I want to share another fascinating Economic study with you... this one from Brown University. The three authors, J. Vernon Henderson, Adam Storeygard and David Weil, were looking for a way to track economic growth in regions which have poor geographic connections, poor statistics, or have other impediments to useful growth tracking. Using light (specifically, light coverage in satellite photos) as a proxy for economic activity ("Consumption of nearly all goods in the evening requires lights", they state), they show the growth in productivity in remote regions using nighttime satellite pictures.