I was stumbling online the other day when I came across this awesome video of the fabled Northern Lights (Aurora Borealis) in Norway. If you’re like me, you enjoy finding out how things like the Aurora Borealis work. Pretty much what happens is the sun releases streams of charged particles known as solar winds. These particles include electrons, which follow a path created by the Earth’s magnetic field and eventually enter the magnetosphere. Once the electrons enter the upper atmosphere, they begin making contact with atoms of oxygen and nitrogen at varying altitudes. The kinetic energy gained from the electron striking the atom excites the atom, leading it to emit light.
The element and the altitude determine the colour of lights that are emitted – if the electron excites an oxygen atom at any height up to 250 km, we would see green light. Anything over 250 km, and we would see red light. On the other hand, if the electrons make contact with nitrogen atoms up to 100 km, we would observe blue light, whereas anything over 100 km would result in violet light. Usually, we see some combination of these 4 colours, as the electrons strike many atoms in the atmosphere – up to 20 million per second!
If you aren’t particularly interested by the science, I hope that you at least enjoy the video! 😀
[vimeo 21419634]