WHAT IS THE AURORA BOREALIS?
The Aurora Borealis is an incredible light show caused by collisions between electrically charged particles released from the sun. They then enter the earth’s atmosphere and collide with gases such as oxygen and nitrogen. The lights are seen around the magnetic poles of the northern and southern hemispheres.
Auroras that occur in the northern hemisphere are called ‘Aurora Borealis’ or ‘northern lights’. The auroras that occur in the southern hempishere are called ‘Aurora Australis’ or ‘southern lights’.
Auroral displays can appear in many vivid colours, although green is the most common. Colours such as red, yellow, green, blue and violet are also seen occasionally. The auroras can appear in many forms, from small patches of light that appear out of nowhere to streamers, arcs, rippling curtains or shooting rays that light up the sky with an incredible glow.
WHAT CAUSES THE AURORA?
Auroras are the result of collisions between gaseous particles (in the Earth’s atmosphere) with charged particles (released from the sun’s atmosphere). Variations in colour are due to the type of gas particles that are colliding. The most common aurora colour which is green, is produced by oxygen molecules located about 60 miles above the earth. The rarer red auroras are produced by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purple aurora.
While the northern reaches of Scotland offer better chances of spotting the ‘Mirrie Dancers’, the aurora can be seen anywhere in Scotland when the right conditions are met and where the light pollution is at a minimum.
WHEN TO SEE THE NORTHERN LIGHTS?
Autumn and winter seasons, with their long periods of darkness and the frequency of clear nights, are probably the best time of the year to experience the auroral displays. Nights need to be cold and the sky clear of clouds, with limited light pollution and increased solar activity. Staying up until the wee hours of the morning or camping may also help.
Images: Marc Hilton