Aurora

Images of auroras from across the world, including those with rarer red and blue lights

An aurora^[a] (pl. aurorae or auroras),^[b] also commonly known as the northern lights (aurora borealis) or southern lights (aurora australis),^[c] 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 brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky.^[3]

Auroras are the result of disturbances in the Earth's

Planets in the Solar System, brown dwarfs, comets, and some natural satellites also host auroras.

The term aurora borealis was coined by Galileo Galilei in 1619, from the Roman Aurora, goddess of the dawn, and the Greek Boreas, god of the cold north wind.^[4][5]

The word aurora is derived from the name of the Roman goddess of the dawn,

Aurora borealis was first used to describe the northern lights by the French philosopher, Pierre Gassendi (also called Petrus Gassendus) in 1621, then entered English in 1828.^[6]

Auroras are most commonly observed in the "auroral zone",^[7] a band approximately 6° (~660 km) wide in latitude centered on 67° north and south.^[8] The region that currently displays an aurora is called the "auroral oval". The oval is displaced by the solar wind, pushing it about 15° away from the geomagnetic pole (not the geographic pole) in the noon direction and 23° away in the midnight direction.^[8] The peak equatorward extent of the oval is displaced slightly from geographic midnight. It is centered about 3–5° nightward of the magnetic pole, so that auroral arcs reach furthest toward the equator when the magnetic pole in question is in between the observer and the Sun, which is called magnetic midnight.

Early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis (1860),^[9] and later Hermann Fritz (1881)^[10] and Sophus Tromholt (1881)^[11] in more detail, established that the aurora appeared mainly in the auroral zone.

In northern latitudes, the effect is known as the aurora borealis or the northern lights. The southern counterpart, the aurora australis or the southern lights, has features almost identical to the aurora borealis and changes simultaneously with changes in the northern auroral zone.^[12] The aurora australis is visible from high southern latitudes in Antarctica, the Southern Cone, South Africa, Australasia, the Falkland Islands, and under exceptional circumstances as far north as Uruguay.^[13] The aurora borealis is visible from areas around the Arctic such as Alaska, Canada, Iceland, Greenland, the Faroe Islands, Scandinavia, Finland, Scotland, and Russia. A geomagnetic storm causes the auroral ovals (north and south) to expand, bringing the aurora to lower latitudes. On rare occasions, the aurora borealis can be seen as far south as the Mediterranean and the southern states of the US while the aurora australis can be seen as far north as New Caledonia and the Pilbara region in Western Australia. During the Carrington Event, the greatest geomagnetic storm ever observed, auroras were seen even in the tropics.

Auroras seen within the auroral oval may be directly overhead. From farther away, they illuminate the poleward horizon as a greenish glow, or sometimes a faint red, as if the Sun were rising from an unusual direction. Auroras also occur poleward of the auroral zone as either diffuse patches or arcs,^[14] which can be subvisual.

Videos of the aurora australis taken by the crew of Expedition 28 on board the International Space Station

This sequence of shots was taken 17 September 2011 from 17:22:27 to 17:45:12 GMT, on an ascending pass from south of Madagascar to just north of Australia over the Indian Ocean.

This sequence of shots was taken 7 September 2011 from 17:38:03 to 17:49:15 GMT, from the French Southern and Antarctic Lands in the South Indian Ocean to southern Australia.

This sequence of shots was taken 11 September 2011 from 13:45:06 to 14:01:51 GMT, from a descending pass near eastern Australia, rounding about to an ascending pass to the east of New Zealand.

NOAA maps of North America and Eurasia

North America

Eurasia

These maps show the local midnight equatorward boundary of the aurora at different levels of geomagnetic activity as of 28 October 2011 – these maps change as the location of the geomagnetic poles change. A K-index of K_p= 3 corresponds to relatively low levels of geomagnetic activity, while K_p= 9 represents high levels.

Auroras are occasionally seen in latitudes below the auroral zone, when a geomagnetic storm temporarily enlarges the auroral oval. Large geomagnetic storms are most common during the peak of the 11-year sunspot cycle or during the three years after the peak.^[15][16] An electron spirals (gyrates) about a field line at an angle that is determined by its velocity vectors, parallel and perpendicular, respectively, to the local geomagnetic field vector B. This angle is known as the "pitch angle" of the particle. The distance, or radius, of the electron from the field line at any time is known as its Larmor radius. The pitch angle increases as the electron travels to a region of greater field strength nearer to the atmosphere. Thus, it is possible for some particles to return, or mirror, if the angle becomes 90° before entering the atmosphere to collide with the denser molecules there. Other particles that do not mirror enter the atmosphere and contribute to the auroral display over a range of altitudes. Other types of auroras have been observed from space; for example, "poleward arcs" stretching sunward across the polar cap, the related "theta aurora",^[17] and "dayside arcs" near noon. These are relatively infrequent and poorly understood. Other interesting effects occur such as pulsating aurora, "black aurora" and their rarer companion "anti-black aurora" and subvisual red arcs. In addition to all these, a weak glow (often deep red) observed around the two polar cusps, the field lines separating the ones that close through Earth from those that are swept into the tail and close remotely.

Early work on the imaging of the auroras was done in 1949 by the University of Saskatchewan using the SCR-270 radar.^[18] The altitudes where auroral emissions occur were revealed by Carl Størmer and his colleagues, who used cameras to triangulate more than 12,000 auroras.^[19] They discovered that most of the light is produced between 90 and 150 km (56 and 93 mi) above the ground, while extending at times to more than 1,000 km (620 mi).

According to Clark (2007), there are five main forms that can be seen from the ground, from least to most visible:^[20]

• A mild glow, near the horizon. These can be close to the limit of visibility,^[21] but can be distinguished from moonlit clouds because stars can be seen undiminished through the glow.
• Patches or surfaces that look like clouds.
• Arcs curve across the sky.
• Rays are light and dark stripes across arcs, reaching upwards by various amounts.
• Coronas cover much of the sky and diverge from one point on it.

