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Thesouth magnetic pole, also known as themagnetic south pole, is the point on Earth's Southern Hemisphere where thegeomagnetic field lines are directed perpendicular to the nominal surface. The Geomagnetic South Pole, a related point, is the south pole of an idealdipole model of the Earth's magnetic field that most closely fits the Earth's actual magnetic field.
For historical reasons, the "end" of a freely hanging magnet that points (roughly) north is itself called the "north pole" of the magnet, and the other end, pointing south, is called the magnet's "south pole". Because opposite poles attract, Earth's south magnetic pole is physically actually a magneticnorth pole (see alsoNorth magnetic pole § Polarity).
The south magnetic pole is constantly shifting due to changes in Earth's magnetic field.As of 2005 it was calculated to lie at64°31′48″S137°51′36″E / 64.53000°S 137.86000°E /-64.53000; 137.86000,[2] placing it off the coast of Antarctica, betweenAdélie Land andWilkes Land. In 2015 it lay at64°17′S136°35′E / 64.28°S 136.59°E /-64.28; 136.59 (est).[3] That point lies outside theAntarctic Circle. Due topolar drift, the pole is moving northwest by about 10 to 15 kilometres (6 to 9 mi) per year. Its current distance from the actualGeographic South Pole is approximately 2,860 km (1,780 mi).[1] The nearest permanent science station isDumont d'Urville Station. While the north magnetic pole began wandering very quickly in the mid 1990s, the movement of the south magnetic pole did not show a matching change of speed.
Early unsuccessful attempts to reach the magnetic south pole included those of French explorerJules Dumont d'Urville (1837–1840), AmericanCharles Wilkes (expedition of 1838–1842) and BritonJames Clark Ross (expedition of 1839–1843).[4]
The first calculation of the magnetic inclination to locate the magnetic South Pole was made on 23 January 1838 by the hydrographerClément Adrien Vincendon-Dumoulin [fr], a member of the Dumont d'Urville expedition in Antarctica and Oceania on thecorvettesL'Astrolabe andZélée in 1837–1840, which discoveredAdélie Land.
On 16 January 1909 three men (Douglas Mawson,Edgeworth David, andAlistair Mackay) from SirErnest Shackleton'sNimrod Expedition claimed to have found the south magnetic pole,[5] which was at that time located on land.[6] They planted a flagpole at the spot and claimed it for the British Empire. However, there is now some doubt as to whether their location was correct.[7] The approximate position of the pole on 16 January 1909 was72°15′S155°09′E / 72.25°S 155.15°E /-72.25; 155.15.[8][full citation needed]
The south magnetic pole has also been estimated by fits to global sets of data such as theWorld Magnetic Model (WMM) and theInternational Geomagnetic Reference Field (IGRF).[1] For earlier years back to about 1600, the model GUFM1 is used, based on a compilation of data from ship logs.[9]
Earth's geomagnetic field can be approximated by a tilted dipole (like a bar magnet) placed at the center of Earth. The south geomagnetic pole is the point where the axis of this best-fitting tilted dipole intersects Earth's surface in the southern hemisphere. As of 2005 it was calculated to be located at79°44′S108°13′E / 79.74°S 108.22°E /-79.74; 108.22,[10] near theVostok Station. Because the field is not an exact dipole, the south geomagnetic pole does not coincide with the south magnetic pole. Furthermore, the south geomagnetic pole is wandering for the same reason its northern geomagnetic counterpart wanders.