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 <i>ship</i> something (including ourselves) to another star system is based on very quaint notions of identity binding and what it takes to produce things.
Vaguely on topic - the novel A Deepness in the Sky by Vernor Vinge touches on this subject a fair bit.<p><i>potential spoilers follow</i><p>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)
>A solution is derived from economic theory, and two useless but true theorems are proved.<p>>This paper represents one small step for an economist in the direction of the theory of interstellar trade.<p>>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.<p>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!<p>>This paper, then, is a serious analysis of a ridiculous subject...
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.
> 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).
So riddle me this -- how did Adam Smith's work (published in 1776) influence the initial settlement of Virginia (1607) and Massachusetts (1620)?<p>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.
Interstellar travel will consist of information travelling at the speed of light. Pretty much nothing else is practical.<p>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.<p>Then information is sent to the factory, which proceeds to bootstrap a civilization.