Auroras Occur In Which Layer Of Atmosphere Reason

The aurora borealis and aurora australis occur in the thermosphere. Therefore, the best times to see auroras occur in the winter, when nights are longest. Auroras also become more frequent when the sun is most active during its 11-year cycle.Find an answer to your question ✅ "Auroras occur in the what atmosphere" in Physics if you're in doubt about the correctness of the answers or there's no answer, then try to use the smart search and find answers to the similar questions.Auroras occur in both hemispheres at the same time, as shown in this image captured by NASA's Polar Visible Imaging System. This is not because the auroras are seasonal - in fact, satellite pictures reveal that auroras occur simultaneously in the two polar regions of the magnetosphere.The aurora is accompanied by various VLF radio emissions that cannot be observed by radio devices on the ground. The discharge-current-carrying electrons are accelerated in the auroral potential structure, which is located at an altitude of ∼10,000 km above the aurora (see Section VI).The auroras can be found at high latitudes, near the north and south magnetic poles. They occur when solar winds interact with different elements in the planet's atmosphere. These winds come from the sun at speeds of around 1 million miles per hour and reach our planet about 40 hours after leaving the sun.

Auroras occur in the what atmosphere

However, auroras also occur in the F-layer of the ionosphere, which is located above the E-layer that is located between 150 km and 500 km (90 mi The aurora is distributed across something called the 'auroral oval', which sits around the north (or south) pole and extends for some distance towards the...Auroras, often called Northern Lights (Aurora Borealis) and Southern Lights (Aurora Australis) are spectacular light displays most commonly viewed in the polar regions. Auroras occur because of interactions between Earth's magnetic field and solar winds.As Iceland sits in a sweet spot within the Aurora belt, travellers frequently get the pleasure of witnessing one of nature's greatest phenomenons This is why scientists have the assumption that for auroras to occur on other planets in any form, they would at least need to have a magnetic field.Why is it that Auroras only occur in the North and South poles. Auroras themselves are just emissions from our atmosphere in response to being bombarded by high energy particles. To put this all together, here's what happens: The Sun spews out huge amounts of energy and tons of charged...

Auroras | Causes of Color

The aurora borealis lights up the sky over a house in Norway. Photograph by Sergio Pitamitz, Nat Geo Image Collection. Please be respectful of copyright. Charged particles are constantly streaming from the sun in the solar wind, and auroras occur when these particles interact with Earth's magnetic field."Auroras in the north and south can be nearly mirror images of each other. Such mirroring had been suspected for centuries but dramatically confirmed only last month by detailed images from NASA's orbiting Polar The aurora imaged on the right occurred over Finland in early October 2002.Aurora comes in several different shapes. Often the auroral forms are made of many tall rays that look much like a curtain made of folds of cloth. When space weather activity increases and more frequent and larger storms and substorms occur, the aurora extends equatorward.The electrons that create auroras start in the outer layers of the field, where it is compressed by the solar wind. This results in an oval ring around each magnetic pole where auroras occur. The north pole aurora is called the aurora borealis and the aurora at the south pole is called the aurora australis.particularly in the polar regions. They typically occur in the ionosphere. They are also referred to as polar auroras.

Jump to navigation Jump to search Several terms redirect here. For other uses, see Aurora (disambiguation), Aurora Australis (disambiguation), Aurora Borealis (disambiguation), Northern Lights (disambiguation) and Southern Lights (disambiguation).

Images of auroras from around the world, together with those with rarer crimson and blue lighting fixturesAurora australis from the ISS, 2017. Video of this encounter: [2]

An aurora (plural: auroras or aurorae),[a] infrequently referred to as polar lights (aurora polaris), northern lights (aurora borealis), or southern lighting fixtures (aurora australis), is a herbal mild show in the Earth's sky, predominantly viewed in high-latitude areas (round the Arctic and Antarctic).

Auroras are the result of disturbances in the magnetosphere caused by solar wind. These disturbances are from time to time robust enough to vary the trajectories of charged debris in both photo voltaic wind and magnetospheric plasma. These particles, mainly electrons and protons, precipitate into the higher setting (thermosphere/exosphere).

The resulting ionization and excitation of atmospheric constituents emit gentle of varying colour and complexity. The form of the aurora, going on inside bands around each polar areas, could also be dependent on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the setting. Proton auroras are usually seen at decrease latitudes.[2]

Most of the planets in our solar device, some natural satellites, brown dwarfs, or even comets additionally host auroras.

Etymology

The word "aurora" is derived from the title of the Roman goddess of the morning time, Aurora, who travelled from east to west saying the coming of the sun.[3] Ancient Greek poets used the identify metaphorically to check with morning time, often bringing up its play of colors throughout the differently darkish sky (e.g., "rosy-fingered dawn"). [4]

Occurrence

Most auroras occur in a band known as the "auroral zone",[5] which is generally 3° to six° vast in latitude and between 10° and 20° from the geomagnetic poles at all native times (or longitudes), maximum clearly seen at night in opposition to a dismal sky. A area that recently displays an aurora is named the "auroral oval", a band displaced by the photo voltaic wind towards the night side of the Earth.[6] Early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis (1860),[7] and later Hermann Fritz (1881)[8] and Sophus Tromholt (1881)[9] in more detail, established that the aurora gave the impression basically in the auroral zone. Day-to-day positions of the auroral ovals are posted on the Internet.[10]

In northern latitudes, the impact is known as the aurora borealis or the northern lighting. The former term used to be coined by Galileo in 1619, from the Roman goddess of the morning time and the Greek identify for the north wind.[11][12] The southern counterpart, the aurora australis or the southern lighting fixtures, has features almost just like the aurora borealis and changes simultaneously with adjustments in the northern auroral zone.[13] The aurora australis is visible from high southern latitudes in Antarctica, Chile, Argentina, New Zealand, and Australia.

A geomagnetic hurricane reasons the auroral ovals (north and south) to increase, bringing the aurora to lower latitudes. The on the spot distribution of auroras ("auroral oval")[5] is reasonably other, being focused about 3–5° nightward of the magnetic pole, in order that auroral arcs achieve furthest towards the equator when the magnetic pole in query is in between the observer and the Sun. The aurora may also be viewed perfect at this time, which is called magnetic midnight.

Auroras viewed inside of the auroral oval is also without delay overhead, but from farther away, they illuminate the poleward horizon as a greenish glow, or every now and then a faint red, as if the Sun were rising from an ordinary direction. Auroras also occur poleward of the auroral zone as either diffuse patches or arcs,[14] which can also be subvisual.

Videos of the aurora australis taken via the crew of Expedition 28 on board the International Space Station">Play mediaThis 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">Play mediaThis sequence of pictures 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">Play mediaThis series of pictures used to be taken 11 September 2011 from 13:45:06 to fourteen:01:51 GMT, from a descending go near japanese Australia, rounding about to an ascending go to the east of New Zealand NOAA maps of North America and EurasiaNorth AmericaEurasiaThese maps show the native middle of the night equatorward boundary of the aurora at different levels of geomagnetic job.A Kp=3 corresponds to low levels of geomagnetic activity, whilst Kp=Nine represents high levels.

Auroras are every now and then seen in latitudes underneath the auroral zone, when a geomagnetic storm quickly enlarges the auroral oval. Large geomagnetic storms are most commonplace right through the peak of the 11-year sunspot cycle or throughout the three years after the height.[15][16] An electron spirals (gyrates) a few box line at an attitude this is made up our minds via its speed vectors, parallel and perpendicular, respectively, to the native geomagnetic box vector B. This perspective is known as the "pitch angle" of the particle. The distance, or radius, of the electron from the box line at any time is known as its Larmor radius. The pitch angle will increase as the electron travels to a region of larger box strength closer to the environment. Thus, it's imaginable for some particles to return, or mirror, if the angle turns into 90° before entering the environment to collide with the denser molecules there. Other particles that do not replicate input the surroundings and contribute to the auroral show over a range of altitudes. Other types of auroras have been noticed from area, e.g."poleward arcs" stretching sunward throughout the polar cap, the similar "theta aurora",[17] and "dayside arcs" close to noon. These are somewhat infrequent and poorly understood. Other fascinating effects occur equivalent to flickering aurora, "black aurora" and subvisual purple arcs. In addition to these types of, a vulnerable glow (usally deep red) seen around the two polar cusps, the field lines separating the ones that shut through the Earth from those which might be swept into the tail and close remotely.

