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
.