Brekke (1994) also described some auroras as "curtains".^[22] The similarity to curtains is often enhanced by folds within the arcs. Arcs can fragment or break up into separate, at times rapidly changing, often rayed features that may fill the whole sky. These are also known as discrete auroras, which are at times bright enough to read a newspaper by at night.^[23]

These forms are consistent with auroras being shaped by Earth's magnetic field. The appearances of arcs, rays, curtains, and coronas are determined by the shapes of the luminous parts of the atmosphere and a viewer's position.^[24]

• Red: At its highest altitudes, excited atomic oxygen emits at 630 nm (red); low concentration of atoms and lower sensitivity of eyes at this wavelength make this colour visible only under more intense solar activity. The low number of oxygen atoms and their gradually diminishing concentration is responsible for the faint appearance of the top parts of the "curtains". Scarlet, crimson, and carmine are the most often-seen hues of red for the auroras.^{[citation needed]}
• Green: At lower altitudes, the more frequent collisions suppress the 630 nm (red) mode: rather the 557.7 nm emission (green) dominates. A fairly high concentration of atomic oxygen and higher eye sensitivity in green make green auroras the most common. The excited molecular nitrogen (atomic nitrogen being rare due to the high stability of the N₂ molecule) plays a role here, as it can transfer energy by collision to an oxygen atom, which then radiates it away at the green wavelength. (Red and green can also mix together to produce pink or yellow hues.) The rapid decrease of concentration of atomic oxygen below about 100 km is responsible for the abrupt-looking end of the lower edges of the curtains. Both the 557.7 and 630.0 nm wavelengths correspond to
  forbidden transitions of atomic oxygen, a slow mechanism responsible for the graduality (0.7 s and 107 s respectively) of flaring and fading.^{[citation needed}
  ]

• Blue: At yet lower altitudes, atomic oxygen is uncommon, and molecular nitrogen and ionized molecular nitrogen take over in producing visible light emission, radiating at a large number of wavelengths in both red and blue parts of the spectrum, with 428 nm (blue) being dominant. Blue and purple emissions, typically at the lower edges of the "curtains", show up at the highest levels of solar activity.^[25] The molecular nitrogen transitions are much faster than the atomic oxygen ones.
• Ultraviolet: Ultraviolet radiation from auroras (within the optical window but not visible to virtually all^{[clarification needed]} humans) has been observed with the requisite equipment. Ultraviolet auroras have also been seen on Mars,^[26] Jupiter, and Saturn.
• Infrared: Infrared radiation, in wavelengths that are within the optical window, is also part of many auroras.^[26][27]
• Yellow and pink are
  a mix of red and green or blue. Other shades of red, as well as orange and gold, may be seen on rare occasions; yellow-green is moderately common.^{[clarification needed}
  ] As red, green, and blue are linearly independent colours, additive synthesis could, in theory, produce most human-perceived colours, but the ones mentioned in this article comprise a virtually exhaustive list.

Auroras change with time. Over the night they begin with glows and progress toward coronas, although they may not reach them. They tend to fade in the opposite order.

At shorter time scales, auroras can change their appearances and intensity, sometimes so slowly as to be difficult to notice, and at other times rapidly down to the sub-second scale.[23] The phenomenon of pulsating auroras is an example of intensity variations over short timescales, typically with periods of 2–20 seconds. This type of aurora is generally accompanied by decreasing peak emission heights of about 8 km for blue and green emissions and above average solar wind speeds (c. 500 km/s).^[30]

In addition, the aurora and associated currents produce a strong radio emission around 150 kHz known as auroral kilometric radiation (AKR), discovered in 1972.^[31] Ionospheric absorption makes AKR only observable from space. X-ray emissions, originating from the particles associated with auroras, have also been detected.^[32]

Aurora noise, similar to a crackling noise, begins about 70 m (230 ft) above Earth's surface and is caused by charged particles in an inversion layer of the atmosphere formed during a cold night. The charged particles discharge when particles from the Sun hit the inversion layer, creating the noise.^[33][34]

In 2016, more than fifty

The processes that cause STEVE are also associated with a picket-fence aurora, although the latter can be seen without STEVE.[36]^[37] It is an aurora because it is caused by precipitation of electrons in the atmosphere but it appears outside the auroral oval,^[38] closer to the equator than typical auroras.^[39] When the picket-fence aurora appears with STEVE, it is below.^[37]

First reported in 2020,^[40][41] and confirmed in 2021,^[42][43] the dune aurora phenomenon was discovered^[44] by Finnish citizen scientists. It consists of regularly-spaced, parallel stripes of brighter emission in the green diffuse aurora which give the impression of sand dunes.^[45] The phenomenon is believed to be caused by the modulation of atomic oxygen density by a large-scale atmospheric wave travelling horizontally in a waveguide through an inversion layer in the mesosphere in presence of electron precipitation.^[42]

Horse-collar auroras (HCA) are auroral features in which the auroral ellipse shifts poleward during the dawn and dusk portions and the polar cap becomes teardrop-shaped. They form during periods when the interplanetary magnetic field (IMF) is permanently northward, when the IMF clock angle is small. Their formation is associated with the closure of the magnetic flux at the top of the dayside magnetosphere by the double lobe reconnection (DLR). There are approximately 8 HCA events per month, with no seasonal dependence, and that the IMF must be within 30 degrees of northwards.^[46]

Conjugate auroras are nearly exact mirror-image auroras found at conjugate points in the northern and southern hemispheres on the same geomagnetic field lines. These generally happen at the time of the equinoxes, when there is little difference in the orientation of the north and south geomagnetic poles to the sun. Attempts were made to image conjugate auroras by aircraft from Alaska and New Zealand in 1967, 1968, 1970, and 1971, with some success.^[47]

A full understanding of the physical processes which lead to different types of auroras is still incomplete, but the basic cause involves the interaction of the

1. A quiescent solar wind flowing past Earth's magnetosphere steadily interacts with it and can both inject solar wind particles directly onto the geomagnetic field lines that are 'open', as opposed to being 'closed' in the opposite hemisphere and provide diffusion through the bow shock. It can also cause particles already trapped in the radiation belts to precipitate into the atmosphere. Once particles are lost to the atmosphere from the radiation belts, under quiet conditions, new ones replace them only slowly, and the loss-cone becomes depleted. In the magnetotail, however, particle trajectories seem constantly to reshuffle, probably when the particles cross the very weak magnetic field near the equator. As a result, the flow of electrons in that region is nearly the same in all directions ("isotropic") and assures a steady supply of leaking electrons. The leakage of electrons does not leave the tail positively charged, because each leaked electron lost to the atmosphere is replaced by a low energy electron drawn upward from the ionosphere. Such replacement of "hot" electrons by "cold" ones is in complete accord with the second law of thermodynamics. The complete process, which also generates an electric ring current around Earth, is uncertain.
2. Geomagnetic disturbance from an enhanced solar wind causes distortions of the magnetotail ("magnetic substorms"). These 'substorms' tend to occur after prolonged spells (on the order of hours) during which the interplanetary magnetic field has had an appreciable southward component. This leads to a higher rate of interconnection between its field lines and those of Earth. As a result, the solar wind moves magnetic flux (tubes of magnetic field lines, 'locked' together with their resident plasma) from the day side of Earth to the magnetotail, widening the obstacle it presents to the solar wind flow and constricting the tail on the night-side. Ultimately some tail plasma can separate ("magnetic reconnection"); some blobs ("plasmoids") are squeezed downstream and are carried away with the solar wind; others are squeezed toward Earth where their motion feeds strong outbursts of auroras, mainly around midnight ("unloading process"). A geomagnetic storm resulting from greater interaction adds many more particles to the plasma trapped around Earth, also producing enhancement of the "ring current". Occasionally the resulting modification of Earth's magnetic field can be so strong that it produces auroras visible at middle latitudes, on field lines much closer to the equator than those of the auroral zone.

