The Planet Money discussion was a good teaser: http://www.npr.org/2014/05/02/309040279/in-4-000-years-one-thing-hasnt-changed-it-takes-time-to-buy-light http:/

The Planet Money discussion was a good teaser: http://www.npr.org/2014/05/02/309040279/in-4-000-years-one-thing-hasnt-changed-it-takes-time-to-buy-light http://www.npr.org/2014/05/02/309040279/in-4-000-years-one-t...