Images ">Play media Video of the aurora borealis from the International Space Station

The altitudes the place auroral emissions occur were published via Carl Størmer and his colleagues, who used cameras to triangulate more than 12,000 auroras.[18] They came upon that most of the light is produced between Ninety and 150 km above the floor, whilst extending from time to time to more than 1000 km. Images of auroras are significantly extra common lately than in the previous due to the building up in the use of digital cameras that have high enough sensitivities.[19] Film and digital publicity to auroral displays is fraught with difficulties. Due to the different shade spectra provide, and the temporal adjustments going on all the way through the publicity, the effects are rather unpredictable. Different layers of the film emulsion reply in a different way to lower gentle levels, and number of a movie may also be very important. Longer exposures superimpose unexpectedly changing options, and usally blanket the dynamic characteristic of a show. Higher sensitivity creates issues with graininess.

David Malin pioneered more than one exposure using more than one filters for astronomical photography, recombining the pictures in the laboratory to recreate the visible display more appropriately.[20] For medical analysis, proxies are often used, equivalent to ultraviolet, and color-correction to simulate the look to people. Predictive techniques are also used, to signify the extent of the show, a highly useful tool for aurora hunters.[21] Terrestrial features usally to find their approach into aurora photographs, making them extra accessible and much more likely to be published through main web sites.[22] Excellent pictures are conceivable with usual film (using ISO ratings between 100 and 400) and a single-lens reflex digicam with full aperture, a fast lens (f1.4 50 mm, for instance), and exposures between 10 and 30 seconds, depending on the aurora's brightness.[23]

Early paintings on the imaging of the auroras was performed in 1949 via the University of Saskatchewan the use of the SCR-270 radar.

Aurora throughout a geomagnetic storm that was most likely brought about by means of a coronal mass ejection from the Sun on 24 May 2010, taken from the ISS

Diffuse aurora observed by way of DE-1 satellite tv for pc from high Earth orbit

Estonia, 18 March 2015

Forms of auroras

According to Clark (2007), there are 4 primary bureaucracy that may be viewed from the floor, from least to most seen:[24]

Different forms A light glow, near the horizon. These can also be with reference to the limit of visibility,[25] however will also be prominent from moonlit clouds because stars can be viewed undiminished through the glow. Patches or surfaces that appear to be clouds. Arcs curve throughout the sky. Rays are mild and dark stripes throughout arcs, achieving upwards by way of quite a lot of quantities. Coronas duvet a lot of the sky and diverge from one level on it.

Brekke (1994) also described some auroras as curtains.[26] The similarity to curtains is usally enhanced by folds inside the arcs. Arcs can fragment or get a divorce into separate, every now and then all of a sudden changing, usally rayed features that can fill the entire sky. These are sometimes called discrete auroras, which might be at times vibrant enough to learn a newspaper by at night.[27]

These paperwork are in step with auroras' being shaped by means of Earth's magnetic box. The appearances of arcs, rays, curtains, and coronas are made up our minds by means of the shapes of the luminous parts of the environment and a viewer's place.[28]

Colors and wavelengths of auroral gentle Red: At its very best altitudes, excited atomic oxygen emits at 630 nm (red); low concentration of atoms and decrease sensitivity of eyes at this wavelength make this color seen handiest beneath more intense photo voltaic task. The low number of oxygen atoms and their steadily diminishing concentration is chargeable for the faint appearance of the best portions of the "curtains". Scarlet, crimson, and carmine are the maximum often-seen hues of pink for the auroras. Green: At decrease altitudes, the more common collisions suppress the 630 nm (pink) mode: fairly the 557.7 nm emission (inexperienced) dominates. A slightly excessive concentration of atomic oxygen and higher eye sensitivity in inexperienced make inexperienced auroras the maximum not unusual. The excited molecular nitrogen (atomic nitrogen being uncommon due to the excessive steadiness of the N2 molecule) performs a role here, as it could possibly transfer energy by way of collision to an oxygen atom, which then radiates it away at the inexperienced wavelength. (Red and inexperienced can also combine together to produce crimson or yellow hues.) The fast lower of concentration of atomic oxygen below about 100 km is responsible for the abrupt-looking finish 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 answerable for the graduality (0.7 s and 107 s respectively) of flaring and fading. Blue: At yet lower altitudes, atomic oxygen is rare, and molecular nitrogen and ionized molecular nitrogen take over in producing seen mild emission, radiating at a large number of wavelengths in each pink and blue portions of the spectrum, with 428 nm (blue) being dominant. Blue and pink emissions, typically at the lower edges of the "curtains", show up at the very best ranges of photo voltaic process.[29] The molecular nitrogen transitions are much quicker than the atomic oxygen ones. Ultraviolet: Ultraviolet radiation from auroras (inside of the optical window but not seen to nearly all humans) has been noticed with the requisite apparatus. Ultraviolet auroras have also been considered on Mars,[30] Jupiter and Saturn. Infrared: Infrared radiation, in wavelengths which might be inside the optical window, may be part of many auroras.[30][31] Yellow and crimson are a mixture of red and green or blue. Other sunglasses of purple, as well as orange, is also seen on uncommon occasions; yellow-green is reasonably commonplace. As purple, inexperienced, and blue are the number one colours of additive synthesis of colours, in theory, practically any coloration could be imaginable, but the ones discussed in this text contain a virtually exhaustive record.Changes with time

Auroras change with time. Over the evening, they begin with glows and growth against coronas, even supposing they won't reach them. They generally tend to fade in the reverse order.[26]

At shorter time scales, auroras can exchange their appearances and depth, once in a while so slowly as to be tricky to notice, and at different instances unexpectedly all the way down to the sub-second scale.[27] The phenomenon of pulsating auroras is an instance of intensity permutations over short timescales, generally with classes of two–20 seconds. This type of aurora is generally accompanied by means of lowering height emission heights of about 8 km for blue and inexperienced emissions and above moderate photo voltaic wind speeds (~ 500 km/s).[32]

Other auroral radiation

In addition, the aurora and associated currents produce a strong radio emission around 150 kHz known as auroral kilometric radiation (AKR), came upon in 1972.[33] Ionospheric absorption makes AKR simplest observable from space. X-ray emissions, originating from the debris related to auroras, have additionally been detected.[34]

Aurora noise

Aurora noise, very similar to a hissing, or crackling noise, begins about 70 m (230 ft) above the Earth's floor and is led to via charged particles in an inversion layer of the setting formed during a cold evening. The charged particles discharge when particles from the Sun hit the inversion layer, creating the noise.[35][36]

Atypical auroras STEVE

In 2016, more than fifty citizen science observations described what was once to them an unknown form of aurora which they named "STEVE," for "Strong Thermal Emission Velocity Enhancement." STEVE isn't an aurora however is caused by way of a 25 km (16 mi) large ribbon of scorching plasma at an altitude of 450 km (280 mi), with a temperature of 6,000 Okay (5,730 °C; 10,340 °F) and flowing at a pace of 6 km/s (3.7 mi/s) (compared to 10 m/s (33 feet/s) out of doors the ribbon).[37]

Picket-fence aurora

The processes that cause STEVE also are related to a picket-fence aurora, even though the latter will also be seen without STEVE.[38][39] It is an aurora because it is brought about by way of precipitation of electrons in the environment but it seems that outside the auroral oval,[40] nearer to the equator than conventional auroras.[41] When the picket-fence aurora appears with STEVE, it is underneath.[39]

Causes

A complete working out of the bodily processes which result in several types of auroras continues to be incomplete, however the elementary reason comes to the interplay of the solar wind with the Earth's magnetosphere. The various depth of the solar wind produces results of different magnitudes however comprises one or more of the following physical situations.

A quiescent solar wind flowing previous the Earth's magnetosphere often interacts with it and can both inject solar wind debris directly onto the geomagnetic field strains which can be 'open', versus being 'closed' in the reverse hemisphere, and provide diffusion through the bow shock. It too can purpose debris already trapped in the radiation belts to precipitate into the surroundings. Once particles are misplaced to the environment from the radiation belts, underneath quiet stipulations, new ones change them most effective slowly, and the loss-cone turns into depleted. In the magnetotail, on the other hand, particle trajectories seem constantly to reshuffle, most definitely when the particles pass the very weak magnetic box near the equator. As a end result, the drift of electrons in that region is nearly the similar in all instructions ("isotropic") and assures a gentle provide of leaking electrons. The leakage of electrons does not leave the tail positively charged, because each leaked electron misplaced to the setting is changed through a low energy electron drawn upward from the ionosphere. Such replacement of "hot" electrons through "cold" ones is in complete accord with the 2nd legislation of thermodynamics. The entire process, which also generates an electrical ring current round the Earth, is unsure. Geomagnetic disturbance from an enhanced photo voltaic wind reasons distortions of the magnetotail ("magnetic substorms"). These 'substorms' generally tend to occur after extended spells(hours) right through which the interplanetary magnetic box has had an considerable southward component. This results in a better charge of interconnection between its box strains and the ones of Earth. As a end result, the solar wind moves magnetic flux (tubes of magnetic box lines, 'locked' together with their resident plasma) from the day aspect of Earth to the magnetotail, widening the obstacle it items to the photo voltaic wind go with the 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 photo voltaic wind; others are squeezed toward Earth the place their movement feeds robust outbursts of auroras, basically around nighttime ("unloading process"). A geomagnetic typhoon as a result of better interplay provides many extra debris to the plasma trapped round Earth, additionally generating enhancement of the "ring current". Occasionally the resulting modification of the Earth's magnetic box can be so robust that it produces auroras seen at middle latitudes, on field traces a lot closer to the equator than the ones of the auroral zone. Moon and Aurora Acceleration of auroral charged particles invariably accompanies a magnetospheric disturbance that causes an aurora. This mechanism, which is believed to predominantly get up from strong electrical fields along the magnetic field or wave-particle interactions, raises the pace of a particle in the direction of the guiding magnetic box. The pitch angle is thereby diminished and increases the probability of it being brought about into the environment. Both electromagnetic and electrostatic waves, produced at the time of greater geomagnetic disturbances, make a vital contribution to the energizing processes that maintain an aurora. Particle acceleration provides a complex intermediate process for moving power from the solar wind not directly into the atmosphere. Aurora australis (11 September 2005) as captured by NASA's IMAGE satellite, digitally overlaid onto The Blue Marble composite symbol. An animation created using the same satellite knowledge may be available

