Instruct: Given a question, retrieve passages that can help answer the question.
Query: Which is colder North Pole or South Pole?
The South Pole is at an altitude of 9,300 feet (2,800m) but feels like 11,000 feet (3,400m).[29]. Centrifugal force from the spin of the planet pulls the atmosphere toward the equator. The South Pole is colder than the North Pole because of the elevation difference.[30] The North Pole is a few feet from sea level.
If the brush axis is displaced at an angle to the magnetic axis, a net voltage is induced at the brush terminals which will produce current in the armature. The current in the armature circuit will produce its own magnetic field, with North and South poles, but in this condition, the North Pole is not directly under the North pole of the magnetic axis and the South Pole is not directly above the South Pole of the magnetic axis. The poles of the armature are slightly displaced from those of the stator. In this condition, the N-pole of the stator field will repel the N-pole of the rotor field and the S-pole of stator field will repel the S-pole of the rotor field, so the rotor starts rotating.
Surprisingly, if you run through the path twice, i.e., run from north pole down to south pole, jump back to the north pole (using the fact that north and south poles are identified), and then again run from north pole down to south pole, so that "φ" runs from 0 to 4, you get a closed loop which "can" be shrunk to a single point: first move the paths continuously to the ball's surface, still connecting north pole to south pole twice. The second half of the path can then be mirrored over to the antipodal side without changing the path at all. Now we have an ordinary closed loop on the surface of the ball, connecting the north pole to itself along a great circle. This circle can be shrunk to the north pole without problems. The Balinese plate trick and similar tricks demonstrate this practically.
All magnets have two poles, where the lines of magnetic flux enter and emerge. By analogy with the Earth's magnetic field, these are called the magnet's "north" and "south" poles. The convention in early compasses was to call the end of the needle pointing to the Earth's North Magnetic Pole the "north pole" (or "north-seeking pole") and the other end the "south pole" (the names are often abbreviated to "N" and "S"). Because opposite poles attract, this definition means that the Earth's North Magnetic Pole is actually a magnetic "south" pole and the Earth's South Magnetic Pole is a magnetic "north" pole.
Earth’s magnetic fields are used for migration for a wide variety of species including bacteria, mollusks, arthropods, mammals, birds, reptiles, and amphibians. In order to understand the Earth’s magnetic fields, the earth can be viewed as a large magnet. As a typical magnet has a north and south end, so does the earth. The north pole magnet is located at the Earth’s north pole and the south pole magnet is located at the Earth’s south pole. From this north and south pole span magnetic fields. The magnetic field leaves the poles and curves around the earth until it reaches the opposite pole.
Like the North Magnetic Pole, the North Geomagnetic Pole attracts the north pole of a bar magnet and so is in a physical sense actually a magnetic "south" pole. It is the centre of the region of the magnetosphere in which the Aurora Borealis can be seen. As of 2015 it was located at approximately , over Ellesmere Island, Canada but it is now drifting away from North America and toward Siberia.
Distribution in the mesosphere is similar to the stratosphere except at much higher altitudes. Because of the need for maximum cooling of the water vapor to produce noctilucent clouds, their distribution tends to be restricted to polar regions of Earth. A major seasonal difference is that convective lift from below the mesosphere pushes very scarce water vapor to higher colder altitudes required for cloud formation during the respective summer seasons in the northern and southern hemispheres. Sightings are rare more than 45 degrees south of the north pole or north of the south pole.[126]
Surprisingly, if you run through the path twice, i.e., from north pole down to south pole and back to the north pole so that φ runs from 0 to 4π, you get a closed loop which "can" be shrunk to a single point: first move the paths continuously to the ball's surface, still connecting north pole to south pole twice. The second half of the path can then be mirrored over to the antipodal side without changing the path at all. Now we have an ordinary closed loop on the surface of the ball, connecting the north pole to itself along a great circle. This circle can be shrunk to the north pole without problems. The Balinese plate trick and similar tricks demonstrate this practically.
Philips has completed ski expeditions across icecaps on Greenland, Ellesmere Island, Iceland, Svalbard and Patagonia icecaps and was the first Australian, together with companion Jon Muir, to ski to both the North Pole and South Pole. Philips skied to the North Pole from Siberia in 2002, producing a film, "Icetrek North Pole", and has since guided numerous commercial North Pole expeditions, including the North Pole to Canada leg of Pat Farmer's Pole to Pole Run in 2011.
