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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 . . 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.northernlights.no/english/measurements/poes.shtml http://www.northern-lights.no/english/what/planets.shtml Story . . . http://ds9.ssl.berkeley.edu/auroras/story.html . . . . More Cool Websites • Mythology of Auroras http://www.northernlights.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 Images of Aurora Australis are Provided With Many Thanks to Karina Leppik and Chris Martin (her better half)…