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 March 14
Explanation: It appeared, momentarily, like a 50-km tall banded flag. In mid-March of 2015, an energetic Coronal Mass Ejection directed toward a clear magnetic channel to Earth led to one of the more intense geomagnetic storms of recent years. A visual result was wide spread aurorae being seen over many countries near Earth's magnetic poles. Captured over Kiruna, Sweden, the image features an unusually straight auroral curtain with the green colour emitted low in the Earth's atmosphere, and red many kilometres higher up. It is unclear where the rare purple aurora originates, but it might involve an unusual blue aurora at an even lower altitude than the green, seen superposed with a much higher red. Now past Solar Minimum, colourful nights of aurorae over Earth are likely to increase.
Authors & editors:
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
A service of: ASD at NASA / GSFC
& Michigan Tech. U.