The world is not enough 2016-10-01 Economist, Mars, Elon Musk, Erythraean Sea Bubble, changeist Is this the beginning of a new ‘Mars debt’ industry? via http://www.economist.com/news/science-and-technology/21707915-elon-musk-envisages-human-colony-mars-he-will-have-his-work-cut-out