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Earth as a Magnet

Earth as a Magnet. www.scifun.ed.ac.uk. Why Earth has a Magnetic Field. Dynamo Effect Earth’s Core contains molten metal (iron and nickel – ferromagnetic!) that circulates (due to convection currents) Circulating Metal causes Electric Currents Magnetic Field. http://geomag.usgs.gov.

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Earth as a Magnet

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  1. Earth as a Magnet www.scifun.ed.ac.uk

  2. Why Earth has a Magnetic Field Dynamo Effect Earth’s Core contains molten metal (iron and nickel – ferromagnetic!) that circulates (due to convection currents) Circulating Metal causes Electric Currents Magnetic Field http://geomag.usgs.gov

  3. Earth’s Core http://geomag.usgs.gov http://www.magnet.fsu.edu

  4. Why is Earth’s Magnetic Field Important? Our magnetic field protects the Earth from space weather/solar storms – the solar wind Protects atmosphere from being blown away Protects us from solar radiation Protects electronics used for communication and our power grid from being disrupted/destroyed http://www.suntrek.org

  5. Mar’s Magnetic Field • Since Mars’ core does not rotate it does not produce a global magnetic field. • The lack of magnetic field has caused Mars to experience a lot of solar radiation and for the solar wind to erode most of Mars’ atmosphere. • Mars once had a global magnetic field and that remnants remain. www.spaceflightnow.com

  6. Last flip about 780,000 years ago – generally flip every 200,000 years During a flip Earth’s magnetic field will weaken by up to 90%. Earth will also have multiple north and south poles. http://www.pbs.org/wgbh/nova/magnetic/timeline.html

  7. Magnetic Reversals Computer models show multiple poles and a weaker field http://science.nasa.gov/headlines/y2003/29dec_magneticfield.htm

  8. Earth as a Magnet Compass:has a magnetized needle that spins freely Points north Used for navigation

  9. Earth as a Magnet Earth has a magnetic field and two poles just like a bar magnet http://www.mag-net.org.uk/earthfield.gif

  10. Earth’s Magnetic Field Earth’s magnetic field can cause ferromagnetic materials to become magnets over time Magnetic domains of the material eventually line up with Earth’s field http://son.nasa.gov

  11. Earth’s Magnetic Poles The Geographic North Pole is a magnetic south pole! The magnetic north pole is in Antarctica with the penguins! The geographic and magnetic poles are not in the same locations Based on the fact that compass needles point north, where is the magnetic north pole? Is it with the polar bears in the Arctic or with the penguins in the Antarctic? http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magearth.html

  12. Magnetic Declination Angle between the geographic north and the north to which a compass needle points (magnetic pole in the northern hemisphere) This angle depends on where you are on Earth Changes over time since magnetic poles drift over time

  13. The Moving Poles http://gsc.nrcan.gc.ca/geomag/nmp/northpole_e.php http://science.nasa.gov/headlines/y2003/29dec_magneticfield.htm

  14. The pole shifts constantly – loops up 80 km a day(due to solar radiation changes)- so recorded location an averageIn 2009 it was moving 40 miles a year (25 miles a year in 2005)Moved 685 miles in the last centuryCurrently in Canada – moving towards Russia

  15. Moving Poles freerepublic.com blog.mtnspirit.org

  16. Moving Poles http://www.earthweek.com http://www.compassdude.com/

  17. Moving Poles http://www.ngdc.noaa.gov

  18. Moving Poles

  19. Solar Wind High speed stream of electrically charged particles coming from the sun www.scifair.org/

  20. Solar Wind http://www.nasa.gov

  21. Magnetosphere The area of the magnetic field shaped by the solar wind Particles can reach the Earth’s surface at the poles by following the magnetic field lines Earth’s magnetic field can affect electrically charged particles in space…the particles can also affect the magnetic field http://yesserver.space.swri.edu

  22. Magnetosphere

  23. Van Allen Belts http://geomag.usgs.gov Doughnut shaped areas between 1,000 and 25,000 km above the Earth. Protons and electrons traveling at high speeds are found there Found within the magnetosphere

  24. The Magnetosphere http://www.solcomhouse.com/ http://www.aero.org

  25. Auroras Solar wind energizes the magnetosphere which can cause the acceleration of electrons there. Energy from the solar wind is transferred to atoms of Nitrogen and Oxygen in the upper atmosphere. This energy “excites” electrons in the atoms. When the electrons return to normal the atoms emit light

  26. Auroras http://www.nasa.gov

  27. Auroras Color depends on the type of atom that is excited and how excited it becomes Normally seen at the poles, but can be seen as far south as Florida (and Cuba)! Aurora borealis in the north and aurora australis in the south

  28. Aurora

  29. Where to Find These Aurora Pictures from NASA Aurora Information Pamphlet from NASA

  30. Animals Scientists have studied how turtles, homing pigeons, lobsters, bats, rats, cattle, etc sense and use Earth’s magnetic field. The animals use the field for navigation: knowing which direction they are traveling + their location How would changing the Earth’s magnetic field affect these animals?

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