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97-533: Northern lights most commonly refers to the aurora borealis , a natural light display in Earth's sky. ( The ) Northern Light ( s ) may also refer to: Aurora borealis An aurora ( pl. aurorae or auroras ), also commonly known as the northern lights ( aurora borealis ) or southern lights ( aurora australis ), is a natural light display in Earth 's sky, predominantly seen in high-latitude regions (around

194-654: A dozen of "racial" categories created in 18th century Hispanic America , with notorious examples being castizo , morisco and cambujo . In Brazil, about 190 "racial" categories were detected by the Census of 1976. A study conducted on 218 individuals in 2010 by the Argentine geneticist Daniel Corach , has established that the genetic map of Argentina is composed of 79% different European ethnicities (mainly Spanish and Italian ethnicities), 18% of different indigenous ethnicities, and 4.3% of African ethnic groups, in which 63.6% of

291-401: 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. 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

388-755: A majority in Paraguay . Native Americans make up 3% of the population, living in communities in Araucanía region in Chile. Mulattoes (people of European and African ancestry) mostly in Uruguay (0.2%), and Asians (1.0%), mostly in Argentina, the remaining 1.2%. There is also a strong Arab presence in the Southern Cone, with people of full or at least partial Arab ancestry being 5% of the population of Uruguay and Chile , 9.8% of

485-432: A particle depends on the particle's pitch angle : the angle between its direction of motion and the local magnetic field. An aurora is created by processes that decrease the pitch angle of many individual electrons, freeing them from the magnetic trap and causing them to hit the atmosphere. In the case of diffuse auroras, the electron pitch angles are altered by their interaction with various plasma waves . Each interaction

582-510: A southward component of the IMF, which can then directly connect to the high latitude geomagnetic field lines. 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

679-407: A surfer catching an ocean wave. This constantly-changing wave electric field can accelerate electrons along the field line, causing some of them to hit the atmosphere. Electrons accelerated by this mechanism tend to have a broad energy spectrum, in contrast to the sharply-peaked energy spectrum typical of electrons accelerated by quasi-static electric fields. Southern Cone The Southern Cone

776-501: A velocity typically around 400 km/s, a density of around 5 ions/cm and a magnetic field intensity of around 2–5 nT (for comparison, Earth's surface field is typically 30,000–50,000 nT). During magnetic storms , in particular, flows can be several times faster; the interplanetary magnetic field (IMF) may also be much stronger. Joan Feynman deduced in the 1970s that the long-term averages of solar wind speed correlated with geomagnetic activity. Her work resulted from data collected by

873-595: 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. The altitudes where auroral emissions occur were revealed by Carl Størmer and his colleagues, who used cameras to triangulate more than 12,000 auroras. They discovered that most of

970-535: 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 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. Just as there are many types of aurora, there are many different mechanisms that accelerate auroral particles into

1067-500: Is 40, 16.8 and 3.6 million respectively. Buenos Aires is the largest metropolitan area at 13.1 million and Santiago, Chile has 6.4 million. Uruguay's capital and largest city, Montevideo , has 1.8 million, and it receives many visitors on ferry boats across the Río de la Plata from Buenos Aires, 50 km (31 mi) away. By contrast, the Patagonia region of southern Chile and Argentina

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1164-469: Is Rome, with 2.5 million inhabitants). Small towns, such as Nova Veneza , have as much as 95% of their population of Italian descent. The region also has a large German diaspora (second largest after the United States ), with People of German descent being 25% of the population of Rio Grande do Sul and 35% of the population of Santa Catarina . Mestizos make up 15.8% of the population and are

1261-637: Is common, has a policy of strong separation of church and state; it is one of the most secular countries in the Americas . Uruguay, Chile and Argentina, in that order, have the least religious residents in South America, according to their responses about the significance of religion in their lives. According to the Pew Research Center, 28% of Uruguayans, 43% of Argentines, and 41% of Chileans think of religion 'very important in their lives,' contrasting with