   

3. Acceleration of auroral charged particles invariably accompanies a magnetospheric disturbance that causes an aurora. This mechanism, which is believed to predominantly arise from strong electric fields along the magnetic field or wave-particle interactions, raises the velocity of a particle in the direction of the guiding magnetic field. The pitch angle is thereby decreased and increases the chance of it being precipitated into the atmosphere. Both electromagnetic and electrostatic waves, produced at the time of greater geomagnetic disturbances, make a significant contribution to the energizing processes that sustain an aurora. Particle acceleration provides a complex intermediate process for transferring energy from the solar wind indirectly into the atmosphere.

The details of these phenomena are not fully understood. However, it is clear that the prime source of auroral particles is the solar wind feeding the magnetosphere, the reservoir containing the radiation zones and temporarily magnetically trapped particles confined by the geomagnetic field, coupled with particle acceleration processes.^[48]

The immediate cause of the ionization and excitation of atmospheric constituents leading to auroral emissions was discovered in 1960, when a pioneering rocket flight from Fort Churchill in Canada revealed a flux of electrons entering the atmosphere from above.^[49] Since then an extensive collection of measurements has been acquired painstakingly and with steadily improving resolution since the 1960s by many research teams using rockets and satellites to traverse the auroral zone. The main findings have been that auroral arcs and other bright forms are due to electrons that have been accelerated during the final few 10,000 km or so of their plunge into the atmosphere.^[50] These electrons often, but not always, exhibit a peak in their energy distribution, and are preferentially aligned along the local direction of the magnetic field.

Electrons mainly responsible for diffuse and pulsating auroras have, in contrast, a smoothly falling energy distribution, and an angular (pitch-angle) distribution favouring directions perpendicular to the local magnetic field. Pulsations were discovered to originate at or close to the equatorial crossing point of auroral zone magnetic field lines.^[51] Protons are also associated with auroras, both discrete and diffuse.

Auroras result from emissions of

Oxygen emissions

green or orange-red, depending on the amount of energy absorbed.

Nitrogen emissions

blue, purple or red; blue and purple if the molecule regains an electron after it has been ionized, red if returning to ground state from an excited state.

Oxygen is unusual in terms of its return to ground state: it can take 0.7 seconds to emit the 557.7 nm green light and up to two minutes for the red 630.0 nm emission. Collisions with other atoms or molecules absorb the excitation energy and prevent emission; this process is called collisional quenching. Because the highest parts of the atmosphere contain a higher percentage of oxygen and lower particle densities, such collisions are rare enough to allow time for oxygen to emit red light. Collisions become more frequent progressing down into the atmosphere due to increasing density, so that red emissions do not have time to happen, and eventually, even green light emissions are prevented.

This is why there is a colour differential with altitude; at high altitudes oxygen red dominates, then oxygen green and nitrogen blue/purple/red, then finally nitrogen blue/purple/red when collisions prevent oxygen from emitting anything. Green is the most common colour. Then comes pink, a mixture of light green and red, followed by pure red, then yellow (a mixture of red and green), and finally, pure blue.

Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere. Proton auroras are usually observed at lower latitudes.^[53]

Bright auroras are generally associated with Birkeland currents (Schield et al., 1969;^[54] Zmuda and Armstrong, 1973^[55]), which flow down into the ionosphere on one side of the pole and out on the other. In between, some of the current connects directly through the ionospheric E layer (125 km); the rest ("region 2") detours, leaving again through field lines closer to the equator and closing through the "partial ring current" carried by magnetically trapped plasma. The ionosphere is an ohmic conductor, so some consider that such currents require a driving voltage, which an, as yet unspecified, dynamo mechanism can supply. Electric field probes in orbit above the polar cap suggest voltages of the order of 40,000 volts, rising up to more than 200,000 volts during intense magnetic storms. In another interpretation, the currents are the direct result of electron acceleration into the atmosphere by wave/particle interactions.

Ionospheric resistance has a complex nature, and leads to a secondary

The solar wind and magnetosphere consist of plasma (ionized gas), which conducts electricity. It is well known (since Michael Faraday's work around 1830) that when an electrical conductor is placed within a magnetic field while relative motion occurs in a direction that the conductor cuts across (or is cut by), rather than along, the lines of the magnetic field, an electric current is induced within the conductor. The strength of the current depends on a) the rate of relative motion, b) the strength of the magnetic field, c) the number of conductors ganged together and d) the distance between the conductor and the magnetic field, while the direction of flow is dependent upon the direction of relative motion. Dynamos make use of this basic process ("the dynamo effect"), any and all conductors, solid or otherwise are so affected, including plasmas and other fluids.

The IMF originates on the Sun, linked to the sunspots, and its field lines (lines of force) are dragged out by the solar wind. That alone would tend to line them up in the Sun-Earth direction, but the rotation of the Sun angles them at Earth by about 45 degrees forming a spiral in the ecliptic plane, known as the Parker spiral. The field lines passing Earth are therefore usually linked to those near the western edge ("limb") of the visible Sun at any time.^[59]

The solar wind and the magnetosphere, being two electrically conducting fluids in relative motion, should be able in principle to generate electric currents by dynamo action and impart energy from the flow of the solar wind. However, this process is hampered by the fact that plasmas conduct readily along magnetic field lines, but less readily perpendicular to them. Energy is more effectively transferred by the temporary magnetic connection between the field lines of the solar wind and those of the magnetosphere. Unsurprisingly this process is known as magnetic reconnection. As already mentioned, it happens most readily when the interplanetary field is directed southward, in a similar direction to the geomagnetic field in the inner regions of both the north magnetic pole and south magnetic pole.

