Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in the Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of the Earth's magnetic field at its surface ranges from 25 to 65 μT. As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11 degrees with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of the Earth. The North geomagnetic pole actually represents the South pole of the Earth's magnetic field, and conversely the South geomagnetic pole corresponds to the north pole of Earth's magnetic field. As of 2015, the North geomagnetic pole was located on Ellesmere Island, Nunavut, Canada.
Dakshin Gangotri was the first scientific base station of India situated in Antarctica, part of the Indian Antarctic Programme. It is located at a distance of 2,500 kilometres (1,600 mi) from the South Pole. It is currently being used as a supply base and transit camp. The base is named after Dakshin Gangotri Glacier.
Paleomagnetism, or palaeomagnetism, is the study of the record of the Earth's magnetic field in rocks, sediment, or archeological materials. Magnetic minerals in rocks can lock-in a record of the direction and intensity of the magnetic field when they form. This record provides information on the past behavior of Earth's magnetic field and the past location of tectonic plates. The record of geomagnetic reversals preserved in volcanic and sedimentary rock sequences (magnetostratigraphy) provides a time-scale that is used as a geochronologic tool. Geophysicists who specialize in paleomagnetism are called paleomagnetists.
The cataclysmic pole shift hypothesis suggests that there have been geologically-rapid shifts in the relative positions of the modern-day geographic locations of the poles and the axis of rotation of Earth, causing calamities such as floods and tectonic events.
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.
A geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged. The Earth's field has alternated between periods of normal polarity, in which the predominant direction of the field was the same as the present direction, and reverse polarity, in which it was the opposite. These periods are called chrons.
Ørsted is Denmark's first satellite, named after Hans Christian Ørsted (1777–1851), a Danish physicist and professor at the University of Copenhagen, who discovered electromagnetism in 1820.
Soviet and Russian staffed drifting ice stations are research stations built on the ice of the high latitudes of the Arctic Ocean. They are important contributors to exploration of the Arctic. The stations are named North Pole, followed by an ordinal number: North Pole-1, etc.
In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying material. The magnetic variation in successive bands of ocean floor parallel with mid-ocean ridges was important evidence for seafloor spreading, a concept central to the theory of plate tectonics.
True polar wander is a solid-body rotation of a planet or moon with respect to its spin axis, causing the geographic locations of the north and south poles to change, or "wander". If a body is not totally rigid, then in a stable state, the largest moment of inertia axis will be aligned with the spin axis, with the smaller two moments of inertia axes lying in the plane of the equator. If the body is not in this steady state, true polar wander will occur: the planet or moon will rotate as a rigid body to realign the largest moment of inertia axis with the spin axis.
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of Earth and lies on the opposite side of Earth from the North Pole.
Swarm is a European Space Agency (ESA) mission to study the Earth's magnetic field. High-precision and high-resolution measurements of the strength, direction and variations of the Earth's magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide data for modelling the geomagnetic field and its interaction with other physical aspects of the Earth system. The results offer a view of the inside of the Earth from space, enabling the composition and processes of the interior to be studied in detail and increase our knowledge of atmospheric processes and ocean circulation patterns that affect climate and weather.
Geomagnetic secular variation refers to changes in the Earth's magnetic field on time scales of about a year or more. These changes mostly reflect changes in the Earth's interior, while more rapid changes mostly originate in the ionosphere or magnetosphere.
Plate reconstruction is the process of reconstructing the positions of tectonic plates relative to each other or to other reference frames, such as the earth's magnetic field or groups of hotspots, in the geological past. This helps determine the shape and make-up of ancient supercontinents and provides a basis for paleogeographic reconstructions.
The north magnetic pole is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downward. There is only one location where this occurs, near the geographic north pole. The geomagnetic north pole, a related point, is the pole of an ideal dipole model of the Earth's magnetic field that most closely fits the Earth's actual magnetic field.
The south magnetic pole is the point on Earth's Southern Hemisphere where the geomagnetic field lines are directed vertically upwards. The Geomagnetic South Pole, a related point, is the south pole of an ideal dipole model of the Earth's magnetic field that most closely fits the Earth's actual magnetic field.
The geomagnetic poles are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth. This theoretical dipole is equivalent to a powerful bar magnet at the center of Earth, and comes closer than any other model to describing the magnetic field observed at Earth's surface. In contrast, the magnetic poles of the actual Earth are not antipodal; that is, the line on which they lie does not pass through Earth's center.
The following outline is provided as an overview of and topical guide to geophysics:
The South Pole–Queen Maud Land Traverse (SPQMLT) was a three-part scientific exploration of Antarctica undertaken by the United States in the 1960s. The three parts, referred to individually as South Pole–Queen Maud Land Traverse I, II, and III, traveled a zigzag route across nearly 4200 km of the Antarctic Plateau in the austral summers of 1964–1965, 1965–1966, and 1967–1968. The participants included scientists from Belgium, Norway, and the United States. Their objectives included determining the thickness of the Antarctic Ice Sheet, the elevation and slope of its surface, the rate of ice accumulation, and the subglacial topography. Other objectives included measuring the density and temperature of the ice at depth, measuring the geomagnetic field and gravity, and obtaining snow samples and ice cores.
A space hurricane is a huge, funnel-like, spiral geomagnetic storm that occurs above the polar Ionosphere of Earth, during extremely quiet conditions. They are related to the aurora borealis phenomenon, as the electron precipitation from the storm's funnel produces gigantic, cyclone-shaped auroras. Scientists believe that they occur in the polar regions of planets with magnetic fields.