The main points of these phenomena aren't absolutely understood. However, it is transparent that the top supply of auroral debris is the photo voltaic wind feeding the magnetosphere, the reservoir containing the radiation zones and temporarily magnetically-trapped particles confined by the geomagnetic box, coupled with particle acceleration processes.[42]

Auroral particles

The instant explanation for the ionization and excitation of atmospheric constituents resulting in auroral emissions was discovered in 1960, when a pioneering rocket flight from Fort Churchill in Canada printed a flux of electrons coming into the surroundings from above.[43] Since then an intensive choice of measurements has been obtained painstakingly and with ceaselessly improving solution since the Nineteen Sixties by many research groups the use of rockets and satellites to traverse the auroral zone. The major findings were that auroral arcs and other bright bureaucracy are because of electrons that have been accelerated during the ultimate few 10,000 km or so in their plunge into the atmosphere.[44] These electrons usally, however not all the time, showcase a height in their energy distribution, and are preferentially aligned along the local path of the magnetic box. Electrons mainly chargeable for diffuse and pulsating auroras have, in contrast, a smoothly falling energy distribution, and an angular (pitch-angle) distribution favouring instructions perpendicular to the local magnetic field. Pulsations had been discovered to originate at or with reference to the equatorial crossing point of auroral zone magnetic box lines.[45] Protons also are related to auroras, each discrete and diffuse.

Auroras and the setting

Auroras result from emissions of photons in the Earth's upper surroundings, above 80 km (50 mi), from ionized nitrogen atoms regaining an electron, and oxygen atoms and nitrogen based totally molecules returning from an excited state to ground state.[46] They are ionized or keen on the collision of debris induced into the surroundings. Both incoming electrons and protons could also be involved. Excitation energy is misplaced inside of the environment through the emission of a photon, or through collision with another atom or molecule:

oxygen emissions green or orange-red, relying on the quantity of power absorbed. nitrogen emissions blue, crimson or pink; blue and crimson if the molecule regains an electron after it's been ionized, purple if returning to flooring state from an excited state.

Oxygen is extraordinary in terms of its go back to flooring state: it will probably take 0.7 seconds to emit the 557.7 nm green light and as much as two minutes for the red 630.0 nm emission. Collisions with different atoms or molecules absorb the excitation power and prevent emission, this procedure is known as collisional quenching. Because the absolute best portions of the setting contain the next proportion of oxygen and lower particle densities, such collisions are uncommon enough to permit time for oxygen to emit red light. Collisions turn into extra widespread progressing down into the surroundings because of increasing density, so that red emissions don't have time to occur, and in the end, even inexperienced light emissions are prevented. This is why there is a color differential with altitude; at high altitudes oxygen pink dominates, then oxygen green and nitrogen blue/crimson/crimson, then in the end nitrogen blue/crimson/red when collisions save you oxygen from emitting anything else. Green is the maximum common colour. Then comes red, a mix of light inexperienced and pink, adopted by pure crimson, then yellow (a mix of purple and inexperienced), and after all, natural blue.

Auroras and the ionosphere

Bright auroras are normally associated with Birkeland currents (Schield et al., 1969;[47] Zmuda and Armstrong, 1973[48]), which flow down into the ionosphere on one aspect of the pole and out on the other. In between, a few of the present connects at once through the ionospheric E layer (125 km); the relaxation ("region 2") detours, leaving again thru field strains closer to the equator and shutting thru the "partial ring current" carried by means of 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 provide. Electric box probes in orbit above the polar cap suggest voltages of the order of 40,000 volts, rising up to greater than 200,000 volts right through intense magnetic storms. In any other interpretation, the currents are the direct results of electron acceleration into the atmosphere by way of wave/particle interactions.

Ionospheric resistance has a complex nature, and leads to a secondary Hall present go with the flow. By a ordinary twist of physics, the magnetic disturbance on the floor because of the main present virtually cancels out, so maximum of the observed impact of auroras is because of a secondary present, the auroral electrojet. An auroral electrojet index (measured in nanotesla) is continuously derived from ground knowledge and serves as a basic measure of auroral activity. Kristian Birkeland[49] deduced that the currents flowed in the east–west directions along the auroral arc, and such currents, flowing from the dayside toward (roughly) nighttime have been later named "auroral electrojets" (see also Birkeland currents).

Interaction of the photo voltaic wind with Earth

The Earth is repeatedly immersed in the solar wind, a rarefied flow of magnetized hot plasma (a gasoline of free electrons and positive ions) emitted by the Sun in all instructions, a results of the two-million-degree temperature of the Sun's outermost layer, the corona. The quiescent photo voltaic wind reaches Earth with a velocity usually around 400 km/s, a density of around Five ions/cm3 and a magnetic box intensity of around 2–5 nT (for comparison, Earth's floor box is typically 30,000–50,000 nT). During magnetic storms, in explicit, flows may also be several occasions faster; the interplanetary magnetic field (IMF) can be much stronger. Joan Feynman deduced in the Seventies that the long-term averages of solar wind pace correlated with geomagnetic task.[50] Her paintings resulted from information collected by the Explorer 33 spacecraft. The solar wind and magnetosphere consist of plasma (ionized gasoline), which conducts electricity. It is well known (since Michael Faraday's work around 1830) that after an electrical conductor is positioned within a magnetic field whilst relative movement occurs in a course that the conductor cuts throughout (or is minimize by means of), relatively than along, the traces of the magnetic field, an electrical current is triggered inside of the conductor. The energy of the present will depend on a) the charge of relative movement, b) the energy of the magnetic field, c) the selection of conductors ganged together and d) the distance between the conductor and the magnetic box, while the path of glide will depend on the route of relative motion. Dynamos make use of this elementary process ("the dynamo effect"), any and all conductors, solid or otherwise are so affected, together with plasmas and other fluids. The IMF originates on the Sun, related to the sunspots, and its box lines (lines of drive) are dragged out by way of the solar wind. That alone would tend to line them up in the Sun-Earth path, however the rotation of the Sun angles them at Earth via about Forty five levels forming a spiral in the ecliptic aircraft), referred to as the Parker spiral. The field lines passing Earth are therefore normally linked to these near the western edge ("limb") of the seen Sun at any time.[51] The solar wind and the magnetosphere, being two electrically carrying out fluids in relative movement, must be ready in principle to generate electrical currents through dynamo motion and impart energy from the flow of the solar wind. However, this process is hampered by means of the proven fact that plasmas behavior readily along magnetic field traces, however less readily perpendicular to them. Energy is more effectively transferred by means of the brief magnetic connection between the field traces of the photo voltaic wind and those of the magnetosphere. Unsurprisingly this process is known as magnetic reconnection. As already discussed, it occurs most readily when the interplanetary field is directed southward, in a an identical route to the geomagnetic box in the interior areas of each the north magnetic pole and south magnetic pole.

