The bright dancing lights of the aurora are actually collisions between electrically charged particles from the sun that enter the Earth’s atmosphere. The lights are seen above the magnetic poles of the northern and southern hemispheres. They are known as ‘Aurora Borealis’ in the north and ‘Aurora Australis’ in the south.
Auroral displays appear in many colours although pale green and pink are the most common. Shades of red, yellow, green, blue, and violet have been reported. The lights appear in many forms from patches or scattered clouds of light to streamers, arcs, rippling curtains or shooting rays that light up the sky with an eerie glow.
Causes for Northern Lights
The Northern Lights are actually the result of collisions between gaseous particles in the Earth’s atmosphere with charged particles released from the Sun.
Variations in colour are due to the type of gas particles that are colliding. The most common auroral color, a pale yellowish-green, is produced by oxygen molecules located about 60 miles above the earth. Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purplish-red aurora.
The connection between the Northern Lights and sunspot activity has been suspected since about 1880. Thanks to research conducted since the 1950’s, we now know that electrons and protons from the sun are blown towards the earth on the ‘solar wind’.
The lights of the Aurora generally extend from 80 kilometres (50 miles) to as high as 640 kilometres (400 miles) above the earth’s surface.
Best place to watch from
Northern Lights can be seen in the northern or southern hemisphere, in an irregularly shaped oval centred over each magnetic pole. The lights are known as ‘Aurora Borealis’ in the north and ‘Aurora Australis’ in the south.
Scientists have learned that in most instances northern and southern auroras are mirror-like images that occur at the same time, with similar shapes and colors.
Areas that are not subject to ‘light pollution’ are the best places to watch for the lights. Areas in the north, in smaller communities, tend to be best.
Best time to watch the celestial wonder
Researchers have also discovered that auroral activity is cyclic, peaking roughly every 11 years. Winter in the north is generally a good season to view lights. The long periods of darkness and the frequency of clear nights provide many good opportunities to watch the auroral displays. Usually the best time of night (on clear nights) to watch for auroral displays is local midnight.
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