The stuff we do late in this century, assumiming prosparity continues, depends on break thoughs we make the next decade or two. Will we mass produce CNT = carbon nano tubes or something even stronger? Will we mass produce room temperature super conductors? Will we have practical space elevators, fusion, SSP = space solar power? Gigawatt (average power) lasers?
If the world ecconomy is bad the last half of this century we may make little progress after 2050. Neil