Question: What is the cause of the Aurora Borealis?

Joe Reed answered on 18 Nov 2014:

The sun ‘blows’ out a strong wind which is full of charged particles. These charged particles get into the ‘tail’ of our magnetosphere through magnetic field lines. A few times a day an event happens in the tail that shoots all these charged particles down Earth’s magnetic field lines into our North or South pole. These charged particles have lots and lots of energy, so when they hit the atoms in our atmosphere, they cause those atoms to lose their electrons which happens with a burst of light.
The Aurora is mostly green from oxygen and red from nitrogen, the two gases that make up most of our atmosphere.