APOD
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.
Nacreous Clouds over Sweden
Explanation: Vivid and lustrous, wafting iridescent waves of color filled this mountain and skyscape near Tanndalen, Sweden on January 3. Known as nacreous clouds or mother-of-pearl clouds, they are rare. This northern winter season they have been making unforgettable appearances at high latitudes, though. A type of polar stratospheric cloud , they form when unusually cold temperatures in the usually cloudless lower stratosphere form ice crystals. Still sunlit at altitudes of around 15 to 25 kilometers the clouds can diffract sunlight after sunset and before the dawn.
| Date | January 10, 2020 |
|---|---|
| Credit | Image Credit & Copyright: P-M Hedén ( Clear Skies , TWAN ) |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |