polar lights

The 'auroral zone' is a region between between 10° and 20° from the geomagnetic poles, in which the polar lights occur. The lights are present at all times, but most visible against a clear, dark sky.
During the long nights of the winter seasons, the lights provide a weak, but near-constant illumination.
The cause of the polar lights are the subject of ongoing enquiry, with multiple possible mythological and scientific explanations. The prevailing scientific theory is that the lights are produced by the intersection of Reality and Dream, and the presence of figures or cities visible in the lights is the spirit world made visible to the naked eye. Cultural explanations include visions of the afterlife, visions of the forelife, visions of the past and/or future, an alternate reality, magic entering the world, and the disintegration of Reality.

Forms

Polar lights come in a number of different forms and intensities:

• A mild glow near the horizon. This form resembles clouds lit by moonlight, and appears at the edge of visibility.
• Patchy lights and cloud-like formations
• Ribbon lights, which may also look like curtains or hanging fabric
• Vertical stripes
• Arcs, which create bridge-like structures between points on the horizon

Colours

Green

The most common colour, green aurorae occur year-round

Red

Most visible around midnight on the winter solstice. Red polar light is saturated and dark and may be almost indistinguishable from the night sky. Outsde of the solstice, red light occurs at the upper ends of ribbons and along the top edge of arcs.

Blue and purple

Mainly occurring at the lower edge of arcs and curtains, blue and purple lights are more common at the equinoxes, especially in the northern hemisphere.

Minor colours: yellow, pink, and orange

Seen as flashes, stripes or rays within a larger lightshow, these colours are rare and are considered a good omen by cultures for whom the polar lights have positive connotations.

Black and ultra-black

The polar and subterranean cultures of the Golyan Confederation place particular emphasis on the negative spaces between the lights. The differences between black and ultra-black aurorae are not visible to non-ljudoy without specialist scientific instrumentation.

Noise

Some observers report hearing a noise similar to a softly hummmed tune they describe as 'soothing', 'restful' or 'calming'. It induces a relaxed state, and can be soporific, which may be dangerous if the observer is a situation where they may become hypothermic, but the noise itself does not appear to be detrimental and may have some health benefits.

Type

Natural