A lot of information is shown in this image of Earth’s city lights. Although there is a map underlying the lights, why is it possible to see the outlines of the continents in many locations anyway? What does this tell about where cities are located? What geographical features can you locate? Can you find the Nile River? The Himalaya Mountains? The Sahara Desert?

What characteristics do the regions with the brightest lights share? What is different about them? How do they differ from the regions that are dark? What characteristics do those dark regions share and what is different about them?

The regions with the brightest lights are the most urbanized. Do they have the largest populations? Do they have the largest population densities? The brightest lights are found in the eastern half of the United States, Europe, and Japan. But the nations with the highest populations are China and India and the highest population densities are in some tiny countries such as Bangladesh, Taiwan, South Korea, and parts of Africa.

Can you locate your town?

^{Courtesy of Craig Mayhew and Robert Simmon, NASA GSFC. earthobservatory.nasa.gov/IOTD/view.php?id=896. Public Domain.}