AURORAS - Electricity & Magnetism in

Nature

Connie Walker

NOAO

A Brief History of Auroras

A Brief History of Auroras

• Norwegian chronicle: the King's Mirror (1230 AD)

• The aurora in the King's Mirror was said to be a natural phenomenon and was nicknamed Nordurljos, or northern lights.

• The scientific name, Aurora Borealis, is Latin and translates into the red dawn of the north. The Italian scientist, Galileo Galilei (1564-1642), first used the expression. Where Galileo lived, northern lights consist of mainly red color.

The Origin of Aurora

The Origin of Aurora

The Origin of Aurora

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The Origin of Aurora

The Origin of Aurora

In 1989, solar storms disrupted satellite transmission & power grids. Eastern Canada lost power for 9 hours.

Things Around the Earth We Cannot See

• Air (gases: nitrogen, oxygen, etc)• Magnetic Field

– Played with iron filings– Bar magnet at Earth’s center– Field lines we draw to represent it

• Poles: where field strongest? Weakest?

• A Plasma– Made up of charged particles (mostly electrons)– They spiral along the magnetic field lines

Plasma or energetic electrically charged particles (mostly electrons) accelerate along the magnetic field lines into the upper atmosphere, where they collide with gas atoms, causing the atoms to give off light.

Cool Website

• Solar wind, plasma, magneto-tail, aurora:

http://www.northern-lights.no/english/what/cause.shtml

Cool Websites

• Two good examples of an aurora (movies):

http://www.weatherpaparazzi.com/video/videodetail.asp?id=105

http://www.northern-lights.no/resources/gregcolors.wmv

• Auroral ovals around the poles today:

http://www.northern-lights.no/english/measurements/poes.shtml

http://www.northern-lights.no/english/what/planets.shtml

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http://ds9.ssl.berkeley.edu/auroras/story.html

Story

More Cool Websites

• Mythology of Auroras

http://www.northern-lights.no/english/mythology/index.shtml

http://www.wikipedia.org

http://www.encarta.com

http://www.nasa.gov

http://www.space.com

http://www.weatherpaparazzi.com/

http://ds9.ssl.berkeley.edu/auroras/story

http://www.northern-lights.no/

http://www.spaceweather.com/

The Following Imagesof Aurora Australis

are Provided With Many Thanks to

Karina Leppik and Chris Martin (her better half)…