HOME

TheInfoList



OR:

The north magnetic pole, also known as the magnetic north pole, is a point on the surface of Earth's
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
at which the planet's magnetic field points vertically downward (in other words, if a magnetic compass needle is allowed to rotate in three dimensions, it will point straight down). There is only one location where this occurs, near (but distinct from) the geographic
north pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Ma ...
. 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 in the
Earth's outer core Earth's outer core is a fluid layer about thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. The outer core begins approximately beneath Earth's surface at the core-mantle boundary and e ...
. In 2001, it was determined by the
Geological Survey of Canada The Geological Survey of Canada (GSC; french: Commission géologique du Canada (CGC)) is a Canadian federal government agency responsible for performing geological surveys of the country, developing Canada's natural resources and protecting the e ...
to lie west of
Ellesmere Island Ellesmere Island ( iu, script=Latn, Umingmak Nuna, lit=land of muskoxen; french: île d'Ellesmere) is Canada's northernmost and third largest island, and the tenth largest in the world. It comprises an area of , slightly smaller than Great Br ...
in
northern Canada Northern Canada, colloquially the North or the Territories, is the vast northernmost region of Canada variously defined by geography and politics. Politically, the term refers to the three territories of Canada: Yukon, Northwest Territories an ...
at . It was situated at in 2005. In 2009, while still situated within the Canadian
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
at , it was moving toward Russia at between per year. As of 2021, the pole is projected to have moved beyond the Canadian Arctic to . Its southern hemisphere counterpart is the south magnetic pole. Since Earth's magnetic field is not exactly symmetric, the north and south magnetic poles are not antipodal, meaning that a straight line drawn from one to the other does not pass through the geometric center of Earth. Earth's north and south magnetic poles are also known as '' magnetic dip poles'', with reference to the vertical "dip" of the magnetic field lines at those points.


Polarity

All
magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nicke ...
s have two poles, where the lines of
magnetic flux In physics, specifically electromagnetism, the magnetic flux through a surface is the surface integral of the normal component of the magnetic field B over that surface. It is usually denoted or . The SI unit of magnetic flux is the weber ...
enter and emerge. By analogy with Earth's magnetic field, these are called the magnet's "north" and "south" poles. The north-seeking pole of a magnet was defined to have the north designation, according to their use in early
compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...
es. Because opposite poles attract, this means that as a physical magnet, the magnetic north pole of the earth is actually on the southern hemisphere. The direction of magnetic field lines is defined such that the lines emerge from the magnet's north pole and enter into the magnet's south pole.


History

Early European navigators, cartographers and scientists believed that compass needles were attracted to a hypothetical "magnetic island" somewhere in the far north (see Rupes Nigra), or to
Polaris Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris ( Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude th ...
, the
pole star A pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body. Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude-2 star aligned approximately with its ...
.Early Concept of the North Magnetic Pole
Natural Resources Canada, retrieved June 2007
The idea that Earth itself acts as essentially a giant magnet was first proposed in 1600, by the English physician and natural philosopher William Gilbert. He was also the first to define the north magnetic pole as the point where Earth's magnetic field points vertically downwards. This is the current definition, though it would be a few hundred years before the nature of Earth's magnetic field was understood with modern accuracy and precision.


Expeditions and measurements


First observations

The first group to reach the north magnetic pole was led by
James Clark Ross Sir James Clark Ross (15 April 1800 – 3 April 1862) was a British Royal Navy officer and polar explorer known for his explorations of the Arctic, participating in two expeditions led by his uncle John Ross, and four led by William Edwa ...
, who found it at Cape Adelaide on the
Boothia Peninsula Boothia Peninsula (; formerly ''Boothia Felix'', Inuktitut ''Kingngailap Nunanga'') is a large peninsula in Nunavut's northern Canadian Arctic, south of Somerset Island. The northern part, Murchison Promontory, is the northernmost point of ...
on June 1, 1831, while serving on the second arctic expedition of his uncle, Sir John Ross.
Roald Amundsen Roald Engelbregt Gravning Amundsen (, ; ; 16 July 1872 – ) was a Norwegian explorer of polar regions. He was a key figure of the period known as the Heroic Age of Antarctic Exploration. Born in Borge, Østfold, Norway, Amundsen beg ...
found the north magnetic pole in a slightly different location in 1903. The third observation was by Canadian government scientists Paul Serson and Jack Clark, of the Dominion Astrophysical Observatory, who found the pole at Allen Lake on Prince of Wales Island in 1947.


