These dancing celestial hues have been both feared and revered throughout history. Today, although we know their cause – charged particles ejected from the sun reacting with the earth’s atmosphere – they are no less awe-inspiring. Enormous curtains of bright green, red and blue sway among the stars. To see them, you must travel north to the Arctic circle, away from light pollution, on a clear, dark night when the solar winds are blowing. Wait, look up and you might just catch the greatest show on earth.