The Theory of Interstellar Trade

I did not think that Paul Krugman was still writing academic papers. Nor have I seen any evidence in the last decade that he still has any sense of humor.

Consequently, I was surprised to see an article written by him entitled “The Theory of Interstellar Trade,” published recently in the journal Economic Inquiry. Here is the abstract of the paper:

This article extends interplanetary trade theory to an interstellar setting. It is chiefly concerned with the following question: how should interest charges on goods in transit be computed when the goods travel at close to the speed of light? This is a problem because the time taken in transit will appear less to an observer traveling with the goods than to a stationary observer. A solution is derived from economic theory, and two useless but true theorems are proved.

A quick look at the acknowledgments, however, clears things up. The original manuscript was written in July 1978, when Krugman was an active researcher and being a curmudgeon wasn’t part of his professional identity.


Have you ever read his blog?

Even if you don't want to read the actual posts, simply read the headlines. They are hilarious (as are the captions to the images).

A lack of a sense of humor is certainly not one of his deficiencies (unless your sense of humor starts and ends with kicks in private parts).


It is clear you have not read Krugman's blog. So why the sniping?

Eric M. Jones

A Fast Fast Rocket to a Far Far Place....

Maybe there is a simple solution to the Fermi Paradox: "Where are the aliens?"

We think of the possibility of journeying to another star as something that could be done with current technology. I would be a very long trip....

In about 1963, a Westinghouse scientist we knew, explained to me that if such a voyage were to happen, extraordinary measure would have to be taken to conserve materials. For example when light bulbs burned out would have to be disassembled and the tungsten filaments and tungsten dust would have to be salvaged, reformed and reused.

I looked upon this as a good example of the hardships and engineering challenges that would crop up when planning such a voyage. "Imagine having to disassemble light bulbs to reuse the filaments," I thought.

Now I sit here in 2010 and imagine the brave spacemen who never left in 1963 and would be grateful they do not have to cope with a spaceship filled with glowing lamp filaments, vacuum tubes, racks of crude transistors, no LEDs, (only Nixie tubes and vacuum tube VDTs for digital displays!) no computers, no integrated circuits, no pocket calculators, no microfilters or reverse osmosis in the sewage recycling system; their rank cabins filled with 33 1/3 vinyl records, and reel-to-reel tapes. Wind-up wristwatches, crumbling paperback books and 8-mm films for entertainment....and no great velocity to shorten the miserable journey either.

The best course of action--a few years after leaving---would be to cancel the whole damned trip and return home.

The logical quandary is that at any time in the foreseeable future, technological growth would out-pace our current technological ability so that crossing the great void would make no sense. At anytime in the foreseeable future this would only get worse.

It has been pointed out that if you went to the stars you would find humans, who left much later there to greet you. And YOUR trade goods would be antiques. They in turn had found humans who left even later, there to greet them, who in turn....etc. The first guy to leave Earth for Alpha Centuri would be greeted by the guys who left the week before he arrived at Alpha Centuri. What kept you?...and no we don't want any of that ancient crap you're hauling.

We might as well stay home.



Typical criticism of Krugman... we can't prove he's wrong, so we'll just deride him as a shrill, humorless crank. Rajan provided a long defense of his book and why he disagreed with Krugman.


I really have to agree with addicted there. Paul Krugman is hilarious.

The Difference

Between being funny and being sardonic can be difficult to detect, but Krugman is most certainly beyond the sarcasm that can be funny and into the cynicism that is not.

David Chowes, New York City

Easy! A flat fee: 1 Cosmo.

David Chowes, New York City

Or, 10 Cosmos for first light year, and...
1 Cosmo for each additional light year, and...
1/2 Cosmo for each nanosecond for any interuption(s).

A sophisticate meter would be measured... Similar to the ones found in taxis.


Listen to any of Krugman's talks and you'll hear good examples of humor. Not always successfully funny, of course, but we all can't be commedians. And as a poster above mentioned, his blog does have great little jokes.

I didn't realize he was truly funny until I was playing a speech by him on my speakers while cleaning the house, and my girlfriend started laughing at Krugman's jokes. Apparently he does a decent job at humor, even if he seems so glum and serious moreso these days.


Its a good read, but it only takes to the special relativistic case. General relativistic interstellar economics (gosh, I sound smart now) would be a fun update to his older paper. Oh, the possibilities that time relativism brings! Faster production clocks, slower durable goods clocks, compounding interest at lightspeed, a wonky nerdy dream.

Drill-Baby-Drill Drill Team

The good news is astronomers found a planet at the right distance to a star that would allow optimal surface temperature, liquid water and non-toxic gas that would potentially support life.
But before realtors start hanging their signs, there is the bad news:
If you could build a car that can drive at the speed of light, 186,000 miles per second, then it will take you 20 years to reach it. Current land speed record at Bonneville is about 760 miles per hour.

I assume a space craft will go fast,(let say 10, 000 mph, the speed of an ICBM missile) but nowhere near the speed of light. Chances are you will die from old age in transit, and must reproduce a baby, educate and train that child, and make his/her life mission the trip you began before said child was born. And that child may not reach the destination and must also breed, and so forth and so forth.

And you must forbid the two year child from asking "Are we There Yet! @^%@%^**^@!"

Interstellar trade will not be viable, if trade distances are generational. We might be lucky just to send light encoded Morse-code messages. Better to invest NASA's budget in better Hollywood Sci Fi movies. Captain Kirk and the Queen of the Cat People. Rarrrar



Why the cheap shot at Krugman?

I'd rather be a curmudgeon that uses his column on the NYT to address and offer alternatives to current economic policy (however disagreeable) than an economist who uses his blog to take potshots at other academics.

If you have problems with his point of view or his methods, perhaps you should address those rather than Krugman's identity.


Krugman may be a curmudgeon but I find him to be a funny curmudgeon. I like his sense of humor (both in his talks and print...).


Hmm, no evidence for a sense of humor? Maybe actually reading a few posts from Krugman's blog would have been a good start.

Is "curmudgeon" supposed to be dismissive? I look to Krugman to provide some sensible economic analysis in an area increasing dominated by commentators prescribing austerity and sacrifice by the poor, and tax cuts and incentives to the rich.

Howard Mahler

An unnecessary and inaccurate attack on your fellow economist.
Rather than disagree with something he said, and explain why you disagree, you took a few cheap shots.
It is your blog, so you can write what you want within any legal limitations, but you should be ashamed of yourself.


Dear "addicted" -
In the newspaper biz, the article writers do not write their own headlines nor photo captions. If you find humor there, it isn't Mr. Krugman's.


Truly sad. I love reading both blogs, have both of your books. You and Krugman are both highly interesting to read from different perspectives.

I guess his poor review of Rajan's book REALLY got under your skin. First Rajan gets a column to grouse about, and now you are launching ad hominems.

Just go back to what you do best, shedding light on the interesting but overlooked phenomena that effect us.


I'm a daily reader of the blog.... Never before commented, but the paper is hilarious.... What about de '87 paper? Can't wait to read that !!!!!

David Chowes, New York City

[Re: #s7, 8]

Also a surcharge of 1 Cosmo during Monday through Fridays, GMT. And no service on religious holidays -- except in an emergency (as defined by the given religion).
Though athiests and agnostic would be exempt.


Dear "Jake" @16:

In the blog biz, they do. Research may be hard but, here, it's all of two clicks away.