Schematic of Earth's magnetosphere

Auroras are more common and brighter throughout the intense section of the photo voltaic cycle when coronal mass ejections build up the intensity of the photo voltaic wind.[52]

Magnetosphere

Earth's magnetosphere is formed by means of the have an effect on of the solar wind on the Earth's magnetic box. This bureaucracy an obstacle to the float, diverting it, at a median distance of about 70,000 km (11 Earth radii or Re),[53] generating a bow shock 12,000 km to 15,000 km (1.9 to two.4 Re) additional upstream. The width of the magnetosphere abreast of Earth, is typically 190,000 km (30 Re), and on the evening side an extended "magnetotail" of stretched field strains extends to great distances (> 200 Re). The high latitude magnetosphere is filled with plasma as the solar wind passes the Earth. The go with the flow of plasma into the magnetosphere increases with additional turbulence, density, and pace in the photo voltaic wind. This waft is preferred by means of a southward component of the IMF, which is able to then immediately connect with the excessive latitude geomagnetic field lines.[54] The drift development of magnetospheric plasma is basically from the magnetotail towards the Earth, round the Earth and again into the photo voltaic wind thru the magnetopause on the day-side. In addition to shifting perpendicular to the Earth's magnetic field, some magnetospheric plasma travels down along the Earth's magnetic field traces, features further energy and loses it to the setting in the auroral zones. The cusps of the magnetosphere, isolating geomagnetic box lines that close via the Earth from those who shut remotely permit a small amount of solar wind to immediately achieve the most sensible of the surroundings, producing an auroral glow. On 26 February 2008, THEMIS probes were in a position to resolve, for the first time, the triggering tournament for the onset of magnetospheric substorms.[55] Two of the five probes, positioned roughly one 3rd the distance to the moon, measured occasions suggesting a magnetic reconnection event 96 seconds previous to auroral intensification.[56]

Geomagnetic storms that ignite auroras may occur extra often all over the months round the equinoxes. It is not neatly understood, however geomagnetic storms would possibly range with Earth's seasons. Two components to consider are the tilt of both the photo voltaic and Earth's axis to the ecliptic airplane. As the Earth orbits all over a year, it reports an interplanetary magnetic field (IMF) from other latitudes of the Sun, which is tilted at Eight levels. Similarly, the 23-degree tilt of the Earth's axis about which the geomagnetic pole rotates with a diurnal variation changes the day by day average attitude that the geomagnetic field items to the incident IMF during a year. These elements combined can lead to minor cyclical changes in the detailed method that the IMF links to the magnetosphere. In turn, this impacts the moderate chance of opening a door through which energy from the photo voltaic wind can succeed in the Earth's internal magnetosphere and thereby fortify auroras. Recent proof in 2021 has shown that specific separate substorms may in fact be correlated networked communities.[57]

Auroral particle acceleration

The electrons answerable for the brightest types of the aurora are smartly accounted for by their acceleration in the dynamic electric fields of plasma turbulence encountered all the way through precipitation from the magnetosphere into the auroral surroundings. In distinction, static electrical fields are unable to switch power to the electrons because of their conservative nature.[58] The electrons and ions that purpose the diffuse aurora seem to not be sped up during precipitation. The building up in energy of magnetic field strains in opposition to the Earth creates a 'magnetic mirror' that turns again many of the downward flowing electrons. The brilliant types of auroras are produced when downward acceleration no longer handiest will increase the power of precipitating electrons but additionally reduces their pitch angles (attitude between electron speed and the native magnetic field vector). This greatly increases the charge of deposition of power into the atmosphere, and thereby the charges of ionization, excitation and consequent emission of auroral mild. Acceleration additionally will increase the electron present flowing between the surroundings and magnetosphere.

One early idea proposed for the acceleration of auroral electrons is based on an assumed static, or quasi-static, electrical field making a uni-directional attainable drop.[59] No mention is equipped of either the necessary space-charge or equipotential distribution, and those stay to be specified for the notion of acceleration via double layers to be credible. Fundamentally, Poisson's equation signifies that there will also be no configuration of price resulting in a web possible drop. Inexplicably although, some authors[60][61] still invoke quasi-static parallel electric fields as internet accelerators of auroral electrons, citing interpretations of transient observations of fields and particles as supporting this concept as company truth. In every other instance,[62] there's little justification given for saying 'FAST observations show detailed quantitative settlement between the measured electrical potentials and the ion beam energies...., leaving no doubt that parallel doable drops are a dominant supply of auroral particle acceleration'.

Another principle is in accordance with acceleration by means of Landau[63] resonance in the turbulent electric fields of the acceleration area. This procedure is basically the identical as that hired in plasma fusion laboratories right through the global,[64] and looks smartly in a position to account in theory for many – if not all – detailed homes of the electrons accountable for the brightest types of auroras, above, underneath and inside of the acceleration area.[65]

ISS Expedition 6 workforce, Lake Manicouagan is visible to the backside left

Other mechanisms have additionally been proposed, in explicit, Alfvén waves, wave modes involving the magnetic box first famous by means of Hannes Alfvén (1942),[66] that have been seen in the laboratory and in area. The query is whether those waves may simply be a special way of shopping at the above procedure, alternatively, because this means does now not indicate a distinct power supply, and lots of plasma bulk phenomena can also be described in terms of Alfvén waves. Other processes also are concerned in the aurora, and far is still discovered. Auroral electrons created through large geomagnetic storms usally seem to have energies below 1 keV and are stopped higher up, near 200 km. Such low energies excite principally the red line of oxygen so that usally such auroras are purple. On the different hand, certain ions additionally succeed in the ionosphere at such time, with energies of 20–30 keV, suggesting they may well be an "overflow" along magnetic field strains of the copious "ring current" ions accelerated at such times, by means of processes other from the ones described above. Some O+ ions ("conics") also appear sped up in different ways through plasma processes related to the aurora. These ions are accelerated through plasma waves in directions mainly perpendicular to the box traces. They, due to this fact, start at their "mirror points" and will travel simplest upward. As they achieve this, the "mirror effect" transforms their directions of movement, from perpendicular to the box line to a cone round it, which gradually narrows down, changing into more and more parallel at massive distances where the box is way weaker.

Auroral events of historical importance

The discovery of a 1770 Japanese diary in 2017 depicting auroras above the historical Japanese capital of Kyoto advised that the storm could have been 7% greater than the Carrington tournament, which affected telegraph networks.[67][68]

The auroras that resulted from the "great geomagnetic storm" on each 28 August and a couple of September 1859, alternatively, are thought to be the maximum spectacular in fresh recorded historical past. In a paper to the Royal Society on 21 November 1861, Balfour Stewart described each auroral events as documented by means of a self-recording magnetograph at the Kew Observatory and established the connection between the 2 September 1859 auroral typhoon and the Carrington-Hodgson flare event when he noticed that "It is not impossible to suppose that in this case our luminary was taken in the act."[69] The moment auroral tournament, which passed off on 2 September 1859 because of the exceptionally intense Carrington-Hodgson white gentle solar flare on 1 September 1859, produced auroras, so fashionable and extraordinarily bright, that they were seen and reported in revealed scientific measurements, send logs, and newspapers right through the United States, Europe, Japan, and Australia. It was once reported by The New York Times that in Boston on Friday 2 September 1859 the aurora was once "so brilliant that at about one o'clock ordinary print could be read by the light".[70] One o'clock EST time on Friday 2 September, would have been 6:00 GMT and the self-recording magnetograph at the Kew Observatory was recording the geomagnetic storm, which used to be then one hour old, at its complete intensity. Between 1859 and 1862, Elias Loomis revealed a series of nine papers on the Great Auroral Exhibition of 1859 in the American Journal of Science where he amassed worldwide stories of the auroral tournament.[7]

That aurora is believed to have been produced by means of considered one of the most intense coronal mass ejections in history. It could also be notable for the incontrovertible fact that it's the first time where the phenomena of auroral activity and electricity were unambiguously linked. This perception was made imaginable not handiest because of clinical magnetometer measurements of the era, but additionally as a result of a good portion of the 125,000 miles (201,000 km) of telegraph traces then in service being significantly disrupted for lots of hours throughout the hurricane. Some telegraph strains, alternatively, seem to have been of the appropriate period and orientation to supply a enough geomagnetically precipitated current from the electromagnetic field to allow for persevered communication with the telegraph operator energy supplies switched off.[71] The following conversation occurred between two operators of the American Telegraph Line between Boston and Portland, Maine, on the evening of 2 September 1859 and reported in the Boston Traveler:

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 the use of no battery energy in any respect and dealing only with the present caused by the aurora, and it used to be mentioned that this used to be the first time on record that more than a phrase or two was once transmitted in such way.[70] Such events resulted in the common conclusion that

The impact of the aurorae on the electric telegraph is generally to extend or diminish the electric current generated in operating the wires. Sometimes it entirely neutralizes them, so that, in effect, no fluid [present] is discoverable in them. The aurora borealis seems to be composed of a mass of electrical subject, comparable to in each appreciate, that generated by means of the electric galvanic battery. The currents from it alternate coming on the wires, and then disappear the mass of the aurora rolls from the horizon to the zenith.[72]

Historical theories, superstition and mythology

An aurora was once described through the Greek explorer Pytheas in the 4th century BC.[73]Seneca wrote about auroras in the first guide of his Naturales Quaestiones, classifying them, as an example as pithaei ('barrel-like'); chasmata ('chasm'); pogoniae ('bearded'); cyparissae ('like cypress timber'), and describing their manifold colors. He wrote about whether or not they were above or underneath the clouds, and recalled that below Tiberius, an aurora formed above the port city of Ostia that was once so intense and purple that a cohort of the military, stationed within sight for fire accountability, galloped to the rescue.[74] It has been advised that Pliny the Elder depicted the aurora borealis in his Natural History, when he refers to trabes, chasma, 'falling crimson flames' and 'daylight in the night'.[75]

