Message #241443

[Theodorich]

Green Lantern

Photograph by Thilo Bubek

Bright green auroras light up the night sky in a picture taken near Tromsø, Norway, on January 21.

The colors of auroras depend on the types of gases in Earth's atmosphere being affected by a solar storm. In most cases, auroral lights come from oxygen being "excited"—given extra electrical energy—during the collisions of gas atoms with solar particles. The charged-up oxygen releases the extra energy as green light.

(Also see "Photos: Multicolored Auroras Sparked by Double Sun Blast" [August 2011].)

Published January 25, 2012