geomagnetism

(redirected from geomagnetic)
Also found in: Dictionary, Wikipedia.
Related to geomagnetic: Geomagnetic reversal, Geomagnetic field

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.
References in periodicals archive ?
If aimed toward Earth, it could result in a geomagnetic storm, a phenomenon that can affect power and navigation for satellites orbiting the Earth as well as radio communication.
Earth experienced a geomagnetic storm on June 22, 2015 due to the arrival of an Earth-directed coronal mass ejection, or CME, from June 20.
The storm ranks a 4 on the National Oceanic and Atmospheric Administration's (NOAA) 1 to 5 scale for geomagnetic effects.
Geomagnetic storms increase the earth's magnetic field and are most familiar to us in the context of aurora in high-latitude regions of earth and for disrupting satellite communication.
It's been hypothesized that monarchs use geomagnetic cues to help navigate when day light cues are unavailable to them during migration.
It had been hypothesized but never proven that they use geomagnetic cues when light cues are unavailable.
Space Weather Prediction Center under the National Oceanic and Atmospheric Administration has issued a geomagnetic storm watch for 2 April.
They cover diagnostics of plasma perturbations by using Doppler radio sounding, diagnostics of plasma wave disturbance by incoherent scatter and Doppler radars, diagnostics of geomagnetic disturbances, rocket burn and launch and radio communication, and ecological problems in near-the-earth space activity.
The Northern Lights, or aurora borealis, are usually visible in only the more northern parts of the UK, but a surge in geomagnetic activity on Thursday led to them appearing much further south than usual.
The Northern Lights are usually visible in only the more northern parts of the UK, but a surge in geomagnetic activity on Thursday led to them appearing much further south than usual.
Dubai: Islamic scholars have told worshippers they should not be concerned if their mobile applications fail to point to the correct direction of the kiblah (the direction of the Kba) due to the effect of the currently ongoing geomagnetic storm.