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The aurora borealis, otherwise known as the Northern Lights, is one of the finest sights in nature. It is caused by electrically charged particles emitted by the sun and interacting with the earth's magnetic field. Some particles (chiefly electrons) are accelerated towards the earth and guided towards two zones, one near the north pole, the other near the south pole. Colliding with the upper atmosphere at very great speeds, the particles cause the air to glow in the beautiful colours of the aurora.

Iceland happens to be in the middle of the auroral zone where the phenomenon is most frequently seen. In fact, some aurora can be seen on almost every clear night in Iceland when the sky is dark enough, but its intensity is extremely variable. A brilliant display can be observed even from a brightly lit street or a hotel window, but to appreciate fully the splendour and exquisite colours of the aurora, you should try to get as far as possible from man-made illumination.

In Iceland the aurora is most frequently seen shortly before midnight, from about 21:00 to 01:00 local time (GMT). The brightest auroras are usually seen in the spring and autumn rather than midwinter, but a release of particles from the sun can create fine displays at any time. The aurora often forms arcs across the sky in a direction from southwest to northeast, at right angles to a compass needle. Sometimes long rays are seen, converging towards a point near the zenith. This phenomenon is known as the "corona". The aurora is much higher in the atmosphere than any jet plane can fly. The lower border of auroral arcs is generally about 100 km (60 miles) above the earth, while the highest rays can reach 1100 km (600 miles).

Places near to Reykjavík where the aurora may be observed with minimum interference from city lights include Heiðmörk (about 10 km away) Nesjavallavegur (20 km) and Krísuvík (30 km).

What are the northern lights?
Northern lights are bright lights in the sky. The northern lights are seen during the cold winter nights. In addition to the radiation from the sun, small chop particles fly towards the earth. As they approach the atmosphere, "flaming" lights appear on the northern sky. In the bright nights in Iceland we can see the northern lights quite clearly. The earths magnetic field in principle prevents particles to access the atmosphere but in the magnetospheres magnetic field there are areas where the particles get inside. The particles' motion energy is in this phase yet too little to be noticed by the bare eye. When the solar wind is peaceful, particles get into the atmosphere and northern lights do occur but they are too dark to be seen. During northern lights, there are powerful electric currents that move at a speed of over 100 km/hr in the ionosphere and magnetosphere, which can be observed on the ground as fast changes in the magnetic fields.

Northern lights observation
From the earth the northern lights are researched by photographing the night sky happenings, which are recorded through a fish eye lens. The optic that covers the entire sky gets the northern lights filmed from an area whose diameter is about 600 kilometers. Automatic cameras take pictures every night, usually at a one minute interval.

Prognosis for northern lights
Northern lights forecasting is based on observing the sun. When the researchers observe a particle eruption in the sun, there is a outlook of northern lights in a couple of days. We know that northern lights are showing northern lights ovals and that they are caused by interaction process between the solar wind and the magnetosphere. But we are not able to say when the northern lights discharge begins or what causes its end.

Sources: Þorsteinn Sæmundsson, Science Institute, University of Iceland.

More Northen Lights photos are in our Northern Lights photogallery.

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