The Polar Aurora ("Northern Lights")

  Aurora on 6 January 1998 (Dick Hutchinson ©)

           

The ribbons of the aurora are caused by fast electrons accelerated along magnetic field lines, which guide them into the high polar atmosphere.

Their glow arises around 100 km (60 miles), when they hit the denser atmosphere,.

Learn more on the web page   Secrets of the Polar Aurora.