most abundant stuff in the universe. There will be icy commets on the edge of their solar system. They can get oxygen from their rocky planet, and combine it with hydrogen taken from their star. $\endgroup$ Mar 8, 2022 at 16:23
  • $\begingroup$ @DonaldHobson Getting hydrogen out of a star sounds like an awful lot of work. $\endgroup$
    – Daron
    Mar 8, 2022 at 16:49
  • $\begingroup$ @Daron Firstly the sun throws off quite a lot of solar wind. Like over a million tonnes per second. That's enough to make a lot of water, and it can be gathered by a big magnet. Easyish compared to 10% lightspeed. $\endgroup$ Mar 8, 2022 at 16:53
  • $\begingroup$ It's not an entirely bad answer. Pollution can make imported water necessary. The challenge here is as the comments say, water can be found locally. An interplanetary agreement makes sense here, but maybe not an interstellar one. $\endgroup$
    – Vogon Poet
    Mar 8, 2022 at 17:36

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