Geographical pole
Encyclopedia
A geographical pole is either of the two points—the north pole
and the south pole
—on the surface of a rotating planet
(or other rotating body) where the axis of rotation (or simply "axis") meets the surface of the body. The north geographic pole of a body lies 90 degrees north of the equator
, while the south geographic pole lies 90 degrees south of the equator.
It is possible for geographical poles to "wander" slightly relative to the surface of a body due to perturbations in rotation. The Earth's actual physical North Pole and South Pole vary cyclically by a few meters over the span of each few years. This phenomenon is distinct from the precession of the equinoxes of the Earth, in which the angle of the planet (both axis and surface, moving together) varies slowly over tens of thousands of years.
As cartography
requires exact and unchanging coordinates, cartographical poles (also cartographic poles) are fixed points on the Earth or another rotating body at the approximate location of the slightly varying geographical poles. These cartographical poles are the points at which the great circle
s of longitude
intersect.
Geographical poles and cartographical poles should not be confused with magnetic pole
s, which can also exist on a planet or other body.
For geographical and cartographical poles on astronomical bodies other than Earth, see Poles of astronomical bodies
.
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...
and the south pole
South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole...
—on the surface of a rotating planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
(or other rotating body) where the axis of rotation (or simply "axis") meets the surface of the body. The north geographic pole of a body lies 90 degrees north of the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
, while the south geographic pole lies 90 degrees south of the equator.
It is possible for geographical poles to "wander" slightly relative to the surface of a body due to perturbations in rotation. The Earth's actual physical North Pole and South Pole vary cyclically by a few meters over the span of each few years. This phenomenon is distinct from the precession of the equinoxes of the Earth, in which the angle of the planet (both axis and surface, moving together) varies slowly over tens of thousands of years.
As cartography
Cartography
Cartography is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.The fundamental problems of traditional cartography are to:*Set the map's...
requires exact and unchanging coordinates, cartographical poles (also cartographic poles) are fixed points on the Earth or another rotating body at the approximate location of the slightly varying geographical poles. These cartographical poles are the points at which the great circle
Great circle
A great circle, also known as a Riemannian circle, of a sphere is the intersection of the sphere and a plane which passes through the center point of the sphere, as opposed to a general circle of a sphere where the plane is not required to pass through the center...
s of longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
intersect.
Geographical poles and cartographical poles should not be confused with magnetic pole
Magnetic pole
Magnetic pole may refer to:* One of the two ends of a magnet* The magnetic poles of astronomical bodies, a special case of magnets, two special cases of which are the Geomagnetic poles:...
s, which can also exist on a planet or other body.
See also
For the geographical and cartographical poles on Earth, see:- North PoleNorth PoleThe North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...
- South PoleSouth PoleThe South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole...
For geographical and cartographical poles on astronomical bodies other than Earth, see Poles of astronomical bodies
Poles of astronomical bodies
The poles of astronomical bodies are determined based on their axis of rotation in relation to the celestial poles of the celestial sphere.-Geographic poles:...
.
- Equatorial bulgeEquatorial bulgeAn equatorial bulge is a difference between the equatorial and polar diameters of a planet, due to the centrifugal force of its rotation. A rotating body tends to form an oblate spheroid rather than a sphere...
- Polar regionPolar regionEarth's polar regions are the areas of the globe surrounding the poles also known as frigid zones. The North Pole and South Pole being the centers, these regions are dominated by the polar ice caps, resting respectively on the Arctic Ocean and the continent of Antarctica...
- AntipodesAntipodesIn geography, the antipodes of any place on Earth is the point on the Earth's surface which is diametrically opposite to it. Two points that are antipodal to one another are connected by a straight line running through the centre of the Earth....