Auroras

Set-up picture of a northern light in Siberia. Source: http://goo.gl/y07Rb

A northern light (or as usually called Aurora Borealis) is a natural phenomenon we can see in high latitudes. In low latitudes (South Pole) they're called southern lights or Aurora Australis.




They're caused when energetic solar particles tackle Earth's magnetic field and, as a result of that collision, what we see is that amazing mixture of colors in the sky.





Here (http://en.wikipedia.org/wiki/Aurora_(astronomy)) you will find more info about this amazing phenomenon.