What are the Northern Lights?
(Lansing State Journal, November 26, 1997)

Another common name for the Northern Lights is the Aurora Borealis.  An aurora is a shimmering ribbon or curtain of turquoise light containing patches of pink and red light.
 
Although we see the auroras here on Earth, they are caused by events near the Sun.  The Sun is surrounded by a halo of gas which is constantly expanding into space and spreading pieces of atoms in every direction.  This phenomenon is called the solar wind and it is made up of mostly protons and electrons. Protons are positively charged particles while electrons are negatively charged particles in an atom.
 
The Earth acts like one gigantic magnet with lines of magnetic force curving out into space and converging near the North and South poles.  Once the solar particles approach the Earth they are pulled in and travel along these lines until they are dumped into the Earth’s atmosphere.  When the solar particles collide with nitrogen and oxygen atoms in the atmosphere some of them become excited by gaining electrons, while other atoms lose their electrons.  As the excited atoms return to their normal energy state they release light.  Excited nitrogen atoms release red light while nitrogen atoms that have lost electrons emit violet and blue light.  Excited oxygen atoms emit green and red light. So charged particles emitted by the Sun cause the aurora here on Earth.

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