1358-443: 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

1455-444: 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 ). In addition, the aurora and associated currents produce a strong radio emission around 150 kHz known as auroral kilometric radiation (AKR), discovered in 1972. Ionospheric absorption makes AKR only observable from space. X-ray emissions, originating from

1552-520: 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

1649-484: 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

1746-517: Is now a critically endangered species, protected by law. The prairies region of central Argentina, Uruguay and southern Brazil is known as the Pampas . Central Chile has Mediterranean vegetation and a Mediterranean climate , grading southward into an oceanic climate . The Atacama, Patagonian and Monte deserts form a diagonal of arid lands separating the woodlands, croplands and pastures of La Plata basin from Central and Southern Chile. Apart from

1843-620: Is primarily spoken in Araucanía and adjacent areas of Patagonia , in southern Argentina and Chile. Guarani is the official language of Paraguay, the most widely spoken language in that country, and in 2010, the city of Tacuru , in the Brazilian state of Mato Grosso do Sul , adopted Guarani as the official language, besides Portuguese . It is also a co-official language in the northeastern Argentine provinces of Corrientes and Misiones . Italian (mostly its Northern dialects, such as Venetian ),

1940-407: Is regularly derived from ground data and serves as a general measure of auroral activity. Kristian Birkeland deduced that the currents flowed in the east–west directions along the auroral arc, and such currents, flowing from the dayside toward (approximately) midnight were later named "auroral electrojets" (see also Birkeland currents ). Ionosphere can contribute to the formation of auroral arcs via

2037-529: Is spoken by immigrant communities in the states of São Paulo and Paraná . By descendants in Argentina and Chile, Welsh is spoken by descendants of immigrants in the Patagonia region. Comparison of selected words Below there are selected words to show vocabulary in the dialects of the countries of the Southern Cone and other Spanish-speaking countries in South America and the dialect of Portuguese spoken in Brazil. The population of Argentina, Chile and Uruguay

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2134-547: Is spoken in rural communities across Argentina , Southern Brazil , and São Paulo where immigrants had settled. German , in various dialects, is mostly spoken in Southern Chile and Southern Brazil. As well as in the Chaco (Paraguay) by Mennonites . It is the second most spoken mother tongue in Brazil. The Southern Cone is also known to have high English proficiency compared to other South American countries. This language

2231-674: Is spoken in the Falkland Islands , a British Overseas Territory (disputed by Argentina). Polish , Dutch and Ukrainian are also spoken in Southern Brazil. Dutch is spoken in Chile as well, and Ukrainian is used in Argentina as well. Croatian and other Slavic languages are also spoken in the southernmost areas of Chilean Patagonia , reflecting patterns of immigration and settlement. Yiddish can be heard mainly in Buenos Aires , Argentina and São Paulo , Brazil. In Brazil, Japanese

2328-581: Is the subregion in Latin America with the highest Human Development Index , and it has historically had a high standard of living ; it's located at latitudes in the southern hemisphere that would correspond in the northern hemisphere to the United States , Canadian provinces, European countries (except the Nordic countries ), northern China , the Korean Peninsula and Japan . In most cases,

2425-628: Is usually not included. The climates are mostly Mediterranean temperate, but include humid subtropical, highland tropical, maritime temperate, sub-Antarctic temperate, highland cold, desert and semi-arid temperate regions. (Except for the northern regions of Argentina ( thermal equator in January), the whole country of Paraguay, the Argentina-Brazil border and the interior of the Atacama Desert ). The region rarely suffers from heat. In addition to that,

2522-447: Is very sparsely populated, with a population density of less than two people per square kilometer. The population of the Southern Cone has been strongly influenced by waves of immigration from Europe in the late nineteenth and early twentieth centuries. People of direct European descent , make up 88% of total population of Uruguay , 85% of the total population of Argentina and 65% of the total population of Chile . The remainder of

2619-522: Is why there is a color 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

2716-468: The Arctic and Antarctic ). Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky. Auroras are the result of disturbances in the Earth's magnetosphere caused by the solar wind . Major disturbances result from enhancements in the speed of the solar wind from coronal holes and coronal mass ejections . These disturbances alter

