On Thu, Jan 03, 2019 at 09:11:02PM -0500, Kurt Feltenberger wrote:
> as I was watching the videos I started to think about the immense
> amount of materials in one solar system and how all it takes is the
> ability to reach them to be able to recover them.

Pretty much.  Even without space travel, cheap energy opens up immense
opportunities for using and recycling resources that would otherwise
be uneconomical.  Nearly all of the "resource" shortages on Earth
today are really just disguised energy shortages.

> Then, since being able to build large space structures is doable,
> the next question was why don't they move to agricultural stations
> using hydro- and aeroponics?

The usual answer is cost.  It would almost certainly be cheaper,
safer, and more productive to build them on a planet's surface anyway,
at least up to the point where you run out of planetary surface.
Space structures will be expensive for more reasons than just the cost
of getting stuff there, especially if they have to reliably keep
things and people alive.

> Now, dragging this back to Traveller and trade, it comes back to my
> original question; just how much would be moved between systems?

This is going to depend very strongly upon cost.  If space transport
were free, then even a tiny difference in supply and demand would make
it worthwhile to ship huge amounts of goods and people.  The published
costs of freight compared with living costs in Traveller make it
comparable to surface transport on Earth today.  That is, cheaper to
ship tomatoes halfway around the world from Mexico to Australia than
to grow more tomatoes in Australia.

At these prices, imports and exports seem to be in the range 10-20% of
GDP for a large number of countries.  The costs of goods in Traveller
do not appear to be markedly lesser or greater as a proportion of
average incomes than in the real world, so it seems likely that a
similar percentage would hold there.

Of course, the real question hiding behind that is whether goods
should be cheaper.  My personal view is that the advanced technology
should make almost all of them radically cheaper, but then that might
depart too much from Traveller for many people.

- Tim