The north pole of a magnet is defined as the pole that, when the magnet is freely suspended, points towards the Earth's North Magnetic Pole in the Arctic (the magnetic and geographic poles do not coincide, see magnetic declination). Since opposite poles (north and south) attract, the North Magnetic Pole is actually the south pole of the Earth's magnetic field.[15][16][17][18] As a practical matter, to tell which pole of a magnet is north and which is south, it is not necessary to use the Earth's magnetic field at all. For example, one method would be to compare it to an electromagnet, whose poles can be identified by the right-hand rule. The magnetic field lines of a magnet are considered by convention to emerge from the magnet's north pole and reenter at the south pole.[18]
The Earth has a magnetic field which is approximately aligned with its axis of rotation. A magnetic compass is a device that uses this field to determine the cardinal directions. Magnetic compasses are widely used, but only moderately accurate. The north pole of the magnetic needle points towards the geographic north pole of the earth and vice versa. This is because the geographic north pole of the earth lies very close to the magnetic south pole of the earth. This south magnetic pole of the earth located at an angle of 17 degrees to the geographic north pole attracts the north pole of the magnetic needle and vice versa.
As a first-order approximation, the Earth's magnetic field can be modeled as a simple dipole (like a bar magnet), tilted about 9.6° with respect to the Earth's rotation axis (which defines the Geographic North and Geographic South Poles) and centered at the Earth's center. The North and South Geomagnetic Poles are the antipodal points where the axis of this theoretical dipole intersects the Earth's surface, thus unlike the magnetic poles they always have an equal degree of latitude and supplementary degrees of longitude respectively (2017: Lat. 80.5°N, 80.5°S; Long. 72.8°W, 107.2°E). If the Earth's magnetic field were a perfect dipole then the field lines would be vertical to the surface at the Geomagnetic Poles, and they would coincide with the North and South magnetic poles. However, the approximation is imperfect, and so the Magnetic and Geomagnetic Poles lie some distance apart.
Although for many purposes it is convenient to think of a magnet as having distinct north and south magnetic poles, the concept of poles should not be taken literally: it is merely a way of referring to the two different ends of a magnet. The magnet does not have distinct north or south particles on opposing sides. If a bar magnet is broken into two pieces, in an attempt to separate the north and south poles, the result will be two bar magnets, each of which has both a north and south pole. However, a version of the magnetic-pole approach is used by professional magneticians to design permanent magnets.
In the temperate and polar regions, seasons are marked by changes in the amount of sunlight, which in turn often causes cycles of dormancy in plants and hibernation in animals. These effects vary with latitude and with proximity to bodies of water. For example, the South Pole is in the middle of the continent of Antarctica and therefore a considerable distance from the moderating influence of the southern oceans. The North Pole is in the Arctic Ocean, and thus its temperature extremes are buffered by the water. The result is that the South Pole is consistently colder during the southern winter than the North Pole during the northern winter.
Winter temperatures at the northernmost weather station in Greenland can range from about , averaging around , with the North Pole being slightly colder. However, a freak storm caused the temperature to reach for a time at a World Meteorological Organization buoy, located at 87.45°N, on December 30, 2015. It was estimated that the temperature at the North Pole was between during the storm. Summer temperatures (June, July, and August) average around the freezing point (). The highest temperature yet recorded is , much warmer than the South Pole's record high of only . A similar spike in temperatures occurred on November 15, 2016 when temperatures hit freezing. Yet again, February 2018 featured a storm so powerful that temperatures at Cape Morris Jesup, the world's northernmost weather station in Greenland, reached and spent 24 straight hours above freezing. Meanwhile, the pole itself was estimated to reach a high temperature of . This same temperature of was also recorded at the Hollywood Burbank Airport in Los Angeles at the very same time.
The north and south celestial poles are the two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the celestial sphere. The north and south celestial poles appear permanently directly overhead to an observer at the Earth's North Pole and South Pole, respectively. As the Earth spins on its axis, the two celestial poles remain fixed in the sky, and all other points appear to rotate around them, completing one circuit per day (strictly, per sidereal day).
Above is a pole-to-pole view of Martian topography from the first MOLA global topographic model [Smith et al., Science, 1999]. The slice runs from the north pole (left) to the south pole (right) along the 0° longitude line. The figure highlights the pole-to-pole slope of 0.036°, such that the south pole has a higher elevation than the north pole from NASA Goddard Flight Center web site.
