geomagnetism

ge·o·mag·ne·tism

G0093700 (jē′ō-măg′nĭ-tĭz′əm)n.1. The magnetism of the earth.2. The study of the earth's magnetism.

ge′o·mag·net′ic (-nĕt′ĭk) adj.ge′o·mag·net′i·cal·ly adv.

geomagnetism

(ˌdʒiːəʊˈmæɡnɪˌtɪzəm) n1. (General Physics) the magnetic field of the earth2. (General Physics) the branch of physics concerned with this geomagnetic adj

ge•o•mag•net•ism

(ˌdʒi oʊˈmæg nɪˌtɪz əm)

n. 1. the earth's magnetic field and associated phenomena. 2. the branch of geophysics that studies such phenomena. [1935–40]

ge·o·mag·ne·tism

(jē′ō-măg′nĭ-tĭz′əm) The magnetic properties of the Earth. ♦ The magnetic field surrounding the Earth is called the geomagnetic field.

Translations

γεωμαγνητισμόςgeomagnetismo

geomagnetism

geomagnetism:

see magnetismmagnetism,
force of attraction or repulsion between various substances, especially those made of iron and certain other metals; ultimately it is due to the motion of electric charges.
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geomagnetism

(jee-oh-mag -nĕ-tiz-ăm) The Earth's magnetic field (or its study), which at the Earth's surface approximates that of a bar magnet at the center of the Earth with its axis inclined by 11.4° to the Earth's rotation axis and somewhat off-centered: the north magnetic and geographical poles are much closer together than the south poles. Both sets of poles wander in position. The strength of the magnetic field varies from 0.6 gauss near the magnetic poles to 0.3 gauss near the equator, i.e. from 60–30 microtesla, but can depart by up to 20% from the average without any correlation with major surface features. The dipole field changes only slowly with time but there are larger local variations in strength and direction. Violent short-term fluctuations occur during geomagnetic storms. Studies of magnetized rocks show that the entire magnetic field has reversed in direction about twice every million years in the past 165 million years. Complete reversals (i.e. north pole switching from pointing toward geographic north to pointing south, or vice versa) can occur within a few thousand years. The source of the geomagnetic field is believed to lie in a complex dynamo action in the Earth's liquid iron-rich outer core. Convective motion in this rotating electrically conducting fluid, in the presence of a magnetic field, generates electric currents; these in turn induce a magnetic field. Hence the Earth's field has been maintained. The field existed since at least 2.5, probably 3.5, thousand million years ago. See also magnetosphere; ring current.

geomagnetism

[¦jē·ō′mag·nə‚tiz·əm] (geophysics) The magnetism of the earth. Also known as terrestrial magnetism. The branch of science that deals with the earth's magnetism.

单词	geomagnetism
释义	geomagnetism ge·o·mag·ne·tism G0093700 (jē′ō-măg′nĭ-tĭz′əm)n.1. The magnetism of the earth.2. The study of the earth's magnetism. ge′o·mag·net′ic (-nĕt′ĭk) adj.ge′o·mag·net′i·cal·ly adv. geomagnetism (ˌdʒiːəʊˈmæɡnɪˌtɪzəm) n1. (General Physics) the magnetic field of the earth2. (General Physics) the branch of physics concerned with this geomagnetic adj ge•o•mag•net•ism (ˌdʒi oʊˈmæg nɪˌtɪz əm) n. 1. the earth's magnetic field and associated phenomena. 2. the branch of geophysics that studies such phenomena. [1935–40] ge·o·mag·ne·tism (jē′ō-măg′nĭ-tĭz′əm) The magnetic properties of the Earth. ♦ The magnetic field surrounding the Earth is called the geomagnetic field. Translations γεωμαγνητισμόςgeomagnetismo geomagnetism geomagnetism: see magnetismmagnetism, force of attraction or repulsion between various substances, especially those made of iron and certain other metals; ultimately it is due to the motion of electric charges. ..... Click the link for more information. . geomagnetism (jee-oh-mag -nĕ-tiz-ăm) The Earth's magnetic field (or its study), which at the Earth's surface approximates that of a bar magnet at the center of the Earth with its axis inclined by 11.4° to the Earth's rotation axis and somewhat off-centered: the north magnetic and geographical poles are much closer together than the south poles. Both sets of poles wander in position. The strength of the magnetic field varies from 0.6 gauss near the magnetic poles to 0.3 gauss near the equator, i.e. from 60–30 microtesla, but can depart by up to 20% from the average without any correlation with major surface features. The dipole field changes only slowly with time but there are larger local variations in strength and direction. Violent short-term fluctuations occur during geomagnetic storms. Studies of magnetized rocks show that the entire magnetic field has reversed in direction about twice every million years in the past 165 million years. Complete reversals (i.e. north pole switching from pointing toward geographic north to pointing south, or vice versa) can occur within a few thousand years. The source of the geomagnetic field is believed to lie in a complex dynamo action in the Earth's liquid iron-rich outer core. Convective motion in this rotating electrically conducting fluid, in the presence of a magnetic field, generates electric currents; these in turn induce a magnetic field. Hence the Earth's field has been maintained. The field existed since at least 2.5, probably 3.5, thousand million years ago. See also magnetosphere; ring current. geomagnetism [¦jē·ō′mag·nə‚tiz·əm] (geophysics) The magnetism of the earth. Also known as terrestrial magnetism. The branch of science that deals with the earth's magnetism. MedicalSeemagnetism
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