The historical past of China has wealthy, and most likely the oldest, records of the aurora borealis. On an autumn round 2000 BC, in line with a legend, a tender girl named Fubao used to be sitting on my own in the wasteland by way of a bay, when all at once a "magical band of light" appeared like "moving clouds and flowing water", turning into a bright halo around the Big Dipper, which cascaded a light silver brilliance, illuminating the earth and making shapes and shadows appear alive. Moved through this sight, Fubao turned into pregnant and gave birth to a son, the Emperor Xuanyuan, identified legendarily as the initiator of Chinese tradition and the ancestor of all Chinese other people. In the Shanhaijing, a creature named 'Shilong' is described to be like a red dragon shining in the evening sky with a body 1000 miles long. In precedent days, the Chinese did not have a hard and fast phrase for the aurora, so it was once named consistent with the different shapes of the aurora, reminiscent of "Sky Dog ("天狗")", "Sword/Knife Star ("刀星")", "Chiyou banner ("蚩尤旗")", "Sky's Open Eyes ("天开眼")", and "Stars like Rain ("星陨如雨")".

In Japanese folklore, pheasants had been regarded as messengers from heaven. However, researchers from Japan's Graduate University for Advanced Studies and National Institute of Polar Research claimed in March 2020 that crimson pheasant tails witnessed across the evening sky over Japan in 620 A.D., might be a red aurora produced right through a magnetic hurricane.[76]

The Aboriginal Australians related auroras (which can be principally low on the horizon and predominantly red) with fireplace.

In the traditions of Aboriginal Australians, the Aurora Australis is often associated with fireplace. For example, the Gunditjmara other folks of western Victoria known as auroras puae buae ('ashes'), whilst the Gunai people of jap Victoria perceived auroras as bushfires in the spirit global. The Dieri people of South Australia say that an auroral display is kootchee, an evil spirit growing a large hearth. Similarly, the Ngarrindjeri other folks of South Australia confer with auroras seen over Kangaroo Island as the campfires of spirits in the 'Land of the Dead'. Aboriginal other people in southwest Queensland imagine the auroras to be the fires of the Oola Pikka, ghostly spirits who spoke to the other people thru auroras. Sacred regulation forbade anyone apart from male elders from observing or interpreting the messages of ancestors they believed had been transmitted through an aurora.[77]

Bulfinch's Mythology relates that in Norse mythology, the armour of the Valkyrior "sheds a strange flickering light, which flashes up over the northern skies, making what Men call the 'aurora borealis', or 'Northern Lights' ".[78] There seems to be no evidence in Old Norse literature to substantiate this statement.[79] The first Old Norse account of norðrljós is located in the Norwegian chronicle Konungs Skuggsjá from AD 1230. The chronicler has heard about this phenomenon from compatriots returning from Greenland, and he provides three conceivable explanations: that the ocean used to be surrounded by means of vast fires; that the sun flares could reach around the international to its evening aspect; or that glaciers may store power in order that they eventually become fluorescent.[80]

Walter William Bryant wrote in his ebook Kepler (1920) that Tycho Brahe "seems to have been something of a homœopathist, for he recommends sulfur to cure infectious diseases 'brought on by the sulphurous vapours of the Aurora Borealis.'"[81]

In 1778, Benjamin Franklin theorized in his paper Aurora Borealis, Suppositions and Conjectures in opposition to forming an Hypothesis for its Explanation that an aurora used to be caused by way of a focus of electrical payment in the polar areas intensified by the snow and moisture in the air:[82][83][84]

May no longer then the great amount of electricity introduced into the polar areas via the clouds, which can be condens'd there, and fall in snow, which electrical energy would enter the earth, but can not penetrate the ice; may it now not, I say (as a bottle overcharged) wreck thro' that low atmosphere and run alongside in the vacuum over the air against the equator, diverging as the levels of longitude enlarge, strongly seen the place densest, and becoming less seen because it extra diverges; till it finds a passage to the earth in more temperate climates, or is mingled with the upper air?

— Benjamin Franklin

Observations of the rhythmic motion of compass needles due to the influence of an aurora were showed in the Swedish city of Uppsala by means of Anders Celsius and Olof Hiorter. In 1741, Hiorter used to be in a position to hyperlink massive magnetic fluctuations with an aurora being observed overhead. This proof helped to make stronger their concept that 'magnetic storms' are liable for such compass fluctuations.[85]

Church's 1865 painting Aurora Borealis

Various Native American myths encompass the spectacle. The European explorer Samuel Hearne traveled with Chipewyan Dene in 1771 and recorded their views on the ed-thin ('caribou'). According to Hearne, the Dene other people saw the resemblance between an aurora and the sparks produced when caribou fur is stroked. They believed that the lighting fixtures were the spirits in their departed buddies dancing in the sky, and when they shone brightly it supposed that their deceased pals had been very happy.[86]

During the night after the Battle of Fredericksburg, an aurora was viewed from the battlefield. The Confederate Army took this as an indication that God used to be on their facet, as the lights were hardly ever seen to this point south. The painting Aurora Borealis by means of Frederic Edwin Church is extensively interpreted to represent the conflict of the American Civil War.[87]

A mid Nineteenth-century British supply says auroras had been a unprecedented prevalence prior to the 18th-century.[88] It quotes Halley as pronouncing that earlier than the aurora of 1716, no such phenomenon have been recorded for greater than 80 years, and none of any end result since 1574. It says no appearance is recorded in the Transactions of the French Academy of Sciences between 1666 and 1716. And that one aurora recorded in Berlin Miscellany for 1797 used to be known as a very uncommon tournament. One observed in 1723 at Bologna was once mentioned to be the first ever considered there. Celsius (1733) states the oldest citizens of Uppsala thought the phenomenon an excellent rarity prior to 1716. The period between roughly 1645 to 1715 corresponds to the Maunder minimal in sunspot process.

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 the city searching for buyers.

It used to be the Norwegian scientist Kristian Birkeland who, in the early 1900s, laid the basis for our current figuring out of geomagnetism and polar auroras.

Non-terrestrial auroras

See also: Magnetosphere of Jupiter § Aurorae Jupiter aurora; the a ways left shiny spot connects magnetically to Io; the spots at the bottom of the image result in Ganymede and Europa. An aurora high above the northern part of Saturn; image taken by means of the Cassini spacecraft. A film shows photographs from Eighty one hours of observations of Saturn's aurora

Both Jupiter and Saturn have magnetic fields that are stronger than Earth's (Jupiter's equatorial field energy is 4.3 Gauss, in comparison to 0.3 Gauss for Earth), and each have in depth radiation belts. Auroras were seen on each fuel planets, maximum clearly the usage of the Hubble Space Telescope, and the Cassini and Galileo spacecraft, as well as on Uranus and Neptune.[89]

The aurorae on Saturn appear, like Earth's, to be powered by the solar wind. However, Jupiter's aurorae are more complicated. The Jupiter's main auroral oval is associated with the plasma produced by way of the volcanic moon, Io and the shipping of this plasma inside of the planet's magnetosphere. An uncertain fraction of Jupiter's aurorae are powered by the photo voltaic wind. In addition, the moons, particularly Io, also are powerful sources of aurora. These stand up from electrical currents along box traces ("field aligned currents"), generated by means of a dynamo mechanism because of the relative movement between the rotating planet and the transferring moon. Io, which has active volcanism and an ionosphere, is a particularly robust source, and its currents additionally generate radio emissions, which were studied since 1955. Using the Hubble Space Telescope, auroras over Io, Europa and Ganymede have all been noticed.

Auroras have also been noticed on Venus and Mars. Venus has no magnetic box and so Venusian auroras seem as shiny and diffuse patches of various shape and depth, infrequently distributed over the complete disc of the planet.[90] A Venusian aurora originates when electrons from the photo voltaic wind collide with the night-side surroundings.

