James Rogers writes:
> (population 50) is 25 miles away. Talk about under-utilization...
And we're not even talking nano here. A nigh-perfectly recycling environment capable of sustaining (and entertaining!) a human won't take too many square meters of photosynthetic panel surface. And this is still planetary-surface based thinking. All the thousands km of rock below the patch of real estate reaching down to the Earth core, only to keep the topsoil and the atmosphere from flying off into space do not appear particularly efficiently utilized.
And don't get me started on circumstellar Dyson clouds of computronium. LOTS of unreal estate there.