2813-476: The Explorer 33 spacecraft. 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

2910-638: The epic poem Martín Fierro . The Asado (barbecue) is a culinary tradition typical of the Southern Cone main countries and was developed by gauchos and huasos . Mate is a popular infusion throughout the Southern Cone. Like the rest of Latin America, most residents of the Southern Cone are members of the Catholic Church , with a minority of Protestants, including a significant Lutheran population in South Brazil. Other religions also present in

3007-464: The feedback instability under high ionospheric resistance conditions, observed at night time and in dark Winter hemisphere. Earth is constantly immersed in the solar wind , a flow of magnetized hot plasma (a gas of free electrons and positive ions) emitted by the Sun in all directions, a result of the two-million-degree temperature of the Sun's outermost layer, the corona . The solar wind reaches Earth with

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3104-411: The mesosphere in presence of electron precipitation . 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

3201-455: 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

3298-409: 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. These electrons often, but not always, exhibit a peak in their energy distribution, and are preferentially aligned along

3395-473: The 1970s and 1980s, each country transitioned to democratic governance, leading to a more open and participatory political environment. During the second half of 20th century, these countries were in some periods ruled by right-wing juntas , military nationalistic dictatorships. Around the 1970s, these regimes collaborated in Plan Cóndor against leftist opposition, including urban guerrillas . However, by

3492-531: The Chilean upper class, the middle classes, 66.8%-62.3% European component and 37.7%-33.2 of mixed aboriginal and lower classes at 55–52.9% European component and 47.1%-45% mix of Aboriginal. A DNA study from 2009, published in the American Journal of Human Biology , showed the genetical composition of Uruguay to be mainly European, but with Native American (which varies from 1% to 20% in different parts of

3589-508: The Roman goddess of the dawn, Aurora , who travelled from east to west announcing the coming of the Sun . Ancient Greek poets used the corresponding name " Eos " metaphorically to refer to dawn, often mentioning its play of colours across the otherwise dark sky (e.g., "rosy-fingered dawn"). The words borealis and australis are derived from the names of the ancient gods of the north wind ( Boreas ) and

3686-485: The Southern Cone as early as the second half of the 17th century, and it became a mass phenomenon between 1880 and 1920 when Italy was facing social and economic disturbances. As a consequence of mass Italian immigration, the Southern Cone has the largest Italian diaspora in the world, with people of Italian descent being the majority in many places, with the highest percentage being in Argentina (62.5% Italian ), and in

3783-483: The Southern Cone countries has been praised for being the most Libertarian and pro Free market in Latin America that gave them the profile of "emerging economies". Crime rate is significantly lower in this region compared other countries in Latin America. Since the return to democracy , Chile, Argentina, and Uruguay have experienced significant democratic stability. After enduring military dictatorships during

3880-515: 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

3977-570: The amount of acceleration imparted to the precipitating particles. Most of the planets in the Solar System , some natural satellites , brown dwarfs , and even comets also host auroras. The term aurora borealis was coined by Galileo in 1619, from the Roman Aurora, goddess of the dawn , and the Greek Boreas, god of the cold north wind . The word aurora is derived from the name of

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4074-486: 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", 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,

4171-423: 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, THEMIS probes were able to determine, for the first time, the triggering event for the onset of magnetospheric substorms . Two of

4268-456: 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

4365-447: The atmosphere. Proton auroras are usually observed at lower latitudes. Bright auroras are generally associated with Birkeland currents (Schield et al., 1969; Zmuda and Armstrong, 1973 ), 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

4462-439: 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

4559-708: The aurora borealis and changes simultaneously with changes in the northern auroral zone. The aurora australis is visible from high southern latitudes in Antarctica , the Southern Cone , South Africa , Australasia and under exceptional circumstances as far north as Uruguay . 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

4656-518: The auroral oval to active displays along the darkside and after 1–3 hours they gradually change back. Changes in auroras over time are commonly visualized using keograms . 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. 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