An aurora was once detected on Mars, on 14 August 2004, via the SPICAM software aboard Mars Express. The aurora used to be situated at Terra Cimmeria, in the region of 177° East, 52° South. The total size of the emission area was about 30 km across, and most likely about 8 km high. By analyzing a map of crustal magnetic anomalies compiled with data from Mars Global Surveyor, scientists seen that the area of the emissions corresponded to a space where the strongest magnetic field is localized. This correlation indicated that the foundation of the light emission was a flux of electrons shifting alongside the crust magnetic strains and exciting the higher setting of Mars.[89][91]

In September 2020, cometary auroras were introduced on the comet 67P/Churyumov-Gerasimenko via more than one instruments on the Rosetta spacecraft.[92][93] The auroras had been observed at far-ultraviolet wavelengths. Coma observations revealed atomic emissions of hydrogen and oxygen brought about via the photodissociation (not photoionization, like in terrestrial auroras) of water molecules in the comet's coma.[93] The interaction of accelerated electrons from the solar wind with gasoline particles in the coma is answerable for the aurora.[93] Since comet 67P has no magnetic box, the aurora is diffusely spread round the comet.[93]

Exoplanets, such as sizzling Jupiters, have been recommended to experience ionization in their upper atmospheres and generate an aurora modified through climate in their turbulent tropospheres.[94] However, there is no present detection of an exoplanet aurora.

The first ever extra-solar auroras have been came upon in July 2015 over the brown dwarf star LSR J1835+3259.[95] The basically purple aurora was discovered to be a million times brighter than the Northern Lights, a result of the charged particles interacting with hydrogen in the atmosphere. It has been speculated that stellar winds is also stripping off material from the surface of the brown dwarf to provide their own electrons. Another conceivable cause of the auroras is that an as-yet-undetected body around the dwarf celebrity is throwing off subject matter, as is the case with Jupiter and its moon Io.[96]

See additionally

Airglow Aurora (heraldry) Heliophysics List of plasma physics articles List of photo voltaic storms Paschen's legislation Space twister Space climate

Notes

^ The name "auroras" is now the more commonplace plural of "aurora", on the other hand aurorae is the authentic Latin plural and is often utilized by scientists; in some contexts, aurora is an uncountable noun, a couple of sightings being known as "the aurora". Modern genre guides counsel that the names of meteorological phenomena, similar to aurora borealis, be uncapitalized.[1]

