geomagnetism

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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.
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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.
References in periodicals archive ?
Such a rapid change over such a small area marks out the geomagnetic spike as one of the most extreme variations of Earth's magnetic field ever recorded.
The development of living systems from single cell to multicellular organisms occurred within the geomagnetic field.
Given the limited historical geomagnetic data and because scientific understanding of such disturbances is still evolving, FERC directed NERC to conduct further research on specific GMD issues.
Scientists can use the bevy of electron energy level observations to hypothesize and subsequently model in rigorous detail what is happening inside the Van Allen belts, both during and in between geomagnetic storms.
Improving forecasts and studying auroras are important because auroras are features of geomagnetic storms.
Following Malkin (2013), a possible jerk in 1994 was also added, which can be observed in the geomagnetic data obtained at several observatories (Nagao et al.
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.
This storm ranks a 4, called severe, on the National Oceanic and Atmospheric Administration's 1-to-5 scale for geomagnetic effects.
The storm ranks a 4 on the National Oceanic and Atmospheric Administration's (NOAA) 1 to 5 scale for geomagnetic effects.
The BMI160 achieves this by synchronising the inertial accelerometer and gyroscope sensor data precisely with external geomagnetic sensor data, and is ideally suited for applications requiring exact, low latency low power nine-axis sensor data fusion.
The research, published in the journal Nature Communications, shows that monarchs use an internal compass that relies on both ultraviolet light and geomagnetic cues.