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.
2021 January 19
Explanation: Why does a cloudy moon sometimes appear colourful? 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 colours has different wavelengths, each colour diffracts differently. Lunar Coronae are one of the few quantum mechanical colour effects that can be easily seen with the unaided eye. Solar coronae are also sometimes evident. The featured composite image was captured a few days before the close Great Conjunction between Saturn and Jupiter last month. In the foreground, the Italian village of Pieve di Cadore is visible in front of the Sfornioi Mountains.
Authors & editors:
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
A service of: ASD at NASA / GSFC
& Michigan Tech. U.