The Northern Lights, more properly known as the Aurora Borealis, have long enchanted visitors to Iceland. With their dazzling colors and otherworldly glow, they might look like magic, but the science behind them is well understood: The shimmer arises when electrons from solar winds interact with the earth’s atmosphere, and the flowing, stream-like movements result because the winds follow the planet’s magnetic force.

Mostly green – the result of wind interaction with oxygen molecules about 60 miles above the earth – they can sometimes glow red when higher altitude molecules are encountered. Captured here in all their glory by photographer Ragnar Th. Sigurdsson, it’s not hard to see why they are one of the country’s top attractions.

(See more of Ragnar’s stunning photography on LightBox: High Above the Glacier)