Auroras are more frequent and brighter during the intense phase of the solar cycle when

Earth's magnetosphere is shaped by the impact of the solar wind on Earth's magnetic field. This forms an obstacle to the flow, diverting it, at an average distance of about 70,000 km (11 Earth radii or Re),^[61] producing a bow shock 12,000 km to 15,000 km (1.9 to 2.4 Re) further upstream. The width of the magnetosphere abreast of Earth is typically 190,000 km (30 Re), and on the night side a long "magnetotail" of stretched field lines extends to great distances (> 200 Re).

The high latitude magnetosphere is filled with plasma as the solar wind passes Earth. The flow of plasma into the magnetosphere increases with additional turbulence, density, and speed in the solar wind. This flow is favoured by a southward component of the IMF, which can then directly connect to the high latitude geomagnetic field lines.^[62] The flow pattern of magnetospheric plasma is mainly from the magnetotail toward Earth, around Earth and back into the solar wind through the magnetopause on the day-side. In addition to moving perpendicular to Earth's magnetic field, some magnetospheric plasma travels down along Earth's magnetic field lines, gains additional energy and loses it to the atmosphere in the auroral zones. The cusps of the magnetosphere, separating geomagnetic field lines that close through Earth from those that close remotely allow a small amount of solar wind to directly reach the top of the atmosphere, producing an auroral glow.

On 26 February 2008,

Geomagnetic storms that ignite auroras may occur more often during the months around the equinoxes. It is not well understood, but geomagnetic storms may vary with Earth's seasons. Two factors to consider are the tilt of both the solar and Earth's axis to the ecliptic plane. As Earth orbits throughout a year, it experiences an interplanetary magnetic field (IMF) from different latitudes of the Sun, which is tilted at 8 degrees. Similarly, the 23-degree tilt of Earth's axis about which the geomagnetic pole rotates with a diurnal variation changes the daily average angle that the geomagnetic field presents to the incident IMF throughout a year. These factors combined can lead to minor cyclical changes in the detailed way that the IMF links to the magnetosphere. In turn, this affects the average probability of opening a door^{[colloquialism]} through which energy from the solar wind can reach Earth's inner magnetosphere and thereby enhance auroras. Recent evidence in 2021 has shown that individual separate substorms may in fact be correlated networked communities.^[65]

Just as there are many types of aurora, there are many different mechanisms that accelerate auroral particles into the atmosphere. Electron aurora in Earth's auroral zone (i.e. commonly visible aurora) can be split into two main categories with different immediate causes: diffuse and discrete aurora. Diffuse aurora appear relatively structureless to an observer on the ground, with indistinct edges and amorphous forms. Discrete aurora are structured into distinct features with well-defined edges such as arcs, rays and coronas; they also tend to be much brighter than the diffuse aurora.

In both cases, the electrons that eventually cause the aurora start out as electrons trapped by the magnetic field in Earth's

In the case of diffuse auroras, the electron pitch angles are altered by their interaction with various plasma waves. Each interaction is essentially wave-particle scattering; the electron energy after interacting with the wave is similar to its energy before interaction, but the direction of motion is altered. If the final direction of motion after scattering is close to the field line (specifically, if it falls within the loss cone) then the electron will hit the atmosphere. Diffuse auroras are caused by the collective effect of many such scattered electrons hitting the atmosphere. The process is mediated by the plasma waves, which become stronger during periods of high geomagnetic activity, leading to increased diffuse aurora at those times.

In the case of discrete auroras, the trapped electrons are accelerated toward Earth by electric fields that form at an altitude of about 4000–12000 km in the "auroral acceleration region". The electric fields point away from Earth (i.e. upward) along the magnetic field line.^[66] Electrons moving downward through these fields gain a substantial amount of energy (on the order of a few keV) in the direction along the magnetic field line toward Earth. This field-aligned acceleration decreases the pitch angle for all of the electrons passing through the region, causing many of them to hit the upper atmosphere. In contrast to the scattering process leading to diffuse auroras, the electric field increases the kinetic energy of all of the electrons transiting downward through the acceleration region by the same amount. This accelerates electrons starting from the magnetosphere with initially low energies (tens of eV or less) to energies required to create an aurora (100s of eV or greater), allowing that large source of particles to contribute to creating auroral light.

The accelerated electrons carry an electric current along the magnetic field lines (a Birkeland current). Since the electric field points in the same direction as the current, there is a net conversion of electromagnetic energy into particle energy in the auroral acceleration region (an electric load). The energy to power this load is eventually supplied by the magnetized solar wind flowing around the obstacle of Earth's magnetic field, although exactly how that power flows through the magnetosphere is still an active area of research.^[67] While the energy to power the aurora is ultimately derived from the solar wind, the electrons themselves do not travel directly from the solar wind into Earth's auroral zone; magnetic field lines from these regions do not connect to the solar wind, so there is no direct access for solar wind electrons.

Some auroral features are also created by electrons accelerated by dispersive

That aurora is thought to have been produced by one of the most intense coronal mass ejections in history. It is also notable for the fact that it is the first time where the phenomena of auroral activity and electricity were unambiguously linked. This insight was made possible not only due to scientific magnetometer measurements of the era, but also as a result of a significant portion of the 125,000 miles (201,000 km) of telegraph lines then in service being significantly disrupted for many hours throughout the storm. Some telegraph lines, however, seem to have been of the appropriate length and orientation to produce a sufficient geomagnetically induced current from the electromagnetic field to allow for continued communication with the telegraph operator power supplies switched off.^[75] The following conversation occurred between two operators of the American Telegraph Line between Boston and Portland, Maine, on the night of 2 September 1859 and reported in the Boston Traveller:

Boston operator (to Portland operator): "Please cut off your battery [power source] entirely for fifteen minutes."
Portland operator: "Will do so. It is now disconnected."
Boston: "Mine is disconnected, and we are working with the auroral current. How do you receive my writing?"
Portland: "Better than with our batteries on. – Current comes and goes gradually."
Boston: "My current is very strong at times, and we can work better without the batteries, as the aurora seems to neutralize and augment our batteries alternately, making current too strong at times for our relay magnets. Suppose we work without batteries while we are affected by this trouble."
Portland: "Very well. Shall I go ahead with business?"
Boston: "Yes. Go ahead."

