The Theory of Interstellar Trade

http://fermatslibrary.com/s/the-theory-of-interstellar-trade

by alokrai • 8 years ago

107 180 8 years ago

brudgers• 8 years ago

regular PDF, https://www.princeton.edu/~pkrugman/interstellar.pdf

azeotropic3• 8 years ago

So riddle me this -- how did Adam Smith's work (published in 1776) influence the initial settlement of Virginia (1607) and Massachusetts (1620)?

I'm guessing Krugman hadn't actually read Wealth of Nations, since anyone who had couldn't possibly have made this mistake. That's pretty shocking.

dnautics3• 8 years ago

Ansibles allow violating causality

azeotropic3• 8 years ago

I was waiting for him to go there -- if he had, I'd have been sure it was a joke.

Fomite• 8 years ago

Given the whole thing is tongue and cheek, one could read "Could this be as influential as Adam Smith's work on the initial settlement of Massachusetts and Virginia" be a tongue-in-cheek acknowledgement that this work is effectively pointless.

...you know, like the whole rest of the paper.

sulam2• 8 years ago

You’re suggesting that the winner of a Nobel Prize for Economics hasn’t read Adam Smith?

I’m guessing you’re wrong.

azeotropic3• 8 years ago

I doubt it. What fraction of Nobel Prize winning biologists do you believe have read Darwin?

georgecmu• 8 years ago

I'm guessing you parsed it wrong.

"Could this be as influential as Adam Smith's work on the initial settlement of Massachusetts and Virginia" refers to Adam Smith's work on the initial settlement of Massachusetts and Virginia, not to purported Adam Smith's work influence on the initial settlement of Massachusetts and Virginia.

mirimir14• 8 years ago

Right, "on" here means "about". English can be annoying.

lisper40• 8 years ago

Any civilization that has mastered interstellar travel will almost certainly also have mastered atomic transmutation as well. So as long as all the interesting stuff is made of atoms, and the atoms over there are the same as the ones over here (which AFAWCT they are), there are only two possible "goods" that could be worth transporting between star systems: information, and free (in the physical, not the economic sense) energy. You don't need a space ship to transfer either of those, you just convert them into photons and let Maxwell do the work. The idea that it might be worthwhile to actually ship something (including ourselves) to another star system is based on very quaint notions of identity binding and what it takes to produce things.

sixo• 8 years ago

will almost certainly also have mastered atomic transmutation as well

I don't see any reason to think that's true.

jack92• 8 years ago

Why not? We started atomic transmutation with fire.

lisper40• 8 years ago

Why not? If stars can do it, why not a sufficiently advanced civilization?

mlindner• 8 years ago

You don't think there would be any trade in antiques? Even in the modern world, just because we can reproduce something exactly doesn't mean there are many people willing to spend lots of money on something that is unreproducible.

sounds• 8 years ago

A lot of the value of antiques comes from the lost knowledge they represent, whether that's just sentimental "you just had to be there" experiences or more concrete "you don't know how to make the varnish on a Stradivarius" lost knowledge.

For that matter, the distances between systems creates a sort of time-travel effect. You receive their knowledge hundreds of years after the fact, making it implicitly "antique lost knowledge."

So I think the point still stands that all trade would be done using photons.

I would be very interested to discuss how "trade done using photons" is such a 21st-century concept and that it bears as much resemblance to interstellar trade as the black pepper trade of the 13th-century proscribes capital markets today.

lisper40• 8 years ago

Well, I hope that any civilization that masters interstellar travel would have moved beyond such foolishness. If you can produce an atom-by-atom duplicate, what does it even mean for something to be "the original"?

http://blog.rongarret.info/2015/02/31-flavors-of-ontology.ht...

kcanini• 8 years ago

AFAWKT

"As far as we KAN tell"?

lisper40• 8 years ago

I probably started out thinking "As Far As We Know" and then mentally veered at the last moment. Thanks. Fixed.

squirrelicus11• 8 years ago

Where I think you're wrong is that you seem to assume there's a path to arbitrary transmutation. It may not be possible, and I would argue, almost certainly isn't.

gibybo2• 8 years ago

Do you see some fundamental limit other than energy?

Robotbeat2• 8 years ago

I used to think that was true. But then I researched practical interstellar travel methods (not quite relativistic, 0.1c), and they seem doable from a physics and engineering perspective (if you controlled the world's wealth), but we have no real executable plan to build a transporter.

squirrelicus11• 8 years ago

Not to mention that transporters (disassembler/reassemblers) are (a) murder machines, and (b) cloning machines.

adrianN2• 8 years ago

We could probably build an interstellar probe if we redirected the world's defense spending into the project for a decade or so. Nuclear pulse propulsion looked viable fifty years ago and the projects were only stopped because of the test ban treaty. A ship powered by nukes can reach single digit percentages of the speed of light. That's enough to reach the nearest stars in one or two generations.

