Overview
About Northern Lights
How the colours form
Auroras result from energetic particles exciting gases high above Earth. As those gases release energy, they emit light. Oxygen produces green and red, while nitrogen contributes blue and pink shades. Colour depends on the gas involved, its energy state and altitude. The changing bands and curtains belong to processes in the upper atmosphere and near-Earth space, rather than sunlight reflected from clouds or ice.
Seeing auroras in Iceland
Visibility depends on more than auroral activity. Dark skies and sufficiently clear weather are needed to see the display from the ground. The Icelandic Meteorological Office therefore presents cloud cover alongside its aurora activity forecast. These describe different parts of the same viewing problem: a forecast of strong activity does not mean the sky below will be clear.
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