The conversation was carried on for around two hours using no

The effect of the Aurora on the electric telegraph is generally to increase or diminish the electric current generated in working the wires. Sometimes it entirely neutralizes them, so that, in effect, no fluid [current] is discoverable in them. The aurora borealis seems to be composed of a mass of electric matter, resembling in every respect, that generated by the electric galvanic battery. The currents from it change coming on the wires, and then disappear: the mass of the aurora rolls from the horizon to the zenith.[76]

In May 2024, a series of solar storms caused the aurora borealis to be observed from as far south as Ferdows, Iran.^[77][78][79]

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. Find sources: "Aurora" Historical views and folklore – news · newspapers · books · scholar · JSTOR (May 2024) (Learn how and when to remove this message)

The earliest datable record of an aurora was recorded in the Bamboo Annals, a historical chronicle of the history of ancient China, in 977 or 957 BC.^[80] An aurora was described by the

In the traditions of

Among the Māori people of New Zealand, aurora australis or Tahunui-a-rangi ("great torches in the sky") were lit by ancestors who sailed south to a "land of ice" (or their descendants);^[88][89] these people were said to be Ui-te-Rangiora's expedition party who had reached the Southern Ocean.^[88] around the 7th century.^[90]

In Scandinavia, the first mention of norðrljós (the northern lights) is found in the Norwegian chronicle

Walter William Bryant wrote in his book Kepler (1920) that Tycho Brahe "seems to have been something of a homoeopathist, for he recommends sulfur to cure infectious diseases 'brought on by the sulfurous vapours of the Aurora Borealis'".^[92]

In 1778, Benjamin Franklin theorized in his paper Aurora Borealis, Suppositions and Conjectures towards forming an Hypothesis for its Explanation that an aurora was caused by a concentration of electrical charge in the polar regions intensified by the snow and moisture in the air:^[93][94][95]

May not then the great quantity of electricity brought into the polar regions by the clouds, which are condens'd there, and fall in snow, which electricity would enter the earth, but cannot penetrate the ice; may it not, I say (as a bottle overcharged) break thro' that low atmosphere and run along in the vacuum over the air towards the equator, diverging as the degrees of longitude enlarge, strongly visible where densest, and becoming less visible as it more diverges; till it finds a passage to the earth in more temperate climates, or is mingled with the upper air?

Observations of the rhythmic movement of compass needles due to the influence of an aurora were confirmed in the Swedish city of Uppsala by Anders Celsius and Olof Hiorter. In 1741, Hiorter was able to link large magnetic fluctuation to the observation of an aurora overhead. This evidence helped to support their theory that 'magnetic storms' are responsible for such compass fluctuations.^[96]

A variety of

In Robert W. Service's satirical poem "The Ballad of the Northern Lights" (1908), a Yukon prospector discovers that the aurora is the glow from a radium mine. He stakes his claim, then goes to town looking for investors.

In the early 1900s, the Norwegian scientist Kristian Birkeland laid the foundation^{[colloquialism]} for the current understanding of geomagnetism and polar auroras.

In

Both Jupiter and Saturn have magnetic fields that are stronger than Earth's (Jupiter's equatorial field strength is 4.3 gauss, compared to 0.3 gauss for Earth), and both have extensive radiation belts. Auroras have been observed on both gas planets, most clearly using the Hubble Space Telescope, and the Cassini and Galileo spacecraft, as well as on Uranus and Neptune.^[100]

The aurorae on Saturn seem, like Earth's, to be powered by the solar wind. However, Jupiter's aurorae are more complex. Jupiter's main auroral oval is associated with the plasma produced by the volcanic moon Io, and the transport of this plasma within the planet's magnetosphere. An uncertain fraction of Jupiter's aurorae are powered by the solar wind. In addition, the moons, especially Io, are also powerful sources of aurora. These arise from electric currents along field lines ("field aligned currents"), generated by a dynamo mechanism due to the relative motion between the rotating planet and the moving moon. Io, which has active volcanism and an ionosphere, is a particularly strong source, and its currents also generate radio emissions, which have been studied since 1955. Using the Hubble Space Telescope, auroras over Io, Europa and Ganymede have all been observed.

Auroras have also been observed on Venus and Mars. Venus has no magnetic field and so Venusian auroras appear as bright and diffuse patches of varying shape and intensity, sometimes distributed over the full disc of the planet.^[101] A Venusian aurora originates when electrons from the solar wind collide with the night-side atmosphere.

An aurora was detected on Mars, on 14 August 2004, by the SPICAM instrument aboard Mars Express. The aurora was located at Terra Cimmeria, in the region of 177° east, 52° south. The total size of the emission region was about 30 km across, and possibly about 8 km high. By analysing a map of crustal magnetic anomalies compiled with data from Mars Global Surveyor, scientists observed that the region of the emissions corresponded to an area where the strongest magnetic field is localized. This correlation indicated that the origin of the light emission was a flux of electrons moving along the crust magnetic lines and exciting the upper atmosphere of Mars.^[100][102]

Between 2014 and 2016, cometary auroras were observed on comet

Exoplanets, such as hot Jupiters, have been suggested to experience ionization in their upper atmospheres and generate an aurora modified by weather in their turbulent tropospheres.^[105] However, there is no current detection of an exoplanet aurora.

The first ever

• Airglow
• Aurora (heraldry)
• Heliophysics
• List of solar storms
• Paschen's law
• Space tornado
• Space weather

