How does the phenomenon occur?
The northern lights are a physical phenomenon that occurs when electrically charged particles from the sun hurtle towards the Earth. The light becomes visible when the particles collide with gases in the Earth's atmosphere. The Earth’s magnetic field directs the particles towards the openings near the North and South Poles, and thus the phenomenon can only be observed near the magnetic poles. The polar light in the northern hemisphere is called aurora borealis - or northern lights - while the polar lights in the southern hemisphere are called aurora australis, the southern lights.
The colour spectrum of the northern lights
The northern lights can be many different colours. This is determined by the gases with which the particles from the sun collide. This, in turn, is determined by the altitude at which the collision takes place in the atmosphere. The visible northern lights are from 90 to approximately 150 kilometres above the Earth's surface, and the colours can be categorised roughly as follows:
- More than 150 kilometres: Red light
- 120 km - 150 kilometres: Yellow-green light
- Less than 120 kilometres: Blue-purple light
How often can you see the northern lights?
The northern lights are influenced by activity on the sun, and strong solar winds increase and intensify the northern lights. The northern lights are therefore always present. Historically, the chances of seeing the northern lights are best viewed in Northern Norway between October and March, because the polar night makes them easier to see.
Where can you see the northern lights?
The northern lights are visible in a belt around the magnetic North Pole. Because of their location and accessibility, the counties of Nordland, Troms and Finnmark are perfect as a base for experiencing the northern lights. Northern Norway also offers a number of other activities that, combined with the northern lights, can make your trip truly unique.
When can you see the northern lights?
It must be a dark, cloudless night for the northern lights to be visible. Northern Norway during the polar night is therefore your best bet for experiencing the northern lights. Experience shows that the northern lights shine most often and strongest a few hours before and after midnight. The northern lights are strongest when an active area on the sun’s surface faces Earth. Spectacular displays of the northern lights thus occur at roughly 27-day intervals, the time it takes the sun to rotate once. October, February and March are the best months for seeing the aurora borealis.