"The northern lights have seen queer sights / but the queerest they ever did see / Was that night on the marge of Lake Lebarge / I cremated Sam McGee."

So the American poet Robert Service began his classic "The Cremation of Sam McGee," one of many poems he wrote about the arctic, a land which often witnesses the shimmering curtains of light called the aurora borealis.

As a widespread and highly visible phenomenon, the aurora has certainly been known to humans since long before written records developed. Often greenish but occasionally reddish-pink, aurorae occur chiefly in the northern latitudes and can over the entire sky. Probably aurorae instilled both awe and fear in the minds of these ancient peoples, who regarded celestial events as divine doings, often presaging unhappiness or ill fortune.

Written records of the occurrence of aurorae can be traced back to the ancient Chinese and Greek civilizations...