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.

2024 May 30
The famous Eiffel Tower in Paris, France is pictured 
on the left lit up in gold at night. A blue laser shines
out from the top. Clouds dot the background sky. The Moon
is also visible through the clouds, but is circled by 
colorful rings: a lunar corona.
Please see the explanation for more detailed information.

A Lunar Corona over Paris
Image Credit & Copyright: Valter Binotto

Explanation: Why does a cloudy moon sometimes appear colorful? The effect, called a lunar corona, is created by the quantum mechanical diffraction of light around individual, similarly-sized water droplets in an intervening but mostly-transparent cloud. Since light of different colors has different wavelengths, each color diffracts differently. Lunar coronae are one of the few quantum mechanical color effects that can be easily seen with the unaided eye. Solar coronae are also sometimes evident. The featured image was taken last month from Paris, France. The blue beacon emanating from the Eiffel Tower did not affect the colorful lunar corona.

Portal Universe: Random APOD Generator
Tomorrow's picture: nebulous realm

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