In the wake of Hurricane Katrina, much of New Orleans is under water in the top satellite image, taken on August 30, 2005, at 11:45 a.m. CDT by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Early news reports say that as much as 80 percent of the city is flooded after levies failed to hold Katrina’s massive storm surge back. The flooding is getting worse as water slowly seeps into the city from Lake Pontchartrain. On Saturday, August 27, 2005, New Orleans formed a tan and green grid sandwiched between the lake shore and the river in...