The Earth's Magnetosphere
How was the Earth’s Magnetosphere discovered?
The magnetosphere was discovered in 1958, the International Geophysical Year (IGY), by the Explorer I Satellite. Prior to this discovery, scientists didn’t know very much about it: they knew that there were electric currents flowing in space, but they didn’t know where these currents were flowing or why they were flowing.
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The term “magnetosphere” was coined in 1959 by Thomas Gold from Cornell University. He wrote: "The region above the ionosphere in which the magnetic field of the earth has a dominant control over the motions of gas and fast charged particles is known to extend out to a distance of the order of 10 earth radii; it may appropriately be called the magnetosphere." Picture from: http://www.news.cornell.edu/releases/June04/Gold-moondust72.jpg | ||
The Dynamo Effect
The cause of the Earth's magnetic field is not fully understood, but it is thought that fluid motion in the Earth's outer core moves liquid iron across an already existing, weak magnetic field and generates an electric current. This electric current then creates a magnetic field that also works with the Earth’s outer core’s fluid motion to create a secondary magnetic field. This system is called the dynamo effect.
Size and Shape of the Magnetosphere
| The Earth’s magnetosphere’s shape is molded by the distortion of the Earth's internal magnetic field, solar wind, and the interplanetary magnetic field. The distance to the edge of the magnetosphere from the middle of the Earth on the side facing the Sun is about 10-12 Earth radii. The distance from the center of the Earth to the magnetotail is thought to be over 200 Earth radii. Picture from: http://www.physicscentral.com/action/images/action-02-4-6.jpg |
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Solar Wind's Effects on the Earth's Magnetosphere
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Solar Wind is one of the main factors that affect the shape of the Earth’s magnetosphere. Solar wind can be halted by Interplanetary Coronal Mass Ejections (ICMEs). ICMEs are caused by the release of magnetic energy from the Sun. When this solar plasma impacts the Earth's magnetosphere it temporarily distorts its shape. These impacts can cause magnetic reconnection in the Earth's magnetotail, which then shoots charged particles into the Earth's atmosphere, where it is seen as the aurora. Picture from: http://www.nsaclub.org/pictures/members /195-aurora-02.jpg | ||