Johnny555• 8 years ago

It's very inexpensive to create nearly exact replicas of artwork, yet people are still willing to pay a lot of money for the original.

So maybe people will be willing to pay lots of money for hand-crafted alien artwork.

tomrod• 8 years ago

Perhaps that's the great filter before us: can we learn to appreciate sans ownership?

commieneko• 8 years ago

That is similar to the answer I came up with in high school, about 40 years ago.

Artwork, objects of note, curiosities with provenances, tourists, off the grid information that needs to remain _really_ secure, spies, traitors, patriots, displaced peoples, artefacts bound to a religious, gifts, bodies, deceased bodies, prenatal bodies, slaves, sex objects, objects of devotion, objects of derision, pariahs.

I actually wrote a short story about a trade empire that was built by a race of aliens (they looked like lizards) that had odd religious beliefs that required them to build monasteries all over the galaxy, and staff them with praying monks.

The monk's duties were very simple, each day they had to silently read from a small paper prayer, then burn the strip of paper over a candle. The rest of the day they partied, got drunk, had sex (monks could be of either gender), or wrote non-prayer literature.

Writing prayers was an unforgivable sin, the prayers had to come from the home planet. There was a huge fleet of trade ships created to deliver the paper prayer strips in bulk.

In return for the land for the monasteries, the alien lizards would give rides on their space fleet. They had single use vouchers that went from point to point, and they had travel passes which allowed general travel. Basically a bus pass for the galaxy. And since they had a monopoly on FTL ships, they delivered mail.

One day the prayer ships stopped coming. Everybody goes bananas. Nobody travels. Economies collapse.

Plus somebody has to feed the monks, and keep them entertained or else they go on party binges. Can't let them starve, because the ships might start coming again.

A generation later the ships start showing up again. No explanation given, and it's impolite to ask. The kind of impolite that gets you cut out of the prayer circuit.

That was all backstory, the actual story starts with an undercover agent from Earth getting sent to the lizard homeworld to try and find out WTF. He only has partial passage and a small consignment of trade goods. The backstory got backfilled as the agent wheeled and dealed his way towards the home world. I did have an ending, but I think I'll not spoil it in case I ever want to try and rewrite the story.

My 17 year old prose stank, unsurprisingly; even at that tender age I could smell it. Not sure I can do better now, but who knows.

dredmorbius• 8 years ago

Art with provenance from a dead artist is proof-of-work for an inflation-proof durable store of value.

(It remains subject to supply and demand -- the market for the particular work, artist, genre, or overall art market. But the piece itself is a one-off, and cannot be diluted.)

incadenza• 8 years ago

And human beings, and good luck convincing anybody to jump into one of those things...mostly because doing so is more or less dying.

nathanathan• 8 years ago

Cells might be worth transporting. Although the DNA can be sent as data and reconstructed, de novo reconstruction of the rest of the cellular machinery needed to run the DNA might not be practical.

antt2• 8 years ago

A seed universal constructor would be worth transporting. If that is a machine or a ship with cryogenically frozen human of all ages is a topic for another day.

credit_guy6• 8 years ago

Sending light across interstellar distances is not a trivial affair. No light source is perfectly collimated; per wikipedia [1] "The divergence of high-quality laser beams is commonly less than 1 milliradian, and can be much less for large-diameter beams". Not clear how "much less" is (and I couldn't find other sources), but let's say it's 2-3 more orders of magnitude. That would make it about 1 arc second (~5 microradians). The closest star is at a distance of about one parsec, which means that two photons starting here and having an angle of 1 arc second between them end up at a distance of 1 AU (astronomical unit ~ 150 MM km) between them. Assuming you can make an antenna the size of Jupiter at the target, for every photon that passes through that antenna you need to send 1 million photons. Every order of magnitude lower in the size of the antenna requires you to send two orders of magnitude more photons. In other words, an antenna 1% the size of Jupiter requires you to send 10 billion photons for each photon received.

You can get around that by setting up a system of relays, but you will end up needing lots of relays, and that's a complex infrastructure you need to maintain.

In any case, even after we master inter-stellar travel, don't think we'll have channels of communication of terabytes/second, every byte will be expensive to send across.

