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Magnetic Field of the Earth. What makes it so? Aaron Lariscy. Discovery of the Poles. In the 1600’s William Gilbert published his great study on magnetism "De Magnete “ It gave the first rational explanation of why a compass worked…. the earth itself was a magnet.
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Magnetic Field of the Earth What makes it so? Aaron Lariscy
Discovery of the Poles • In the 1600’s William Gilbert published his great study on magnetism "De Magnete“ • It gave the first rational explanation of why a compass worked…. the earth itself was a magnet.
Other uses of the Earths Magnetic Field • The earths magnetic field serves other purposes. • One of the more important is a shield from the radiation of the sun.
Switching poles? • Scientist believe the poles switch every 200,000 years. • Scientist guess the last time this occurred was around 780,000 years ago. • Scientists believe this may happen again soon due to the fact the poles move 20km a year and magnetic field has fallen by 1%.
So.. What causes the magnetism? • The common theory of how it happens is the Geodynamo or Dymano theory.
Basic Principals.. • The basic principals rely on the molten steel in the earths core. • As the outer edges of the molten core of the earth cool the displace the molten inner core. • This molten core is therefore pushed to the surface and due to earth’s rotation flows in a helical motion.
This motion causes friction between the more solid outer core and the helical flowing molten steel creating a current. • This current is responsible for creating the earths magnetic properties.
This is only one theory • Another simpler theory is that the core of the earth is a solid spherical shaped magnet. • No one idea explains everything so basically no one knows 100% why the earth has a magnetic field.
In conclusion • The simple question “how does the earth get its magnetic field” does not have a simple answer. • Its is fairly clear that is somehow relates to the rotation of the earth but exactly how is not clear.
Sources C. Johnson “Source of the Earths Magnetic Field” 02/12/2008 . 04/23/2008 http://mb-soft.com/public/tecto2.html. R. Nave “Magnetic Field of the Earth” 04/23/2008. http://hyperphysics.phy-astr.gsu.edu/Hbase/magnetic/MagEarth.html Dr. David P. Stern “The Great Magnet, the Earth” 11/20/2003 . 04/23/2008 http://www-istp.gsfc.nasa.gov/earthmag/