The Great Circle

Son John is on his way to China (should be arriving any minute now after a thirty-hour journey). His route as drawn by the Great Circle Mapper shows what we miss looking at the familiar Mercator Projection world map -- if you distort the scale on the axes, the shortest distance between two points (here, between Detroit and Tokyo) is not a straight line at all. You can try it with a globe and a piece of string if you don't get it.