4753-695: 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

4850-412: The background magnetic field (comparable to the electron inertial length or ion gyroradius ), Alfvén waves develop a significant electric field parallel to the background magnetic field. This electric field can accelerate electrons to keV energies, significant to produce auroral arcs. If the electrons have a speed close to that of the wave's phase velocity, they are accelerated in a manner analogous to

4947-590: The case of Southern Brazil. The Spanish-speaking countries of the Southern Cone are divided into two main dialects: These dialects share common traits, such as a number of Lunfardo and Quechua words. Minor languages and dialects include Cordobés , Cuyo, and Portuñol , a hybrid between Rioplatense and Brazilian Portuguese that is spoken in Uruguay on the border with Brazil. Some Native American groups, especially in rural areas, continue to speak autochthonous languages , including Mapudungun (also known as Mapuche ), Quechua , Aymara , and Guarani . The first

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5044-465: The collision of particles precipitated into the atmosphere. Both incoming electrons and protons may be involved. Excitation energy is lost within the atmosphere by the emission of a photon, or by collision with another atom or molecule: 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

5141-476: The country) and also SSA (7% to 15% in different parts of the country). Similar to the rest of Latin America, the genetic ancestry of the population of the Southern Cone reflects the history of the continent: the Iberian colonizers were mostly men who arrived without women. European immigration to this part of the world in the late 19th and early 20th centuries brought more European and Middle Eastern components to

5238-468: 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 Hall current flow. By a strange twist of physics, the magnetic disturbance on the ground due to the main current almost cancels out, so most of the observed effect of auroras is due to a secondary current, the auroral electrojet . An auroral electrojet index (measured in nanotesla)

5335-608: The desert diagonal, the north–south running Andes form a major divide in the Southern Cone and constitute, for most of its part in the southern cone, the Argentina–Chile border . In the east the river systems of the La Plata basin form natural barriers and sea lanes between Argentina, Brazil, Paraguay and Uruguay. The Atacama Desert is the driest place on Earth, with some regions having no recorded rainfall in history. Besides sharing languages and colonial heritage, in this area, there

5432-416: 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 magnetosphere . These trapped particles bounce back and forth along magnetic field lines and are prevented from hitting the atmosphere by the magnetic mirror formed by the increasing magnetic field strength closer to Earth. The magnetic mirror's ability to trap

5529-404: The dune aurora phenomenon was discovered 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. 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

5626-458: 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

5723-454: 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,

5820-490: 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

5917-461: The five probes, positioned approximately one third the distance to the Moon, measured events suggesting a magnetic reconnection event 96 seconds prior to auroral intensification. 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

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6014-668: The higher values given by the residents of countries such as Peru (72%), Colombia (77%) and Ecuador (76%). The Southern Cone produced the first pope from the Western Hemisphere, Pope Francis , elected in 2013, born in Buenos Aires , Argentina . In a social survey, residents rated their countries as 'good places for gay or lesbian people to live;' the following percentages said 'yes' in Uruguay (71%), Argentina (68%), and Chile (52%). The overwhelming majority, including those of recent immigrant background, speak Spanish (in Argentina, Chile, Paraguay, and Uruguay) or Portuguese in

6111-430: The intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind. 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), producing a bow shock 12,000 km to 15,000 km (1.9 to 2.4 Re) further upstream. The width of

6208-401: The interaction of the solar wind with Earth's magnetosphere . The varying intensity of the solar wind produces effects of different magnitudes but includes one or more of the following physical scenarios. 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

6305-509: 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: Brekke (1994) also described some auroras as "curtains". 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

6402-762: 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. Protons are also associated with auroras, both discrete and diffuse. Auroras result from emissions of photons in Earth's upper atmosphere , above 80 km (50 mi), from ionized nitrogen atoms regaining an electron, and oxygen atoms and nitrogen based molecules returning from an excited state to ground state . They are ionized or excited by

6499-546: The local population. The Southern Cone is the most prosperous region in Latin America. The region has relatively high standard of living and quality of life . Chile's, Argentina's, and Uruguay's HDIs — (0.860), (0.849) and (0.830) — are the highest in Latin America, similar to European countries like Croatia , Portugal , Slovakia , Hungary or Romania . The region has a high life expectancy , and access to health care and education. In Uruguay , illiteracy technically does not exist. From an economic point of view,

