Northern Lights

Northern Lights 

Of all naturally occurring heavenly phenomena, few come close to a night with a magnificent northern lights display. Flickering curtains of dancing light against the dark skies, northern lights is certainly one of the most spectacular of nature's phenomena. Northern Lights can be anything from a vague green mist to a complete firework, but always enough to make you stop and gaze into the vast sky. The Northern Lights can be scenery beyond imagination, when seen under the right circumstances. White, yellow, green and red, they sweep across the dark sky in a state of eternal, rapid flux.

Altitude and Colours

Altitude affects the colours of northern lights. The strong, green light originates at altitudes of 120 to 180 kilometres. Red northern lights occur at even higher altitudes, while blue and violet occur mostly below 120 kilometres. When the sun is "stormy", red colour occur at altitudes between 90 to 100 kilometres. Entirely red northern lights are sometimes seen, particularly at lower latitudes, and are often mistaken for a fire on the horizon

What is Northern Light?

Northern lights originate from our sun. During large explosions and flares, huge quantities of solar particles are thrown out of the sun and into deep space. These plasma clouds travel through space with speeds varying from 300 to 1000 kilometres per second. But even with such speeds (over a million kilometre per hour), it takes these plasma clouds two to three days to reach our planet. When they are closing in on Earth, they are captured by Earth's magnetic field (the magnetosphere) and guided towards Earth's north and south pole. On their way down towards the geomagnetic poles, the solar particles are stopped by Earth's atmosphere, which acts as an effective shield against these deadly particles. When the solar particles are stopped by the atmosphere, they collide with the atmospheric gases present, and the collision energy between the solar particle and the gas molecule is emitted as a photon - a light particle. And when you have many such collisions, you have an aurora - lights that may seem to move across the sky.

When to see Northern Lights

In Ammassalik, northern lights are more frequent in late autumn to early spring. October – beginning of April are the best months to see northern lights. NL are most frequent and intense from 10 p.m. to midnight, magnetic time. Brilliant auroras often occur at 27-day intervals as active areas on the sun's surface face earth during its 27-day rotation cycle. Northern lights activity corresponds closely to sunspot activity, which follows an 11-year cycle, but there seems to be a one-year delay between sunspot maximum and maximum auroral occurrence. Northern lights activity is 20-30% less during solar minimum than at solar maximum.

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