Blue Flame, Colour photograph (Giclée) by Shane Lamb. Alaskan night sky is dark from August to April. The Aurora is a natural light display caused by charged particles from the sun interacting with the earth's atmosphere. When these particles collide with oxygen, yellows and greens are produced, with nitrogen they produce reds, violets and rarely blues
The night sky is a dark place, with only the moon and stars to cast any light. But throughout the long winters high in the northern hemisphere there are nights that are illuminated with spectacular displays of green and blue light dancing across the skies. We are talking, of course, about the Northern Lights. The Aurora borealis, to give them their proper name.