http://www.projectrho.com/public_html/rocket/macguffinite.ph...
Personally I imagine we're better off when we share information for free, but I haven't tested the hypothesis.
And here I am thinking I was being insightful.
Fissionable materials might be valuable to planets that have none of their own and want to make use of nuclear power.
People are a resource of their own that may be wanted on sparsely inhabited planets (especially if birth rates on technically advanced planets are similar to those in developed nations here on Earth).
Apart from information which has been mentioned twice I'd say habitable and highly hospitable land (Earth-like planets) as well as access through or even ownership of territory. Space might be big but if we're limited by the speed of light then these things have immense value and still considerable value if we're somehow able to get around it.
Though even that, it seems it'd be cheaper to transport the people to the energy than vice versa.
Beyond a certain point of post-scarcity, everything stops being scarce, including invention and innovation.
We're already at that point with artefacts like music. Aliens could turn up tomorrow with centuries of unique music, and after the initial decade or five of novelty the music would end up as yet another playlist on Spotify, among countless others - so many no individual human could ever listen to more than a tiny fraction of them.
That's a rather silly example, but the point is still valid: if you imagine the same trend occurring in physics, biology, and technology, you end up at a place only a few centuries from so much novelty and invention is being produced that it's no longer a scare commodity. External sources might add a few minor tweaks to the generation system, but when even game changer technology stops being scarce, what is there left to trade?
Right but wouldn't you need interstellar trade to reach this milestone of post-scarcity? Otherwise you'd have to assume all forms of invention are achievable with the resources you start with.
Wouldn't game theory make you want to limit the resources and capabilities of your neighbor in case they try to do the same thing to you? So this idea of post-scarcity is never met because the uncertainties of attack from any number of other space-faring civilizations requires that you invest a significant chunk of your resources into your military. You could also have internal turmoil - the human race splits into distinct civilizations with different political, social and technological goals.
It's funny you say music I've always thought every pop song has been made but then someone makes a new song that everyone loves.
Even if there's some alien truffle delicacy that only grows in the shade of a tree bathed in UV light from an alien star, surely that could be cultivated here in an artificial habitat far easier than shipping it light years across the galaxy?