References

1. ^ "Southern Lights over the Australian Bight". NASA. Archived from the original on 21 October 2022. Retrieved 12 September 2022.
2. ^ "University of Minnesota Style Manual". .umn.edu. 18 July 2007. Archived from the original on 22 July 2010. Retrieved 5 August 2010.
3. ^ Lui, A., 2019. Imaging global auroras in space. Light: Science & Applications, 8(1).
4. ISSN 8755-1217
   .
5. ^ Guiducci, Mario; Galilei, Galileo (1619). Discorso delle Comete [Discourse on Comets] (in Italian). Firenze (Florence), Italy: Pietro Cecconcelli. p. 39. Archived from the original on 12 May 2024. Retrieved 31 July 2019. On p. 39, Galileo explains that auroras are due to sunlight reflecting from thin, high clouds. From p. 39: "... molti di voi avranno più d'una volta veduto 'l Cielo nell' ore notturne, nelle parti verso Settentrione, illuminato in modo, che di lucidità non-cede alla piu candida Aurora, ne lontana allo spuntar del Sole; effetto, che per mio credere, non-ha origine altrode, che dall' essersi parte dell' aria vaporosa, che circonda la terra, per qualche cagione in modo più del consueto assottigliata, che sublimandosi assai più del suo consueto, abbia sormontato il cono dell' ombra terrestre, si che essendo la sua parte superiore ferita dal Sole abbia potuto rifletterci il suo splendore, e formarci questa boreale aurora." ("... many of you will have seen, more than once, the sky in the night hours, in parts towards the north, illuminated in a way that the clear [sky] does not yield to the brighter aurora, far from the rising of the sun; an effect that, by my thinking, has no other origin than being part of the vaporous air that surrounds the Earth, for some reason thinner than usual, which, being sublimated far more than expected, has risen above the cone of the Earth's shadow, so that its upper part, being struck by the sun['s light], has been able to reflect its splendor and to form this aurora borealis.")
6. ^ ^{a b c d} Harper, Douglas, ed. (2025). "Aurora". Online Etymology Dictionary. Retrieved 5 January 2025.
7. doi:10.1029/EO067i040p00761-02
   .
8. ^
   ISBN 978-94-010-1245-4. Archived
   from the original on 12 May 2024. Retrieved 30 August 2017.
9. ^ ^{a b} See:
   • Loomis, Elias (November 1859). "The great auroral exhibition of August 28 to September, 1859". The American Journal of Science. 2nd series. 28: 385–408. Archived from the original on 13 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (January 1860). "The great auroral exhibition of August 28 to September 4, 1859 – 2nd article". The American Journal of Science. 2nd series. 29: 92–97. Archived from the original on 14 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (February 1860). "The great auroral exhibition of August 28 to September 4, 1859 – 3rd article". The American Journal of Science. 2nd series. 29: 249–266. Archived from the original on 15 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (May 1860). "The great auroral exhibition of August 28 to September 4, 1859 – 4th article". The American Journal of Science. 2nd series. 29: 386–399. Archived from the original on 13 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (July 1860). "The great auroral exhibition of August 28 to September 4, 1859, and the geographical distribution of auroras and thunder storms – 5th article". The American Journal of Science. 2nd series. 30: 79–100. Archived from the original on 14 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (November 1860). "The great auroral exhibition of August 28 to September 4, 1859 – 6th article". The American Journal of Science. 2nd series. 30: 339–361. Archived from the original on 13 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (July 1861). "The great auroral exhibition of August 28 to September 4, 1859 – 7th article". The American Journal of Science. 2nd series. 32: 71–84. Archived from the original on 14 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (September 1861). "On the great auroral exhibition of August 28 to September 4, 1859, and auroras generally – 8th article". The American Journal of Science. 2nd series. 32: 318–335. Archived from the original on 14 May 2021. Retrieved 30 July 2019.
   • Loomis, Elias (July 1862). "On electrical currents circulating near the earth's surface and their connection with the phenomena of the aurora polaris – 9th article". The American Journal of Science. 2nd series. 34: 34–45. Archived from the original on 14 May 2021. Retrieved 30 July 2019.
10. ^ Fritz, Hermann (1881). Das Polarlicht [The Aurora]. Internationale wissenschaftliche Bibliothek (in German). Vol. 49. Leipzig, Germany: F. A. Brockhaus. Archived from the original on 28 August 2021. Retrieved 31 July 2019.
11. ^ Tromholt, Sophus (1881). "Om Nordlysets Perioder / Sur les périodes de l'aurore boréale [On the periods of the aurora borealis]". Meteorologisk Aarbog for 1880. Part 1 (in Danish and French). Copenhagen, Denmark: Danske Meteorologiske Institut. pp. I–LX.
12. doi:10.1016/j.jastp.2006.05.026
    .
13. ^ "Aurora austral en Uruguay: fotógrafos registran un hecho "histórico" y astrónomos explican por qué pasó". El Observador (Uruguay). Retrieved 13 May 2024.
14. doi:10.1029/2005RG000174
    .
15. doi:10.1029/1999JA900311. Archived
    (PDF) from the original on 30 April 2019. Retrieved 7 December 2019.
16. hdl:2027.42/94796. Archived
    (PDF) from the original on 12 May 2024. Retrieved 20 April 2018.
17. doi:10.1029/2003GL017914
    .
18. ^ "Northern Lights". Geiranger Guide. Archived from the original on 1 March 2024. Retrieved 1 March 2024.
19. doi:10.1029/te051i004p00501
    .
20. PMID 17764743
    .
21. doi:10.1016/S1364-6826(96)00113-7
    .
22. ^
    ISBN 978-82-504-2105-9
    .
23. ^
    doi:10.1007/s00585-997-0943-z
    .
24. PMID 16586674
    .
25. ^ "Auroral colors and spectra". Windows to the Universe. Archived from the original on 19 December 2014. Retrieved 13 January 2014.
26. ^ ^{a b} "NASA's MAVEN Orbiter Detects Ultraviolet Aurora on Mars | Space Exploration". Sci-News.com. Archived from the original on 25 July 2015. Retrieved 16 August 2015.
27. ^ "Aurora Borealis". dapep.org. Archived from the original on 19 April 2015. Retrieved 16 August 2015.^{[clarification needed]}
28. ISBN 0-87590-030-5
    .
29. ^ "Eyes on the Aurora, Part 2: What is a Keogram?". Aurorasaurus. 9 September 2020. Archived from the original on 24 February 2022. Retrieved 26 February 2022.
30. S2CID 38394431. Archived
    from the original on 12 May 2024. Retrieved 7 December 2019.
31. doi:10.1029/JA079i028p04227
    .
32. doi:10.1029/jz065i002p00551
    .
33. ^ "Auroras Make Weird Noises, and Now We Know Why". 27 June 2016. Archived from the original on 27 June 2016. Retrieved 28 June 2016.
34. ^ "News: Acoustics researcher finds explanation for auroral sounds". 21 June 2016. Archived from the original on 1 July 2016. Retrieved 28 June 2016.
35. ^ American Geophysical Union (20 August 2018). "New kind of aurora is not an aurora at all". Phys.org. Archived from the original on 30 March 2022. Retrieved 21 August 2018.
36. ^ Andrews, Robin George (3 May 2019). "Steve the odd 'aurora' revealed to be two sky shows in one". National Geographic. Archived from the original on 4 May 2019. Retrieved 4 May 2019.
37. ^
    doi:10.1029/2019GL082460
    .
38. ^ Lipuma, Lauren. "Scientists discover what powers celestial phenomenon STEVE". AGU News. American Geophysical Union. Archived from the original on 4 May 2019. Retrieved 4 May 2019.