Project Polaris

At the start of the
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because t ...
, the
United States Department of War The United States Department of War, also called the War Department (and occasionally War Office in the early years), was the United States Cabinet department originally responsible for the operation and maintenance of the United States Army, ...
recognized a need for a comprehensive survey of the North American
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
and asked the
United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, ...
to undertake the task. An assignment was made in 1946 for the newly formed Army's Air Corps
Strategic Air Command Strategic Air Command (SAC) was both a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile ...
to explore the entire
Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...
area. The exploration was conducted by the 46th (later re-designated the 72nd) Photo Reconnaissance Squadron and reported on as a classified ''Top Secret'' mission named Project Nanook. This project in turn was divided into many separate, but identically classified, projects, one of which was Project Polaris, which was a radar, photographic ( trimetrogon, or three-angle, cameras) and visual study of the entire Canadian Archipelago. A Canadian officer observer was assigned to accompany each flight. Frank O. Klein, the director of the project, noticed that the
fluxgate compass The basic fluxgate compass is a simple electromagnetic device that employs two or more small coils of wire around a core of highly permeable magnetic material, to directly sense the direction of the horizontal component of the Earth's magnetic fie ...
did not behave as erratically as expected—it oscillated no more than 1 to 2 degrees over much of the region—and began to study northern terrestrial magnetism. With the cooperation of many of his squadron teammates in obtaining many hundreds of statistical readings, startling results were revealed: The center of the north magnetic dip pole was on Prince of Wales Island some NNW of the positions determined by Amundsen and Ross, and the dip pole was not a point but occupied an elliptical region with foci about apart on
Boothia Peninsula Boothia Peninsula (; formerly ''Boothia Felix'', Inuktitut ''Kingngailap Nunanga'') is a large peninsula in Nunavut's northern Canadian Arctic, south of Somerset Island. The northern part, Murchison Promontory, is the northernmost point of ...
and Bathurst Island. Klein called the two foci local poles, for their importance to navigation in emergencies when using a "homing" procedure. About three months after Klein's findings were officially reported, a Canadian ground expedition was sent into the Archipelago to locate the position of the magnetic pole. R. Glenn Madill, Chief of Terrestrial Magnetism,
Department of Mines and Resources Natural Resources Canada (NRCan; french: Ressources naturelles Canada; french: RNCan, label=none)Natural Resources Canada is the applied title under the Federal Identity Program; the legal title is Department of Natural Resources (). is the dep ...
, Canada, wrote to Lt. Klein on 21 July 1948: (The positions were less than apart.)


Modern (post-1996)

The Canadian government has made several measurements since, which show that the north magnetic pole is moving continually northwestward. In 2001, an expedition located the pole at . In 2007, the latest survey found the pole at .L. R. Newitt, A. Chulliat, and J.-J. Orgeval
Location of the north magnetic pole in April 2007
Earth Planets Space, 61, 703–710, 2009
During the 20th century it moved , and since 1970 its rate of motion has accelerated from per year (2001–2007 average; see also polar drift). Members of the 2007 expedition to locate the magnetic north pole wrote that such expeditions have become logistically difficult, as the pole moves farther away from inhabited locations. They expect that in the future, the magnetic pole position will be obtained from satellite data instead of ground surveys. This general movement is in addition to a daily or ''diurnal'' variation in which the north magnetic pole describes a rough ellipse, with a maximum deviation of from its mean position. This effect is due to disturbances of the geomagnetic field by
charged particle In physics, a charged particle is a particle with an electric charge. It may be an ion, such as a molecule or atom with a surplus or deficit of electrons relative to protons. It can also be an electron or a proton, or another elementary pa ...
s from the Sun. As of early 2019, the magnetic north pole is moving from Canada towards Siberia at a rate of approximately per year.


Exploration

The first team of novices to reach the magnetic north pole did so in 1996, led by
David Hempleman-Adams Sir David Kim Hempleman-Adams, (born 10 October 1956 in Swindon, Wiltshire) is an English industrialist and adventurer. He is the first person to complete the Adventurers Grand Slam, by reaching the Geographic and Magnetic North and South Po ...
. It included the first British woman Sue Stockdale and first Swedish woman to reach the Pole. The team also successfully tracked the location of the Magnetic North Pole on behalf of the
University of Ottawa The University of Ottawa (french: Université d'Ottawa), often referred to as uOttawa or U of O, is a bilingual public research university in Ottawa, Ontario, Canada. The main campus is located on directly to the northeast of Downtown Ottaw ...
, and certified its location by
magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, ...
and
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and ...
at . The Polar Race was a biannual competition that ran from 2003 until 2011. It took place between the community of Resolute, on the shores of
Resolute Bay Resolute Bay is an Arctic waterway in the Qikiqtaaluk Region, Nunavut, Canada. It is located in Parry Channel on the southern side of Cornwallis Island. The hamlet of Resolute is located on the northern shore of the bay with Resolute Bay Airpo ...
,
Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the '' Nunavut Act'' and the '' Nunavut Land Claims Agreement Act'' ...
, in
northern Canada Northern Canada, colloquially the North or the Territories, is the vast northernmost region of Canada variously defined by geography and politics. Politically, the term refers to the three territories of Canada: Yukon, Northwest Territories an ...
and the 1996 location of the north magnetic pole at , also in northern Canada. On 25 July 2007, the '' Top Gear: Polar Special'' was broadcast on
BBC Two BBC Two is a British free-to-air public broadcast television network owned and operated by the BBC. It covers a wide range of subject matter, with a remit "to broadcast programmes of depth and substance" in contrast to the more mainstream a ...
in the United Kingdom, in which
Jeremy Clarkson Jeremy Charles Robert Clarkson (born 11 April 1960) is an English broadcaster, journalist, game show host and writer who specialises in motoring. He is best known for the motoring programmes '' Top Gear'' and '' The Grand Tour'' alongside R ...
,
James May James Daniel May (born 16 January 1963) is an English television presenter and journalist. He is best known as a co-presenter of the motoring programme '' Top Gear'' alongside Jeremy Clarkson and Richard Hammond from 2003 until 2015. He also ...
, and their support and camera team claimed to be the first people in history to reach the 1996 location of the north magnetic pole in northern Canada by car. Note that they did not reach the actual north magnetic pole, which at the time (2007) had moved several hundred kilometers further north from the 1996 position.


