Northern Light, 1992

Northern lights occur between 60 and 120 miles above the surface of the Earth, caused by high-speed electrons colliding with air
molocules composed of oxygen and nitrogen. The stongly bound electrons of the atoms, excited to a higher energy-level by the
high-speed electrons, emit light when they return to a lower energy-level.
This artistic and scientific experiment was done thanks to the assistance of Prof. Eigil Ungstrup and Dr. Inger Marie Ungstrup
and the Institute of Geophysics, The University of Copenhagen.