39. ^ Saner, Emine (19 March 2018). "'Steve': the mystery purple aurora that rivals the northern lights". The Guardian. Archived from the original on 22 March 2018. Retrieved 22 March 2018.
40. S2CID 213839228. Archived
    from the original on 22 May 2021. Retrieved 22 May 2021.
41. ^ "Citizen scientists discover a new form of the Northern Lights". phys.org. Archived from the original on 22 May 2021. Retrieved 22 May 2021.
42. ^
    doi:10.1029/2020AV000338
    .
43. ^ "Confirmation of an auroral phenomenon". phys.org. Archived from the original on 22 May 2021. Retrieved 22 May 2021.
44. ^ "The discovery of the auroral dunes: How one thing led to another". Aurorasaurus. Archived from the original on 13 May 2021. Retrieved 22 May 2021.
45. ^ "Revontulien 'dyynit', uusia löydöksiä – Aurora 'dunes' revisited". YouTube. 4 May 2021. Archived from the original on 11 December 2021.
46. S2CID 248842161. Archived
    from the original on 12 May 2024. Retrieved 1 December 2022.
47. ISBN 0-912006-60-9
    .
48. ISBN 978-90-277-2471-7
    .
49. doi:10.1029/JZ065i009p02727
    .
50. doi:10.1029/JA093iA07p07441
    .
51. S2CID 4173665
    .
52. ^ "Ultraviolet Waves". Archived from the original on 27 January 2011.
53. ^ "Simultaneous ground and satellite observations of an isolated proton arc at sub-auroral latitudes". Journal of Geophysical Research. 2007. Archived from the original on 5 August 2015. Retrieved 5 August 2015.
54. doi:10.1029/JA074i001p00247
    .
55. doi:10.1029/JA078i028p06802
    .
56. ^ Birkeland, Kristian (1908). The Norwegian Aurora Polaris Expedition 1902–1903. New York: Christiania (Oslo): H. Aschehoug & Co. p. 720. out-of-print, full text online
57. S2CID 123637108
    .
58. doi:10.1029/JA082i013p01933. Archived
    from the original on 4 November 2016. Retrieved 10 November 2017.
59. University of Alaska
    website
60. ^ "NASA – NASA and World Book". Nasa.gov. 7 February 2011. Archived from the original on 5 September 2005. Retrieved 26 July 2011.
61. doi:10.1029/97JA00196
    .
62. doi:10.1029/2009JA014281
    .
63. ^ "NASA – THEMIS Satellites Discover What Triggers Eruptions of the Northern Lights". Nasa.gov. Archived from the original on 29 June 2011. Retrieved 26 July 2011.
64. S2CID 206514133
    .
65. PMID 33758181
    .
66. S2CID 220509575. Archived
    (PDF) from the original on 12 May 2024. Retrieved 1 June 2021.
67. S2CID 214002762. Archived
    (PDF) from the original on 12 May 2024. Retrieved 1 June 2021.
68. doi:10.1349/ddlp.3332
    .
69. ^ Richard Lewis (7 June 2021). "Physicists determine how auroras are created". IOWA university. Archived from the original on 8 June 2021. Retrieved 8 June 2021.
70. PMID 34099653
    .
71. ^ Frost, Natasha (4 October 2017). "1770 Kyoto Diary". Atlas Obscura. Archived from the original on 13 October 2017. Retrieved 13 October 2017.
72. doi:10.1002/2017SW001690
    .
73. doi:10.1098/rstl.1861.0023. Archived
    from the original on 28 August 2021. Retrieved 30 July 2019.
74. ^
    hdl:2060/20050210157
    .
75. ^ Loomis, Elias (January 1860). "The great auroral exhibition of August 28 to September 4, 1859 – 2nd article". The American Journal of Science. 2nd series. 29: 92–97. Archived from the original on 14 May 2021. Retrieved 30 July 2019.
76. OCLC 1115103262
    – via Internet Archive.
77. ^ "وقتی طوفان خورشیدی، آسمان ایران و جهان را رنگ‌آمیزی کرد". زومیت (in Persian). 13 May 2024. Retrieved 20 July 2024.
78. ^ "چطور شد که شفق قطبی در ایران هم دیده شد؟ +عکس". fa (in Persian). Retrieved 20 July 2024.
79. ^ "شفق قطبی در آسمان کویر ایران". BBC News فارسی (in Persian). 12 May 2024. Retrieved 20 July 2024.
80. ^ "Earliest Known Report of Aurora Found in Ancient Chinese Chronicle". SCI News. 12 April 2022. Archived from the original on 5 June 2022. Retrieved 5 June 2022.
81. ^ Macleod, Explorers: Great Tales of Adventure and Endurance, p. 21.
82. ^ Clarke, J. (1910), Physical Science in the time of Nero, pp. 39–41, London: Macmillan, accessed 1 January 2017.
83. ^ Bostock, J. and Riley, H. T. (1855), The Natural History of Pliny, Vol. II, London: Bohn, accessed 1 January 2017.
84. ISBN 978-1-4614-7819-5. Archived
    from the original on 12 May 2024. Retrieved 18 March 2024.
85. ^ Administrator, NASA (7 June 2013). "The History of Auroras". NASA. Archived from the original on 29 March 2023. Retrieved 22 May 2022.
86. ^ "Modern science reveals ancient secret in Japanese literature". phys.org. 30 March 2020. Archived from the original on 1 April 2020. Retrieved 3 April 2020.
87. S2CID 118102443. Archived from the original
    (PDF) on 20 October 2013. Retrieved 19 October 2013.
88. ^
    ISBN 978-0-947518-71-4. Archived
    from the original on 18 April 2024. Retrieved 1 June 2022.
89. ^ Best, Elsdon (1922). The Astronomical Knowledge of the Maori, Genuine and Empirical. Wellington: Dominion Museum. p. 58. Archived from the original on 13 September 2021. Retrieved 13 September 2021 – via Victoria University of Wellington.
90. PMID 39440197
    .
91. ^ "Norrsken history". Irf.se. 12 November 2003. Archived from the original on 21 July 2011. Retrieved 26 July 2011.
92. ^ Walter William Bryant, Kepler. Macmillan Co. (1920) p. 23.
93. ^ The original English text of Benjamin Franklin's article on the cause of auroras is available at: U.S. National Archives: Founders Online Archived 31 July 2019 at the Wayback Machine
94. ^ A translation into French of Franklin's article was read to the French Royal Academy of Sciences and an excerpt of it was published in: Francklin (June 1779). "Extrait des suppositions et des conjectures sur la cause des Aurores Boréales" [Extract of Suppositions and conjectures on the cause of auroras borealis]. Journal de Physique (in French). 13: 409–412. Archived from the original on 27 April 2021. Retrieved 31 July 2019.
95. ISBN 978-0-8122-0561-9
    .
96. ^ J. Oschman (2016), Energy Medicine: The Scientific Basis (Elsevier, Edinburgh), p. 275.
97. ^ Hearne, Samuel (1958). A Journey to the Northern Ocean: A journey from Prince of Wales' Fort in Hudson's Bay to the Northern Ocean in the years 1769, 1770, 1771, 1772. Richard Glover (ed.). Toronto: The MacMillan Company of Canada. pp. 221–222.
98. ^ "Aurora Borealis | Smithsonian American Art Museum". americanart.si.edu. Archived from the original on 27 February 2024. Retrieved 18 April 2024.
99. ^ The National Cyclopaedia of Useful Knowledge, Vol. II (1847), London: Charles Knight, p. 496
100. ^ ^{a b} "ESA Portal – Mars Express discovers auroras on Mars". European Space Agency. 11 August 2004. Archived from the original on 19 October 2012. Retrieved 5 August 2010.
101. ISSN 1944-8007. Archived
     from the original on 22 January 2021. Retrieved 17 January 2021.
102. ^ "Mars Express Finds Auroras on Mars". Universe Today. 18 February 2006. Archived from the original on 10 February 2007. Retrieved 5 August 2010.
103. ^ "Comet Chury's ultraviolet aurora". Portal. 21 September 2020. Archived from the original on 16 January 2021. Retrieved 17 January 2021.
104. ^
     S2CID 221884342. Archived
     from the original on 9 April 2022. Retrieved 17 January 2021.
105. PMID 31378171
     .
106. ^ O'Neill, Ian (29 July 2015). "Monstrous Aurora Detected Beyond our Solar System". Discovery. Archived from the original on 31 July 2015. Retrieved 29 July 2015.
107. ^ Q. Choi, Charles (29 July 2015). "First Alien Auroras Found, Are 1 Million Times Brighter Than Any on Earth". space.com. Archived from the original on 30 July 2015. Retrieved 29 July 2015.

