Night Sky Brightness
From many places on the Earth including major cities, the night sky has been reduced from a fascinating display of thousands of stars to a diffuse glow through which only a few are visible.
The featured map indicates the relative amount of light pollution across the Earth. The cause of the pollution is artificial light reflecting off molecules and aerosols in the atmosphere.
Parts of the Eastern United States and Western Europe colored red, for example, have an artificial night sky glow over ten times that of the natural sky. In any area marked orange or red, the central band of our Milky Way Galaxy is no longer visible. The International Dark Sky Association suggests common types of fixtures that provide relatively small amounts of light pollution.
Image Credit: Data: JPSS Satellites; Processing: David J. Lorenz
source APOD
