Light pollution occurs during the night when artificial light from towns and cities beams upward into the sky. The light reflects off the moisture, air pollution, and dust that are in the air. This reflected light pollutes the night sky and blots out the view of the stars. It is believed that about half of the people in the United States can barely see the stars at night anymore.

Visit one of the Web sites below to see what light from the United States looks like from outer space. Then return to this page.

     Light Pollution Picture