AstronomyPicture of the Day—20181120

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.

2018 November 20

CreatureAurora Over Norway

ImageCredit & Copyright: Ole C. Salomonsen (Arctic Light Photo)

Explanation:It was Halloween and the sky looked like a creature. Exactly which creature,the astrophotographer was unsure but (possibly you can suggest one). Exactlywhat caused this eerie apparition in 2013 was sure: one of the best auroraldisplays in recent years. This spectacular aurora had an unusually high degreeof detail. Pictured here, the vivid green and purple auroral colors are causedby high atmospheric oxygen and nitrogen reacting to a burst of incomingelectrons. Birch trees in Tromsø, Norway formed an also eerie foreground.Recently, new photogenic auroras have accompanied new geomagnetic storms.