Researchers from the University of Oslo have flown a rocket through the phenomena to take a closer look with the aim of gathering data that will help in predicting space weather.

The northern lights are caused by solar flares from the Sun. But these same solar flares are the source of more than just the Aurora Borealis. On the Earth's day side, sunlight strips electrons loose from the atmosphere, forming clouds of electrons that drift across the Arctic and, although they are invisible to our eyes, appear on radar screens and in super-sensitive cameras.

Within just a few hours, electron clouds that form during the day over North America can cross the Arctic and reach Scandinavia after being drawn out of the polar region by the northern lights.