In 2009 the responsible IAU Working Group decided to define the poles of dwarf planets, minor planets, their satellites, and comets according to the right-hand rule. To avoid confusion with the "north" and "south" definitions relative to the invariable plane, the poles are called "positive" and "negative." The positive pole is the pole toward which the thumb points when the fingers of the right hand are curled in its direction of rotation. The negative pole is the pole toward which the thumb points when the fingers of the left hand are curled in its direction of rotation. This change was needed because the poles of some asteroids and comets precess rapidly enough for their north and south poles to swap within a few decades using the invariable plane definition.
While the South Pole lies on a continental land mass, the North Pole is located in the middle of the Arctic Ocean amid waters that are almost permanently covered with constantly shifting sea ice. This makes it impractical to construct a permanent station at the North Pole (unlike the South Pole). However, the Soviet Union, and later Russia, constructed a number of manned drifting stations on a generally annual basis since 1937, some of which have passed over or very close to the Pole. Since 2002, the Russians have also annually established a base, Barneo, close to the Pole. This operates for a few weeks during early spring. Studies in the 2000s predicted that the North Pole may become seasonally ice-free because of Arctic ice shrinkage, with timescales varying from 2016 to the late 21st century or later.
As a first-order approximation, the Earth's magnetic field can be modelled as a simple dipole (like a bar magnet), tilted about 10° with respect to the Earth's rotation axis (which defines the Geographic North and Geographic South Poles) and centred at the Earth's centre. The North and South Geomagnetic Poles are the antipodal points where the axis of this theoretical dipole intersects the Earth's surface. If the Earth's magnetic field were a perfect dipole then the field lines 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.
Planetary magnetic poles are defined analogously to the Earth's North and South magnetic poles: they are the locations on the planet's surface at which the planet's magnetic field lines are vertical. The direction of the field determines whether the pole is a magnetic north or south pole, exactly as on Earth. The Earth's magnetic axis is approximately aligned with its rotational axis, meaning that the geomagnetic poles are relatively close to the geographic poles. However, this is not necessarily the case for other planets; the magnetic axis of Uranus, for example, is inclined by as much as 60°.
Historically, the north and south poles of a magnet were first defined by the Earth's magnetic field, not vice versa, since one of the first uses for a magnet was as a compass needle. A magnet's North pole is defined as the pole that is attracted by the Earth's North Magnetic Pole when the magnet is suspended so it can turn freely. Since opposite poles attract, the North Magnetic Pole of the Earth is really the south pole of its magnetic field (the place where the field is directed downward into the Earth).[17][18][19][20]
The H-field, therefore, is analogous to the electric field E, which starts at a positive electric charge and ends at a negative electric charge. Near the north pole, therefore, all H-field lines point away from the north pole (whether inside the magnet or out) while near the south pole all H-field lines point toward the south pole (whether inside the magnet or out). Too, a north pole feels a force in the direction of the H-field while the force on the south pole is opposite to the H-field.
The geographic coordinates of the South Pole are usually given simply as 90°S, since its longitude is geometrically undefined and irrelevant. When a longitude is desired, it may be given as 0°. At the South Pole, all directions face north. For this reason, directions at the Pole are given relative to "grid north", which points northwards along the prime meridian.[1] Along tight latitude circles, clockwise is east, and counterclockwise is west, opposite to the North Pole.
In addition to current loops, the electron, among other fundamental particles, has a magnetic dipole moment. That is because it generates a magnetic field that is identical to that generated by a very small current loop. However, the electron's magnetic moment is not due to a current loop, but is instead an intrinsic property of the electron. It is also possible that the electron has an "electric" dipole moment although it has not yet been observed (see electron electric dipole moment for more information).
A permanent magnet, such as a bar magnet, owes its magnetism to the intrinsic magnetic dipole moment of the electron. The two ends of a bar magnet are referred to as poles (not to be confused with monopoles), and may be labeled "north" and "south". In terms of the Earth's magnetic field, they are respectively "north-seeking" and "south-seeking" poles: if the magnet were freely suspended in the Earth's magnetic field, the north-seeking pole would point towards the north and the south-seeking pole would point towards the south. The dipole moment of the bar magnet points from its magnetic south to its magnetic north pole. The north pole of a bar magnet in a compass points north. However, that means that Earth's geomagnetic north pole is the "south" pole (south-seeking pole) of its dipole moment and vice versa.