Title says it all. After playing Skyrim for a while, my controller ran out of charge, so my TV was just stuck watching the Skyrim sky for ages while I hunted for the charger cable, which isn't a bad sight. When night fell, and the aurora lashed across the sky, I began to wonder what caused them, seeing as real auroras ( caused by the earth's magnetic field eating cosmic radiation) was obviously going to be nothing like TES.

So, what causes this? I heard a few theories about the Divines tinkering on the world, Daedra either peering inside or trying to enter, and other things. So, what causes them?

Magicka entering/flying-past Mundus from Magnus

Ah, well I should have seen that coming. Is there a source to that?