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A geomagnetic reversal is a change in a planet's dipole magnetic field such that the positions of magnetic north and magnetic south are interchanged (not to be confused with geographic north and geographic south). The Earth's magnetic field has alternated between periods of normal polarity, in which the predominant direction of the field was ...
A magnet's North pole is defined as the pole that is attracted by the Earth's North Magnetic Pole when the magnet is suspended so it can turn freely. Since opposite poles attract, the North Magnetic Pole of the Earth is really the south pole of its magnetic field (the place where the field is directed downward into the Earth). [20] [21] [22] [23]
The geographic poles are defined by the points on the surface of Earth that are intersected by the axis of rotation. The pole shift hypothesis describes a change in location of these poles with respect to the underlying surface – a phenomenon distinct from the changes in axial orientation with respect to the plane of the ecliptic that are caused by precession and nutation, and is an ...
A geomagnetic excursion, like a geomagnetic reversal, is a significant change in the Earth's magnetic field.Unlike reversals, an excursion is not a "permanent" re-orientation of the large-scale field, but rather represents a dramatic, typically a (geologically) short-lived change in field intensity, with a variation in pole orientation of up to 45° from the previous position.
The Laschamp or Laschamps event [note 1] was a geomagnetic excursion (a short reversal of the Earth's magnetic field). It occurred between 42,200 and 41,500 years ago, during the end of the Last Glacial Period. It was discovered from geomagnetic anomalies found in the Laschamps and Olby lava flows near Clermont-Ferrand, France in the 1960s. [1][2]
Paleomagnetism (occasionally palaeomagnetism) is the study of prehistoric Earth's magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called paleomagnetists. Certain magnetic minerals in rocks can record the direction and intensity of Earth's magnetic field at the time they ...
Studying dynamo models has utility in the field of geophysics as doing so can identify how various mechanisms form magnetic fields like those produced by astrophysical bodies like Earth and how they cause magnetic fields to exhibit certain features, such as pole reversals. The equations used in numerical models of dynamo are highly complex.
The geomagnetic north pole is the northern antipodal pole of an ideal dipole model of the Earth's magnetic field, which is the most closely fitting model of Earth's actual magnetic field. The north magnetic pole moves over time according to magnetic changes and flux lobe elongation [2] in the Earth's outer core. [3]