Sending information in the quantities needed to 3d-print stuff at atomic level will most likely be prohibitively expensive; remember 1 gram of hydrogen contains 10^23 atoms, while one terabyte only contains 10^12 bytes. If a little latency is acceptable, it will always be many times cheaper to just send the stuff you need rather than the information to 3d-print it at atomic level.

[1] https://en.wikipedia.org/wiki/Collimated_light

lisper40• 8 years ago

Sending light across interstellar distances is not a trivial affair.

I never said it was. But it's a hell of a lot easier (to say nothing of faster and more efficient) than sending matter.

cinquemb2• 8 years ago

The idea that it might be worthwhile to actually ship something (including ourselves) to another star system is based on very quaint notions of identity binding and what it takes to produce things.

I often think that the forms we take on now aren't suited for space travel (unless you consider living on a planet that is in motion through space as space travel) much less staying in low earth orbit for a year. We have to bend backwards to engineer materials to shield our presently fragile bodies, imo quite futilely, from the harshness of space. I think we'd be much better off modifying our bodies (or even rethinking what constitutes a body/form) to be able to withstand this harshness, at least in the interim before we can build a system that can somehow propagate energy FTL, though I definitely think we should pursue the latter, as the benefits could be realized on earth.

hackeraccount• 8 years ago

You're probably right but arguably sending traditional sense goods is in a certain sense sending information and energy i a single package. With enough density it might make more sense to ship the good then the energy and information used to create it.

dalore• 8 years ago

Some people would value getting an original whatever item and would pay a premium for shipping, rather then just getting it replicated. Extremely wealthy people would show off all the original non replicated items they posses from far away civilizations.

lisper40• 8 years ago

That is only true because we don't yet have the technology for making atomically perfect copies of physical objects. No one pays a premium for "the original" of a digital image.

imh• 8 years ago

A solution is derived from economic theory, and two useless but true theorems are proved.
This paper represents one small step for an economist in the direction of the theory of interstellar trade.
These complications make the theory of interstellar trade appear at first quite alien to our usual trade models; presumably it seems equally human to alien trade theorists.

This is wonderful and hilarious and full of cheeky fun (so so much more than I've quoted). It's perfect for the sigbovik crowd. Thanks for posting!

This paper, then, is a serious analysis of a ridiculous subject...

skookumchuck• 8 years ago

Interstellar travel will consist of information travelling at the speed of light. Pretty much nothing else is practical.

The real problem is bootstrapping it. Because weight is so incredibly expensive to send interstellar, the only thing that could work is sending a nanorobot with an ability to self-replicate and build a receiver and a factory once it arrives.

Then information is sent to the factory, which proceeds to bootstrap a civilization.

stephengillie2• 8 years ago

How would the economics change if we could only communicate at light speed, but had a functional Alcubierre drive (or other lightspeed technology) and could travel at FTL speeds?

tCfD2• 8 years ago

Presumably you would just load up the your Alcubierre station wagon with a bunch of backup tapes and send it down the interstellar highway. You could restore your backups before the original data is written!

sethrin3• 8 years ago

Do you consider FTL plausible? If so, why?

jakecrouch• 8 years ago

Interstellar travel will consist of information travelling at the speed of light. Pretty much nothing else is practical.

What's your reasoning for this? You would only have to accelerate at 1g for 3 years to hit 99.5% of the speed of light. You can use an electromagnetic shield for dust. It seems conceivable that this will be possible eventually, even if warp drives are not possible.

analog31• 8 years ago

Indeed, and the benefit of traveling at 0.995 c is that a container of information doesn't suffer from degradation by the inverse square law as it travels over a large distance. It might actually cost less energy to transport information to far flung destinations that way, interstellar snail mail if you will. Some amount of information has to accompany the robot anyway, at the very least, its initial operating instructions.

Of course whoever can get there at 0.996 c can take advantage of a market arbitrage. ;-)

seppel2• 8 years ago

1kg matter at 0.1c has a kinetic energy of 4.5x10^14 J

It is certainly very expensive to spend this amount of energy. But is it also extremely challenging to even extract this out of an engine that has to accelerate itself.

1kg matter at 0.995c has a kinetic energy of 8x10^17 J

This is the amount of enery you get if you convert 9kg in pure enery. That seems impossible to reach, even with an anti matter drive.

squirrelicus11• 8 years ago

Forgiving the problem of time dilation and the consequences it has on the expectations of conscious things...

You can't just accelerate 1g for 3 years. What are you burning? A chemical rocket can easily achieve 1g. For about 5 minutes. A nuclear rocket is great, you can get 1g easy enough, but you're shoving hot hydrogen out the back end to get that thrust.

