Matt, Alvin, Sonny
Berlin
Physics
3/18/11


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The Cause of an Aurora Borealis
The Northern Lights result from when storms on the surface of the sun form solar winds (Scientists call this solar activity a coronal mass ejection, CME), which then send charged particles towards the earth in large amounts. (This amount of power is equivalent to the power that is able to light up Los Angeles). The general time interval for this to take place is roughly three days for these streams of particles to reach the earth's ionosphere, in other words, earth's upper atmosphere. These atoms (particles) become excited/high states of energy that want to get to a lower or a more normal state of energy. In the process these excited atoms give off excess energy in the form of heat. This excess energy is the light that makes up the aurora borealis. These atoms come in the quantity of trillions and give off enough light energy so that a person would be able to see this light from 43 to 200 miles above them from the ground.
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A model representation of the formation of the aurora borealis

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Relativity to Magnetism
On this planet, particles of energy that form the aurora borealis come from the geospace environment, the magnetosphere and these particles (mostly electrons) travel along magnetic field lines. The Northern Lights are present at both North and South poles of the earth because the earth acts like a dipole magnet where field lines are going into the earth, near both N/S poles. The charged particles are blown out from high speeds of 1-4 million km/hr. The electricity of the gases cause the light of the aurora to appear in the atmosphere.
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View of an aurora borealis in the Northwest.
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Colors of the Aurora Borealis.
The most commonly observed color of the aurora borealis is a green color. Although this may be the case for many occasions, different colors are possible to occur. There have been many times where red, blue, or purple colors have been seen to show up in the aurora borealis. These colors do not vary from random, but instead they are formed because of the interaction of the atoms and the altitude of the earth's atmosphere. For the green light to appear, oxygen atoms must reach up to 150 miles in altitude. Appearance of the red light requires the oxygen atoms to interact with the atmosphere above 150 miles in altitude. For the blue and purple light, a different type of atom must be present. The nitrogen atom is to be interacted with the atmosphere up to 60 miles in altitude for the blue light, and above 60 miles in altitude for the purple light to appear. Here is a graph to show a visual appearance of the altitudes and colors.
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Variation of altitudes and colors of the aurora borealis

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Facts about the Aurora Borealis
  • The Northern Lights are found at locations that are in close proximity to the earth's poles such as Canada, Alaska, Antartica and have been seen at places such as Southern Mexico.
  • The colors and patterns are from atoms being energized as they collide with the magnetic filed of earth's atmosphere.
  • North American Inuit call the aurora "aqssarniit" or football players; the legend is that these lights are the spirits of the dead playing football with the head of a walrus.
  • The earliest known account of an aurora borealis is from a Babylonian clay tablet made by King Nechadenezzar sometime around 560 BC.
  • Aurora's have been found to have been occuring on other planets because if a planet has an atmosphere then there are charged particles as well. Planets such as Jupiter and Saturn have very earth like aurora's.
  • The Aurora Borealis most often occurs from September to October and from March to April.




Works Cited"Aurora FAQ." Aeronomy and Auroral Physics at the GI. Web. 17 Mar. 2011. <http://odin.gi.alaska.edu/FAQ/#cause>."How Is the Aurora Made?" David Newman's Page. Web. 17 Mar. 2011. <http://ffden-2.phys.uaf.edu/211.fall2000.web.projects/Christina Shaw/HowAuroraMadehtml.html>."What Are the Northern Lights?(Everyday Mysteries: Fun Science Facts from the Library of Congress)." Library of Congress Home. Web. 17 Mar. 2011. <http://www.loc.gov/rr/scitech/mysteries/northernlights.html>."YouTube - Amazing Northern Lights Time Lapse." YouTube - Broadcast Yourself. Web. 17 Mar. 2011. <http://www.youtube.com/watch?v=FcfWsj9OnsI>.