References

^ .mw-parser-output cite.quotationfont-style:inherit.mw-parser-output .citation qquotes:"\"""\"""'""'".mw-parser-output .id-lock-free a,.mw-parser-output .citation .cs1-lock-free abackground:linear-gradient(transparent,clear),url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat.mw-parser-output .id-lock-limited a,.mw-parser-output .id-lock-registration a,.mw-parser-output .quotation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration abackground:linear-gradient(transparent,clear),url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")appropriate 0.1em middle/9px no-repeat.mw-parser-output .id-lock-subscription a,.mw-parser-output .citation .cs1-lock-subscription abackground:linear-gradient(clear,clear),url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")appropriate 0.1em heart/9px no-repeat.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcoloration:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-ws-icon abackground:linear-gradient(transparent,clear),url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")correct 0.1em middle/12px no-repeat.mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:none;padding:inherit.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-maintdisplay:none;coloration:#33aa33;margin-left:0.3em.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em.mw-parser-output .citation .mw-selflinkfont-weight:inherit"University of Minnesota Style Manual". .umn.edu. 18 July 2007. Archived from the unique on 22 July 2010. Retrieved 5 August 2010. ^ "Simultaneous ground and satellite observations of an isolated proton arc at sub-auroral latitudes". Journal of Geophysical Research. 2007. Retrieved 5 August 2015. ^ Harper, Douglas (ed.). "Aurora". Online Etymology Dictionary. Retrieved 14 February 2019. ^ "The Odyssey ca. 500 B.C. by Homer (translated by Samuel Butler 1900); online at Internet Classics Archive (Retrieved 15 February 2021)". 1993. ^ a b Feldstein, Y. I. (2011). "A Quarter Century with the Auroral Oval". EOS. 67 (40): 761. Bibcode:1986EOSTr..67..761F. doi:10.1029/EO067i040p00761-02. ^ Bruzek, A.; Durrant, C. J. (2012). Illustrated Glossary for Solar and Solar-Terrestrial Physics. Springer Science & Business Media. p. 190. ISBN 978-94-010-1245-4. ^ a b See: Loomis, Elias (November 1859). "The great auroral exhibition of August 28 to September, 1859". The American Journal of Science. second collection. 28: 385–408. Loomis, Elias (January 1860). "The great auroral exhibition of August 28 to September 4, 1859—2nd article". The American Journal of Science. 2d sequence. 29: 92–97. Loomis, Elias (February 1860). "The great auroral exhibition of August 28 to September 4, 1859—3rd article". The American Journal of Science. second sequence. 29: 249–266. Loomis, Elias (May 1860). "The great auroral exhibition of August 28 to September 4, 1859—4th article". The American Journal of Science. second sequence. 29: 386–399. 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 sequence. 30: 79–100. 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. Loomis, Elias (July 1861). "The great auroral exhibition of August 28 to September 4, 1859—7th article". The American Journal of Science. 2nd collection. 32: 71–84. 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. 2d collection. 32: 318–335. 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 sequence. 34: 34–45. ^ Fritz, Hermann (1881). Das Polarlicht [The Aurora] (in German). Leipzig, Germany: F. A. Brockhaus. ^ 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. ^ "Current Auroral Oval". SpaceWeather. Retrieved 19 December 2014. ^ Siscoe, G. L. (1986). "An historical footnote on the origin of 'aurora borealis'". History of Geophysics: Volume 2. History of Geophysics: Volume 2. Series: History of Geophysics. History of Geophysics. 2. pp. 11–14. Bibcode:1986HGeo....2...11S. doi:10.1029/HG002p0011. ISBN 978-0-87590-276-0. ^ Guiducci, Mario; Galilei, Galileo (1619). Discorso delle Comete [Discourse on Comets] (in Italian). Firenze (Florence), Italy: Pietro Cecconcelli. p. 39. On p. 39, Galileo explains that auroras are due to daylight reflecting from skinny, excessive 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'll have viewed, greater than as soon as, the sky in the night hours, in portions towards the north, illuminated in some way that the clear [sky] does not yield to the brighter aurora, far from the rising of the solar; an impact that, via my pondering, has no different foundation than being a part of the vaporous air that surrounds the Earth, for some reason thinner than usual, which, being sublimated far more than same old, has risen above the cone of the Earth's shadow, in order that its higher section, being struck by way of the sun['s mild], has been able to reflect its splendor and to form this aurora borealis.) ^ Østgaard, N.; Mende, S. B.; Frey, H. U.; Sigwarth, J. B.; Åsnes, A.; Weygand, J. M. (2007). "Auroral conjugacy studies based on global imaging". Journal of Atmospheric and Solar-Terrestrial Physics. 69 (3): 249. Bibcode:2007JASTP..69..249O. doi:10.1016/j.jastp.2006.05.026. ^ Frey, H. U. (2007). "Localized aurora beyond the auroral oval". Rev. Geophys. 45 (1): RG1003. Bibcode:2007RvGeo..45.1003F. doi:10.1029/2005RG000174. ^ Stamper, J.; Lockwood, M.; Wild, M. N. (December 1999). "Solar causes of the long-term increase in geomagnetic activity" (PDF). J. Geophys. Res. 104 (A12): 28, 325–28, 342. Bibcode:1999JGR...10428325S. doi:10.1029/1999JA900311. ^ Papitashvili, V. O.; Papitashva, N. E.; King, J. H. (September 2000). "Solar cycle effects in planetary geomagnetic activity: Analysis of 36-year long OMNI dataset" (PDF). Geophys. Res. Lett. 27 (17): 2797–2800. Bibcode:2000GeoRL..27.2797P. doi:10.1029/2000GL000064. hdl:2027.42/94796. ^ Østgaard, N. (2003). "Observations of non-conjugate theta aurora". Geophysical Research Letters. 30 (21): 2125. Bibcode:2003GeoRL..30.2125O. doi:10.1029/2003GL017914. ^ Størmer, Carl (1946). "Frequency of 12,330 measured heights of aurora from southern Norway in the years 1911–1944". Terrestrial Magnetism and Atmospheric Electricity. 51 (4): 501–504. Bibcode:1946TeMAE..51..501S. doi:10.1029/te051i004p00501. ^ "News and information about meteor showers, solar flares, auroras, and near-Earth asteroids". SpaceWeather.com. Archived from the unique on 4 August 2010. Retrieved 5 August 2010. ^ "Astronomical photographs from David Malin Images". davidmalin.com. Retrieved 3 August 2010. ^ "NOAA POES Auroral Activity". swpc.noaa.gov. Archived from the original on 28 July 2010. Retrieved 3 August 2010. ^ "What's up in space: Auroras Underfoot". SpaceWeather.com. Archived from the authentic on 17 July 2011. Retrieved 26 July 2011. ^ Aurora image (JPG) ^ Clark, Stuart (2007). "Astronomical fire: Richard Carrington and the solar flare of 1859". Endeavour. 31 (3): 104–109. doi:10.1016/j.endeavour.2007.07.004. PMID 17764743. ^ Zhu, L.; Schunk, R. W.; Sojka, J. J. (1997). "Polar cap arcs: A review". Journal of Atmospheric and Solar-Terrestrial Physics. 59 (10): 1087. Bibcode:1997JASTP..59.1087Z. doi:10.1016/S1364-6826(96)00113-7. ^ a b A, Brekke; A, Egeland (1994). The Northern Lights. Grøndahl and Dreyer, Oslo. p. 137. ISBN 978-82-504-2105-9. ^ a b Yahnin, A. G.; Sergeev, V. A.; Gvozdevsky, B. B.; Vennerstrøm, S. (1997). "Magnetospheric source region of discrete auroras inferred from their relationship with isotropy boundaries of energetic particles". Annales Geophysicae. 15 (8): 943. Bibcode:1997AnGeo..15..943Y. doi:10.1007/s00585-997-0943-z. ^ Thomson, E. (1917). "Inferences concerning auroras". Proceedings of the National Academy of Sciences of the United States of America. 3 (1): 1–7. Bibcode:1917PNAS....3....1T. doi:10.1073/pnas.3.1.1. PMC 1091158. PMID 16586674. ^ "Windows to the Universe – Auroral colors and spectra". ^ a b "NASA's MAVEN Orbiter Detects Ultraviolet Aurora on Mars | Space Exploration | Sci-News.com". sci-news.com. Retrieved 16 August 2015. ^ "Aurora Borealis". dapep.org. Retrieved 16 August 2015. ^ Partamies, N.; Whiter, D.; Kadokura, A.; Kauristie, K.; Tyssøy, H. Nesse; Massetti, S.; Stauning, P.; Raita, T. (2017). "Occurrence and average behavior of pulsating aurora". Journal of Geophysical Research: Space Physics. 122 (5): 5606–5618. Bibcode:2017JGRA..122.5606P. doi:10.1002/2017JA024039. ISSN 2169-9402. ^ Gurnett, D.A. (1974). "The Earth as a radio source". Journal of Geophysical Research. 79 (28): 4227. Bibcode:1974JGR....79.4227G. doi:10.1029/JA079i028p04227. ^ Anderson, Okay.A. (1960). "Balloon observations of X-rays in the auroral zone". Journal of Geophysical Research. 65 (2): 551–564. Bibcode:1960JGR....65..551A. doi:10.1029/jz065i002p00551. ^ "Auroras Make Weird Noises, and Now We Know Why". 27 June 2016. Retrieved 28 June 2016. ^ "News: Acoustics researcher finds explanation for auroral sounds". 21 June 2016. Retrieved 28 June 2016. ^ American Geophysical Union (20 August 2018). "New kind of aurora is not an aurora at all". Physorg.com. Retrieved 21 August 2018. ^ Andrews, Robin George (3 May 2019). "Steve the odd 'aurora' revealed to be two sky shows in one". National Geographic. National Geographic. Retrieved 4 May 2019. ^ a b Nishimura, Y.; Gallardo‐Lacourt, B.; Zou, Y.; Mishin, E.; Knudsen, D.J.; Donovan, E.F.; Angelopoulos, V.; Raybell, R. (16 April 2019). "Magnetospheric signatures of STEVE: Implication for the magnetospheric energy source and inter‐hemispheric conjugacy". Geophysical Research Letters. 46 (11): 5637–5644. Bibcode:2019GeoRL..46.5637N. doi:10.1029/2019GL082460. ^ Lipuma, Lauren. "Scientists discover what powers celestial phenomenon STEVE". AGU News. American Geophysical Union. Retrieved 4 May 2019. ^ Saner, Emine (19 March 2018). "'Steve': the mystery purple aurora that rivals the northern lights". the Guardian. Retrieved 22 March 2018. ^ Burch, J L (1987). Akasofu S-I and Y Kamide (ed.). The solar wind and the Earth. D. Reidel. p. 103. ISBN 978-90-277-2471-7. ^ McIlwain, C E (1960). "Direct Measurement of Particles Producing Visible Auroras". Journal of Geophysical Research. 65 (9): 2727. Bibcode:1960JGR....65.2727M. doi:10.1029/JZ065i009p02727. ^ Reiff, P. H.; Collin, H. L.; Craven, J. D.; Burch, J. L.; Winningham, J. D.; Shelley, E. G.; Frank, L. A.; Friedman, M. A. (1988). "Determination of auroral electrostatic potentials using high- and low-altitude particle distributions". Journal of Geophysical Research. 93 (A7): 7441. Bibcode:1988JGR....93.7441R. doi:10.1029/JA093iA07p07441. ^ Bryant, D. A.; Collin, H. L.; Courtier, G. M.; Johnstone, A. D. (1967). "Evidence for Velocity Dispersion in Auroral Electrons". Nature. 215 (5096): 45. Bibcode:1967Natur.215...45B. doi:10.1038/215045a0. S2CID 4173665. ^ "Ultraviolet Waves". Archived from the unique on 27 January 2011. ^ Schield, M. A.; Freeman, J. W.; Dessler, A. J. (1969). "A Source for Field-Aligned Currents at Auroral Latitudes". Journal of Geophysical Research. 74 (1): 247–256. Bibcode:1969JGR....74..247S. doi:10.1029/JA074i001p00247. ^ Armstrong, J. C.; Zmuda, A. J. (1973). "Triaxial magnetic measurements of field-aligned currents at 800 kilometers in the auroral region: Initial results". Journal of Geophysical Research. 78 (28): 6802–6807. Bibcode:1973JGR....78.6802A. doi:10.1029/JA078i028p06802. ^ Birkeland, Kristian (1908). The Norwegian Aurora Polaris Expedition 1902–1903. New York: Christiania (Oslo): H. Aschehoug & Co. p. 720. out-of-print, complete textual content on-line ^ Crooker, N. U.; Feynman, J.; Gosling, J. T. (1 May 1977). "On the high correlation between long-term averages of solar wind speed and geomagnetic activity". Journal of Geophysical Research. 82 (13): 1933. Bibcode:1977JGR....82.1933C. doi:10.1029/JA082i013p01933. ^ Alaska.edu Archived 20 December 2006 at the Wayback Machine, Solar wind forecast from a University of Alaska web site ^ "NASA – NASA and World Book". Nasa.gov. 7 February 2011. Archived from the original on 5 September 2005. Retrieved 26 July 2011. ^ Shue, J.-H; Chao, J. K.; Fu, H. C.; Russell, C. T.; Song, P.; Khurana, Okay. K.; Singer, H. J. (May 1997). "A new functional form to study the solar wind control of the magnetopause size and shape". J. Geophys. Res. 102 (A5): 9497–9511. Bibcode:1997JGR...102.9497S. doi:10.1029/97JA00196. ^ Lyons, L. R.; Kim, H.-J.; Xing, X.; Zou, S.; Lee, D.-Y.; Heinselman, C.; Nicolls, M. J.; Angelopoulos, V.; Larson, D.; McFadden, J.; Runov, A.; Fornacon, K.-H. (2009). "Evidence that solar wind fluctuations substantially affect global convection and substorm occurrence". J. Geophys. Res. 114 (A11306): 1–14. Bibcode:2009JGRA..11411306L. doi:10.1029/2009JA014281. ^ "NASA – THEMIS Satellites Discover What Triggers Eruptions of the Northern Lights". Nasa.gov. Archived from the authentic on 29 June 2011. Retrieved 26 July 2011. ^ Angelopoulos, V.; McFadden, J. P.; Larson, D.; Carlson, C. W.; Mende, S. B.; Frey, H.; Phan, T.; Sibeck, D. G.; Glassmeier, Okay.-H.; Auster, U.; Donovan, E.; Mann, I. R.; Rae, I. J.; Russell, C. T.; Runov, A.; Zhou, X.-Z.; Kepko, L. (2008). "Tail Reconnection Triggering Substorm Onset". Science. 321 (5891): 931–5. Bibcode:2008Sci...321..931A. doi:10.1126/science.1160495. PMID 18653845. S2CID 206514133. ^ "Network community structure of substorms using SuperMAG magnetometers, L. Orr, S. C. Chapman, J. W. Gjerloev & W. Guo". Nature Communications. Archived from the unique on 29 March 2021. Retrieved 26 March 2021. ^ Bryant, Duncan (1998). Electron-Acceleration-in-the-Aurora-and-Beyond. Bristol & Philadelphia: Institute of Physics Publishing Ltd. p. 163. ISBN 978-0750305334. ^ Evans, D S (1975). Hot Plasma in the Magnetosphere. New York and London: Plenum Press. pp. 319–340. ISBN 978-0306337000. ^ Boström, Rolf "Observations of weak double layers on auroral field lines" (1992) IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. 20, no. 6, pp. 756–763 ^ Ergun, R. E., et al. "Parallel electric fields in the upward current region of the aurora: Indirect and direct observations" (2002) Physics of Plasmas, Volume 9, Issue 9, pp. 3685–3694 ^ Carlson, C.W., R.F.Pfaff and J.G.Watzin (June 1998). "The Fast Auroral SnapshoT (FAST) mission". Geophysical Research Letters. 25 (12): 2013–2016. Bibcode:1998GeoRL..25.2013C. doi:10.1029/98GL01592. ^ "Lev Davidovich Landau". historical past.mcs.st-andrews.ac.united kingdom. ^ Cairns, R A (1993). Dendy, R O (ed.). Plasma Physics:An Introductory Course. Cambridge University Press. pp. 391–410. ISBN 978-0521433099. ^ Bryant, D A; Perry, C H (1995). "Velocity-space distributions of wave-accelerated auroral electrons". Journal of Geophysical Research. 100 (A12): 23, 711–23, 725. Bibcode:1995JGR...10023711B. doi:10.1029/95ja00991. ^ Alfvén, Hannes (3 October 1942). "Existence of electromagnetic-hydrodynamic waves". Nature. 150 (3805): 405–406. Bibcode:1942Natur.150..405A. doi:10.1038/150405d0. S2CID 4072220. ^ Frost, Natasha (4 October 2017). "1770 Kyoto Diary". Atlas Obscura. Retrieved 13 October 2017. ^ Kataoka, Ryuho; Iwahashi, Kiyomi (17 September 2017). "Inclined zenith aurora over Kyoto on 17 September 1770: Graphical evidence of extreme magnetic storm". Space Weather. 15 (10): 1314–1320. Bibcode:2017SpWea..15.1314K. doi:10.1002/2017SW001690. ^ Stewart, Balfour (1861). "On the Great Magnetic Disturbance of 28 August to 7 September 1859, as Recorded by Photography at the Kew Observatory". Philosophical Transactions of the Royal Society of London. 151: 423–430. doi:10.1098/rstl.1861.0023. See p. 428. ^ a b Green, J; Boardsen, S; Odenwald, S; Humble, J; Pazamickas, Okay (2006). "Eyewitness reports of the great auroral storm of 1859". Advances in Space Research. 38 (2): 145–54. Bibcode:2006AdSpR..38..145G. doi:10.1016/j.asr.2005.12.021. hdl:2060/20050210157. ^ Loomis, Elias (January 1860). "The great auroral exhibition of August 28 to September 4, 1859—2nd article". The American Journal of Science. second series. 29: 92–97. ^ The British Colonist, Vol. 2 No. 56, 19 October 1859, p. 1, accessed online at BritishColonist.ca Archived 31 August 2009 at the Wayback Machine, on 19 February 2009. ^ Macleod, Explorers: Great Tales of Adventure and Endurance, p.21. ^ Clarke, J.,Physical Science in the time of Nero p.39-41, London, Macmillan, (1910), accessed online on 1 January 2017. ^ Bostock, J. and Riley, H.T., The Natural History of Pliny: Volume II, London, Bohn (1855), accessed on-line at [1], on 1 January 2017. ^ "Modern science reveals ancient secret in Japanese literature". phys.org. 30 March 2020. ^ Hamacher, D.W. (2013). "Aurorae in Australian Aboriginal Traditions" (PDF). Journal of Astronomical History and Heritage. 16 (2): 207–219. arXiv:1309.3367. Bibcode:2013JAHH...16..207H. Archived from the original (PDF) on 20 October 2013. Retrieved 19 October 2013. ^ "Bullfinch's Mythology". Mythome.org. 10 February 1996. Archived from the authentic on 14 February 2011. Retrieved 5 August 2010. ^ "The Aurora Borealis and the Vikings". Vikinganswerlady.com. Retrieved 5 August 2010. ^ "Norrsken history". Irf.se. 12 November 2003. Archived from the original on 21 July 2011. Retrieved 26 July 2011. ^ Walter William Bryant, Kepler. Macmillan Co. (1920) p.23. ^ The unique English text of Benjamin Franklin's article on the reason behind auroras is available at: U.S. National Archives: Founders Online ^ A translation into French of Franklin's article used to be learn 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. ^ Goodman, N., ed. (2011). The Ingenious Dr. Franklin: Selected Scientific Letters of Benjamin Franklin. Philadelphia: University of Pennsylvania Press. p. 3. ISBN 978-0-8122-0561-9. ^ J. Oschman (2016), Energy Medicine: The Scientific Basis (Elsevier, Edinburgh) p. 275. ^ 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. ^ "Aurora Borealis at the American Art Museum". ^ The National Cyclopaedia of Useful Knowledge, Vol.II, (1847), London, Charles Knight, p.496 ^ a b "ESA Portal – Mars Express discovers auroras on Mars". Esa.int. 11 August 2004. Retrieved 5 August 2010. ^ Phillips, J. L.; Stewart, A. I. F.; Luhmann, J. G. (1986). "The Venus ultraviolet aurora: Observations at 130.4 nm". Geophysical Research Letters. 13 (10): 1047–1050. doi:10.1029/GL013i010p01047. ISSN 1944-8007. ^ "Mars Express Finds Auroras on Mars". Universe Today. 18 February 2006. Retrieved 5 August 2010. ^ "Comet Chury's ultraviolet aurora". Portal. 21 September 2020. Retrieved 17 January 2021. ^ a b c d Galand, M.; Feldman, P. D.; Bockelée-Morvan, D.; Biver, N.; Cheng, Y.-C.; Rinaldi, G.; Rubin, M.; Altwegg, K.; Deca, J.; Beth, A.; Stephenson, P. (21 September 2020). "Far-ultraviolet aurora identified at comet 67P/Churyumov-Gerasimenko". Nature Astronomy. 4 (11): 1084–1091. doi:10.1038/s41550-020-1171-7. hdl:10044/1/82183. ISSN 2397-3366. ^ Helling, Christiane; Rimmer, Paul B. (23 September 2019). "Lightning and charge processes in brown dwarf and exoplanet atmospheres". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 377 (2154): 20180398. doi:10.1098/rsta.2018.0398. PMC 6710897. ^ O'Neill, Ian (29 July 2015). "Monstrous Aurora Detected Beyond our Solar System". Discovery. Retrieved 29 July 2015. ^ Q. Choi, Charles (29 July 2015). "First Alien Auroras Found, Are 1 Million Times Brighter Than Any on Earth". area.com. Retrieved 29 July 2015.

