South Magnetic Pole
Encyclopedia
The Earth
's South Magnetic Pole is the wandering point on the Earth's surface where the geomagnetic field
lines are directed vertically upwards. It should not be confused with the lesser known South Geomagnetic Pole described later.
For historical reasons, the "end" of a magnet that points (roughly) north is itself called the "north pole" of the magnet, and the other end, pointing south, is called magnet's "south pole". Because opposite poles attract, the Earth's South Magnetic Pole is physically actually a magnetic north pole (see also North Magnetic Pole – Polarity).
The South Magnetic Pole is constantly shifting due to changes in the Earth's magnetic field.
As of 2005 it was calculated to lie at 64°31′48"S 137°51′36"E, just off the coast of Adelie Land
, French Antarctica. That point lies outside the Antarctic Circle
. Due to polar drift
, the pole is moving north west by about 10 to 15 kilometers per year.
(expedition of 1838–42) and Briton James Clark Ross
(expedition of 1839–43).
On January 16, 1909 three men (Douglas Mawson
, Edgeworth David
, and Alistair Mackay
) from Sir Ernest Shackleton's Nimrod Expedition
claimed to have found the South Magnetic Pole, which was at that time located on land. However, there is now some doubt as to whether their location was correct.
The approximate position of the pole on 16 January 1909 was 72.25°S 155.15°E.
(WMM) and the International Geomagnetic Reference Model
(IGRF). For earlier years back to about 1600, the model GUFM1 is used, based on a compilation of data from ship logs.
. 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 magnetic counterpart wanders.
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's South Magnetic Pole is the wandering point on the Earth's surface where the geomagnetic field
Earth's magnetic field
Earth's magnetic field is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun...
lines are directed vertically upwards. It should not be confused with the lesser known South Geomagnetic Pole described later.
For historical reasons, the "end" of a magnet that points (roughly) north is itself called the "north pole" of the magnet, and the other end, pointing south, is called magnet's "south pole". Because opposite poles attract, the Earth's South Magnetic Pole is physically actually a magnetic north pole (see also North Magnetic Pole – Polarity).
The South Magnetic Pole is constantly shifting due to changes in the Earth's magnetic field.
As of 2005 it was calculated to lie at 64°31′48"S 137°51′36"E, just off the coast of Adelie Land
Adélie Land
Adélie Land is the portion of the Antarctic coast between 136° E and 142° E , with a shore length of 350 km and with its hinterland extending as a sector about 2,600 km toward the South Pole. It is claimed by France as one of five districts of the French Southern and Antarctic Lands, although not...
, French Antarctica. That point lies outside the Antarctic Circle
Antarctic Circle
The Antarctic Circle is one of the five major circles of latitude that mark maps of the Earth. For 2011, it is the parallel of latitude that runs south of the Equator.-Description:...
. Due to polar drift
Polar drift
Polar drift is a geological phenomenon caused by variations in the flow of molten iron in Earth's outer core, resulting in changes in the orientation of Earth's magnetic field, and hence the position of the magnetic north pole....
, the pole is moving north west by about 10 to 15 kilometers per year.
| North Magnetic Pole | (2001) 81.3°N 110.8°W | (2004 est) 82.3°N 113.4°W | (2005 est) 82.7°N 114.4°W |
| South Magnetic Pole | (1998) 64.6°S 138.5°E | (2004 est) 63.5°S 138.0°E | (2007) 64.497°S 137.684°E |
Expeditions
Early unsuccessful attempts to reach the South Magnetic Pole included those of French explorer Dumont d'Urville (1840), American Charles WilkesCharles Wilkes
Charles Wilkes was an American naval officer and explorer. He led the United States Exploring Expedition, 1838-1842 and commanded the ship in the Trent Affair during the American Civil War...
(expedition of 1838–42) and Briton James Clark Ross
James Clark Ross
Sir James Clark Ross , was a British naval officer and explorer. He explored the Arctic with his uncle Sir John Ross and Sir William Parry, and later led his own expedition to Antarctica.-Arctic explorer:...
(expedition of 1839–43).
On January 16, 1909 three men (Douglas Mawson
Douglas Mawson
Sir Douglas Mawson, OBE, FRS, FAA was an Australian geologist, Antarctic explorer and Academic. Along with Roald Amundsen, Robert Falcon Scott, and Ernest Shackleton, Mawson was a key expedition leader during the Heroic Age of Antarctic Exploration.-Early work:He was appointed geologist to an...
, Edgeworth David
Edgeworth David
Sir Tannatt William Edgeworth David KBE, DSO, FRS, was a Welsh Australian geologist and Antarctic explorer. A household name in his lifetime, David's most significant achievements were discovering the major Hunter Valley coalfield in New South Wales and leading the first expedition to reach the...
, and Alistair Mackay
Alistair Mackay
Alistair Mackay was a Scottish doctor and polar explorer. He was one the trio of explorers, along with Douglas Mawson and Professor Edgeworth David, who became the first humans to reach the Magnetic South Pole.-Antarctica with Shackleton:...
) from Sir Ernest Shackleton's Nimrod Expedition
Nimrod Expedition
The British Antarctic Expedition 1907–09, otherwise known as the Nimrod Expedition, was the first of three expeditions to the Antarctic led by Ernest Shackleton. Its main target, among a range of geographical and scientific objectives, was to be first to the South Pole...
claimed to have found the South Magnetic Pole, which was at that time located on land. However, there is now some doubt as to whether their location was correct.
The approximate position of the pole on 16 January 1909 was 72.25°S 155.15°E.
Fits to global data sets
The South Magnetic Pole has also been estimated by fits to global sets of data such as the World Magnetic ModelWorld Magnetic Model
The World Magnetic Model is a large spatial-scale representation of the Earth's magnetic field. It consists of a degree and order 12 spherical-harmonic expansion of the magnetic potential of the geomagnetic main field generated in the Earth’s core...
(WMM) and the International Geomagnetic Reference Model
International Geomagnetic Reference Model
The International Geomagnetic Reference Field is a standard mathematical description of the Earth's main magnetic field. It is the product of a collaborative effort between magnetic field modellers and the institutes involved in collecting and disseminating magnetic field data from satellites and...
(IGRF). For earlier years back to about 1600, the model GUFM1 is used, based on a compilation of data from ship logs.
South Geomagnetic Pole
The Earth's geomagnetic field can be approximated by a tilted dipole (like a bar magnet) placed at the center of the Earth. The South Geomagnetic Pole is the point where the axis of this best-fitting tilted dipole intersects the Earth's surface in the southern hemisphere. As of 2005 it was calculated to be located at 79.74°S 108.22°E http://www.ngdc.noaa.gov/geomag/faqgeom.shtml, near the Vostok StationVostok Station
Vostok Station was a Russian Antarctic research station. It was at the southern Pole of Cold, with the lowest reliably measured natural temperature on Earth of −89.2 °C . Research includes ice core drilling and magnetometry...
. 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 magnetic counterpart wanders.