Northern Lights (Aurora Borealis)

After a fantastic day in Narvik, this beautiful northern light appeared on our way home. Luckily I had my camera and could take my very first photo of this spectacular phenomena!

An aurora  is a colorful light that an be seen in the sky at the polar regions. Depending on which pole you see the aurora it is named northern- or southern light alt aurora borealis for the northern pole or aurora australis for the southern pole.

The aurora is caused by collisions from charged particles of high speed, with the Earths atmosphere. The light is created in the upper part of the Earths atmosphere, the ionosphere. 



Our Sun is the source of the high speed particles. When one of these particles enter the Earths atmosphere, it will collide with atoms and molecules in the Earths atmosphere. And when it does, the particle loses some of its energy to the atom. But the atom now has too much energy and therefore release a photon, a light. The particle continues to move, but now with lower speed, until it collide with another atom and loses some more energy. Also that atom will release a light. Every time the particle collide with an atom, the atom will release light and the particle will lose some more of its energy. Eventually the particle will have lost all its energy and will stand still. When the particle collide with different atoms and molecules we will see this light as an aurora.

Depending on the particles speed, the altitude of collision and what kind of atoms and molecules the particle will collide with, the light will look differently.  Depending on altitude, the collision with oxygen will give a green, red or brownish color. Collisions with nitrogen will give a color of blue or red. 



The most common color is green. Pure blue is the most rare one, as it is created at very low altitudes.