Have you ever seen all the earth and its cities and major population centers at night? Probably not. This is an incredible picture taken by NASA satellite. You will have to scroll to see this one. It's large, so be patient as it downloads - but it is very interesting and beautiful! (This is what aliens see when they visit earth at night). For those of you who are technical - this has been put together as a single picture as the earth of course is not in darkness everywhere at once. Go here for smaller picture.