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Wikimedia Commons has media associated with Aurora. Wikiquote has quotations related to: Aurora Wikivoyage has a travel information for Northern Lights.Aurora forecast – Will there be northern lighting fixtures? Current international map showing the chance of seen aurora Aurora – Forecasting Official MET aurora forecasting in Iceland Aurora Borealis – Predicting Solar Terrestrial Data – Online Converter – Northern Lights Latitude. Aurora Service Europe – Aurora forecasts for Europe. Live Northern Lights webstreamMultimedia 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. Aurora Photo Gallery – "Full-Sky Aurora" over Eastern Norway. December 2011. Videos and Photos – Auroras at Night. Video (04:49) – Aurora Borealis – How The Northern Lights Are Created. Video (47:40) – Northern Lights – Documentary. Video (5:00) – Northern lighting fixtures video in real time Video (01:42) – Northern Lights – Story of Geomagnetc Storm (Terschelling Island – 6/7 April 2000). Video (01:56) (Time-Lapse) − Auroras – Ground-Level View from Finnish Lapland 2011. Video (02:43) (Time-Lapse) − Auroras – Ground-Level View from Tromsø, Norway. 24 November 2010. Video (00:27) (Time-Lapse) – Earth and Auroras – Viewed from The International Space Station.vteMagnetosphericsSubmagnetosphere Atmospheric stream Aurora Earth's magnetic field Geosphere Jet circulate Polar windEarth's magnetosphere Birkeland current Bow surprise Ionosphere Magnetopause Magnetosheath Magnetosphere Magnetosphere chronology Magnetosphere particle movement Plasmasphere Ring present Van Allen radiation beltSolar wind Coronal cloud Coronal mass ejection Solar flare Geomagnetic typhoon Heliosphere Interplanetary magnetic box Heliospheric present sheet Heliopause Solar particle tournament Space climate Space weatherSatellites Full listing Arase (2016) Cluster II Double Star Geotail IMAGE MMS (2015) Polar THEMIS Van Allen Probes WindResearch tasks EISCAT HAARP SHARE Unwin Radar SuperDARN Sura Ionospheric Heating FacilityOther magnetospheres Hermian Lunar Jovian Ganymedian Saturnian Uranian NeptunianRelated subjects Flux tube Gas torus Lunar swirls Ring programs Jupiter Saturn Uranus Neptune Authority keep watch over GND: 4130058-0 LCCN: sh85009555 NDL: 00567224 Retrieved from "https://en.wikipedia.org/w/index.php?title=Aurora&oldid=1015475425"

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