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.
2019 September 16
Explanation: What are those colourful rings around the Moon? A corona. Rings like this will sometimes appear when the Moon is seen through thin clouds. The effect 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. The featured lunar corona was captured around full Moon above Turin, Italy in 2014. Similar coronae that form around the Sun are usually harder to see because of the Sun's great brightness.
Authors & editors:
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
A service of: ASD at NASA / GSFC
& Michigan Tech. U.