Magnetic north and magnetic declination

Historically, the magnetic
compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...
was an important tool for
navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation ...
. While it has been widely replaced by
Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite ...
s, many airplanes and ships still carry them, as do casual boaters and hikers. The direction in which a compass needle points is known as magnetic north. In general, this is not exactly the direction of the north magnetic pole (or of any other consistent location). Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over Earth's surface, as well as over time. The local angular difference between magnetic north and
true north True north (also called geodetic north or geographic north) is the direction along Earth's surface towards the geographic North Pole or True North Pole. Geodetic north differs from ''magnetic'' north (the direction a compass points toward t ...
is called the
magnetic declination Magnetic declination, or magnetic variation, is the angle on the horizontal plane between magnetic north (the direction the north end of a magnetized compass needle points, corresponding to the direction of the Earth's magnetic field lines) an ...
. Most map coordinate systems are based on true north, and magnetic declination is often shown on map legends so that the direction of true north can be determined from north as indicated by a compass. In North America the line of zero declination (the ''agonic line'') runs from the north magnetic pole down through
Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...
and southward into the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...
(see figure). Along this line, true north is the same as magnetic north. West of the agonic line a compass will give a reading that is east of true north and by convention the magnetic declination is positive. Conversely, east of the agonic line a compass will point west of true north and the declination is negative.


North geomagnetic pole

As a first-order approximation, Earth's magnetic field can be modeled as a simple
dipole In physics, a dipole () is an electromagnetic phenomenon which occurs in two ways: *An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system ...
(like a bar magnet), tilted about 10° with respect to
Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar star Po ...
axis (which defines the geographic north and geographic south poles) and centered at Earth's center. The north and south geomagnetic poles are the
antipodal point In mathematics, antipodal points of a sphere are those diametrically opposite to each other (the specific qualities of such a definition are that a line drawn from the one to the other passes through the center of the sphere so forms a true d ...
s where the axis of this theoretical dipole intersects Earth's surface. If Earth's magnetic field were a perfect dipole then the
field line A field line is a graphical visual aid for visualizing vector fields. It consists of an imaginary directed line which is tangent to the field vector at each point along its length. A diagram showing a representative set of neighboring field ...
s would be vertical at the geomagnetic poles, and they would coincide with the magnetic poles. However, the approximation is imperfect, and so the magnetic and geomagnetic poles lie some distance apart. Like the north magnetic pole, the north geomagnetic pole attracts the north pole of a bar
magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nicke ...
and so is in a physical sense actually a magnetic ''south'' pole. It is the center of the region of the
magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior d ...
in which the
Aurora Borealis An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of bri ...
can be seen. As of 2015 it was located at approximately , over
Ellesmere Island Ellesmere Island ( iu, script=Latn, Umingmak Nuna, lit=land of muskoxen; french: île d'Ellesmere) is Canada's northernmost and third largest island, and the tenth largest in the world. It comprises an area of , slightly smaller than Great Br ...
, Canada but it is now drifting away from North America and toward Siberia.


Geomagnetic reversal

Over the life of Earth, the orientation of Earth's magnetic field has reversed many times, with magnetic north becoming magnetic south and vice versa – an event known as a
geomagnetic reversal A geomagnetic reversal is a change in a planet's 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 field has alternate ...
. Evidence of geomagnetic reversals can be seen at
mid-ocean ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a div ...
s where
tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
s move apart and the seabed is filled in with
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natura ...
. As the magma seeps out of the
mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...
, cools, and solidifies into igneous rock, it is imprinted with a record of the direction of the magnetic field at the time that the magma cooled.


See also

* Polar alignment


References


External links

* *
Map of pole's wandering
* * * {{Portal bar, Earth sciences, Weather, Astronomy, Stars, Solar System, Science Polar regions of the Earth Geography of the Arctic Geomagnetism Geology of the Arctic Geography of the Northwest Territories Orientation (geometry)