Further reading

• Procter, Henry Richardson (1878). "Aurora Polaris" . Encyclopædia Britannica. Vol. III (9th ed.). pp. 90–99.
• Chree, Charles (1911). "Aurora Polaris" . Encyclopædia Britannica. Vol. 2 (11th ed.). pp. 927–934. These two both include detailed descriptions of historical observations and descriptions.
• Stern, David P. (1996). "A Brief History of Magnetospheric Physics During the Space Age". Reviews of Geophysics. 34 (1): 1–31.
  doi:10.1029/95rg03508
  .
• Stern, David P.; Peredo, Mauricio. "The Exploration of the Earth's Magnetosphere". phy6.org.
• Eather, Robert H. (1980). Majestic Lights: The Aurora in Science, History, and The Arts. Washington, DC: American Geophysical Union.
  ISBN 978-0-87590-215-9
  .
• Akasofu, Syun-Ichi (April 2002). "Secrets of the Aurora Borealis". Alaska Geographic Series. 29 (1).
• Daglis, Ioannis; Akasofu, Syun-Ichi (November 2004). "Aurora – The magnificent northern lights" (PDF). Recorder. 29 (9): 45–48. Archived from the original (PDF) on 14 June 2020. Alt URL
• Savage, Candace Sherk (1994). Aurora: The Mysterious Northern Lights. San Francisco:
  ISBN 978-0-87156-419-1
  .
• Hultqvist, Bengt (2007). "The Aurora". In Kamide, Y.; Chian, A (eds.). Handbook of the Solar-Terrestrial Environment. Berlin Heidelberg: Springer-Verlag. pp. 331–354.
  ISBN 978-3-540-46314-6
  .
• Sandholt, Even; Carlson, Herbert C.; Egeland, Alv (2002). "Optical Aurora". Dayside and Polar Cap Aurora. Netherlands: Springer Netherlands. pp. 33–51.
  ISBN 978-0-306-47969-4
  .
• Phillips, Tony (21 October 2001). "'tis the Season for Auroras". NASA. Archived from the original on 11 April 2006. Retrieved 15 May 2006.
• Davis, Neil (1992). The Aurora Watcher's Handbook. University of Alaska Press.
  ISBN 0-912006-60-9
  .

External links

This article's use of external links may not follow Wikipedia's policies or guidelines. Please improve this article by removing excessive or inappropriate external links, and converting useful links where appropriate into footnote references. (November 2024) (Learn how and when to remove this message)

Wikimedia Commons has media related to Aurora.

Wikiquote has quotations related to Aurora.

Wikivoyage has a travel guide for Northern Lights.

Wikisource has original text related to this article:

Aurora

• Aurora forecast – Will there be northern lights?
• Current global map showing the probability of visible aurora
• Aurora – Forecasting (archived 24 November 2016)
• Official MET aurora forecasting in Iceland
• Aurora Borealis – Predicting
• Solar Terrestrial Data – Online Converter – Northern Lights Latitude
• Aurora Service Europe – Aurora forecasts for Europe (archived 11 March 2019)
• Live Northern Lights webstream
• World's Best Aurora – The Northwest Territories is the world's Northern Lights mecca.

Multimedia

• Amazing time-lapse video of Aurora Borealis – Shot in Iceland over the winter of 2013/2014
• Popular video of Aurora Borealis – Taken in Norway in 2011
• Aurora Photo Gallery – Views taken 2009–2011 (archived 4 October 2011)
• Aurora Photo Gallery – "Full-Sky Aurora" over Eastern Norway. December 2011
• Videos and Photos – Auroras at Night (archived 2 September 2010)
• Video (04:49) – Aurora Borealis – How The Northern Lights Are Created (video on YouTube)
• Video (47:40) – Northern Lights – Documentary
• Video (5:00) – Northern lights video in real time
• Video (01:42) – Northern Light – Story of Geomagnetic Storm (Terschelling Island – 6/7 April 2000) (archived 17 August 2011)
• Video (01:56) (time-lapse) − Auroras – Ground-Level View from
  Finnish Lapland 2011 (video on YouTube
  )
• Video (02:43) (time-lapse) − Auroras – Ground-Level View from Tromsø, Norway, 24 November 2010 (video on YouTube)
• Video (00:27) (time-lapse) – Earth and Auroras – Viewed from the International Space Station (video on YouTube)