The Rocket Equation teaches us that to get arbitrarily close to c, you need an exponential amount of your ship's mass to be propellant.

I recommend this website to everyone in this thread that hasn't read it yet

http://www.projectrho.com/public_html/rocket/

Edit: moreover, the problem of an EM deflector, or any kind of deflector, is that no matter what, no matter what, you must deal with the kinetic energy of the thing that just hit your deflector. It will (a) slow your ship down, and (b) cost you more energy, e.g. from your generator, to deflect it than it imparted on your vehicle. The energy numbers here are staggering. We have trouble theorizing how a relatively uncontrolled terawatt rocket might work, but imagine a terawatt reactor on your ship somehow powering a terawatt EMfield in front on your ship.

And then you have to worry about dust that's not charged and thus goes right through EM fields.

mirimir14• 8 years ago

Makes sense to me.

And even better, if you can exploit something at the destination to build your stuff. As in Carl Sagan's Contact and Peter Watts' Echopraxia.

pseingatl• 8 years ago

From the point of political economics, charging interest is not necessarily a given. Economies exist where interest is prohibited.

gibybo2• 8 years ago

In name perhaps, but the concept of an economic good having potentially different values at different times is universal. An economic system that tries to pretend it doesn't exist may work in the sense that a mathematical system without a 0 works. We can still analyze the system using the concept and develop insights using it as a tool, even if they don't recognize it themselves.

SECProto• 8 years ago

Vaguely on topic - the novel A Deepness in the Sky by Vernor Vinge touches on this subject a fair bit.

potential spoilers follow

Essentially, no spacefaring civilization is stable over long time scales, a culture (the Qeng Ho) get by through predicting which planetary system will have the economy to support refueling an interstellar craft (in the centuries-later future when they arrive). Trade advanced/secret technology development info for said refueling. The story has way more to it, but I loved it as a known-physics-following scifi story. I expect the audience of this site would also love it (and probably, many have already read it)

hartror• 8 years ago

Loose prequel to my favourite book of all time A Fire Upon the Deep. Vinge is a brilliant author with a background in maths and computing and it shows in his writing.

_audakel• 8 years ago

Thanks for the recommendation, I just got it on Audible and I'm looking forward to listening to it.

girvo2• 8 years ago

Software archeology! I adored that book. Highly recommended to anyone on HN that hasn’t read it, it’s well worth it. Quite enjoyable too, outside the neat hard sci-fi and cute extrapolations of modern day software engineering.

matt-snider• 8 years ago

Love this book. The prologue is one of my favourite beginnings to a book and hints at how epic/vast the book's universe is:

The manhunt extended across more than one hundred light-years and eight centuries. It had always been a secret search, unacknowledged even among some of the participants. In the early years, it had simply been encrypted queries hidden in radio broadcasts. Decades and centuries passed. There were clues, interviews with The Man's fellow-travelers, pointers in a half-dozen contradictory directions: The Man was alone now and heading still farther away; The Man had died before the search ever began; The Man had a war fleet and was coming back upon them. With time, there was some consistency to the most credible stories. The evidence was solid enough that certain ships changed schedules and burned decades of time to look for more clues. Fortunes were lost because of the detours and delays, but the losses were to a few of the largest trading Families, and went unacknowledged. They were rich enough, and this search was important enough that it scarcely mattered. For the search had narrowed: the man was traveling alone, a vague blur of multiple identities, a chain of one-shot jobs on minor trading vessels, but always moving back and back into this end of Human Space. The hunt narrowed from a hundred light-years, to fifty, to twenty - and a half-dozen star systems. And finally, the manhunt came down to a single world at the coreward end of Human Space.

ddingus8• 8 years ago

I am going to read that book.

Thanks for posting that excerpt. It is a near perfect, "and then ehat happened?" Hook!

mannykannot• 8 years ago

One of Larry Niven's 'Draco Tavern' short stories has the economics of interstellar traveling sales-aliens as its plot device. I don't recall the name.

gsanghera• 8 years ago

The ship's velocity can then be represented by a rotation of the axes; the rotation of the time axis is shown in Figure II. (Readers who find Figure II puzzling should recall that a diagram of an imaginary axis must, of course, itself be imaginary).

gangstead• 8 years ago

I've read this before but this is the first time I noticed that Krugman wrote the paper in 1978 and the references include a paper about faster-than-light travel written by him, published 1987.

godelmachine• 8 years ago

I read the Wikipedia article on this paper today and turns out Krugman wrote this when he was feeling quite low being embroiled in the rat race.

The Theory of Interstellar Trade

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