Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2023 March 8
A flattened map of the Earth is shown illuminated only by
how bright the night sky is.
Please see the explanation for more detailed information.

Artificial Night Sky Brightness
Image Credit: Data: JPSS Satellites; Processing: David J. Lorenz

Explanation: Where have all the dim stars gone? 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 stars are visible. The featured map indicates the relative amount of light pollution that occurs 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 little amounts of light pollution.

Light Up Your Internal Night Sky: Random APOD Generator
Tomorrow's picture: planetary defense


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