Aurora is caused by collisions between electrically charged particles released from the sun that 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" and auroras that occur in the southern hempishere are called "Aurora Australis" or "southern lights".
Both Auroras can be seen in the northern or southern hemisphere, in an irregularly shaped oval centred over each magnetic pole. 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 colours. 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.