6596-426: The magnetic field line. 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,

6693-432: 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

6790-422: 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. 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

6887-413: 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

6984-490: The magnetosphere is still an active area of research. 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 Alfvén waves . At small wavelengths transverse to

7081-433: The noon direction and 23° away in the midnight direction. 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

7178-498: The opposite order. Until about 1963, it was thought that these changes are due to the rotation of the Earth under a pattern fixed with respect to the Sun. Later, it was found by comparing all-sky films of auroras from different places (collected during the International Geophysical Year ) that they often undergo global changes in a process called auroral substorm . They change in a few minutes from quiet arcs all along

7275-478: The other states are more similar to the other South American countries in these issues. When the definition is not limited to entire countries, the states of the South Region and the state of São Paulo are generally included. Due to the geographical proximity, common history, geography and political cycles, Paraguay is sometimes included in what is meant by Southern Cone. But by the high Guarani influence it

7372-456: The particles associated with auroras, have also been detected. 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. In 2016, more than fifty citizen science observations described what

7469-399: The population in these countries consists predominantly of mestizos with a significant proportion of European ancestry. In São Paulo , Paraná , Rio Grande do Sul , and Santa Catarina self-identified white people are 61.3%; 70.0%; 82.3%; and 86.8% of the population respectively, with people of Italian , Polish and German ancestry predominating. Italians started to emigrate to

7566-567: The population of Brazil , and 11% of the population of Argentina . Brazil has the largest number of Arabs outside the Middle East , with 20 million Brazilians being descendants of Arabs, while the Palestinian community in Chile is considered the largest outside the Arab world . Since interethnic marriages are widespread in Latin America, complex ethnic classifications emerged, including more than

7663-589: The radiation zones and temporarily magnetically trapped particles confined by the geomagnetic field, coupled with particle acceleration processes. 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. Since then an extensive collection of measurements has been acquired painstakingly and with steadily improving resolution since

7760-431: The ribbon). The processes that cause STEVE are also associated with a picket-fence aurora, although the latter can be seen without STEVE. It is an aurora because it is caused by precipitation of electrons in the atmosphere but it appears outside the auroral oval, closer to the equator than typical auroras. When the picket-fence aurora appears with STEVE, it is below. First reported in 2020, and confirmed in 2021,

7857-416: 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

7954-454: The south wind ( Auster ) in Greco-Roman mythology . Auroras are most commonly observed in the "auroral zone", a band approximately 6° (~660 km) wide in latitude centered on 67° north and south. 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

8051-580: The southern Brazilian state of Santa Catarina (60% Italian). Among all Italians who immigrated to Brazil, 70% went to the State of São Paulo . In consequence, the State of São Paulo has more people with Italian ancestry than any region of Italy itself, with São Paulo city being the most populous city with Italian ancestry in the world, of the 10 million inhabitants of São Paulo city, 60% (6 million people) have full or partial Italian ancestry (the largest city of Italy

8148-560: The southern cone include Islam , Anglicanism , Eastern Orthodoxy , Buddhism , the Church of Jesus Christ of Latter-day Saints and Daoism . Jewish communities have thrived in cities of Argentina and Uruguay. While the Southern Cone has been conservative in some aspects of religion, it has had a tradition of social reform and liberation theology has been followed by many in the Catholic Church. Uruguay , where agnosticism and atheism

8245-883: The sport. Argentina has won the FIFA World Cup three times, while Uruguay has won the cup twice; they are the only national teams along with Brazil outside Europe to have won the cup. Argentina, Chile, Uruguay, and Brazil have all hosted the World Cup. Additionally, national teams from the region have won several Olympic medals in football. Also, football clubs from the Southern Cone countries have won large numbers of club competitions in South - American competitions, Pan-American competitions, and world-FIFA Club World Cup-level competitions. Gauchos (Argentina and Uruguay) and Huasos (Chile) are horsemen that are considered icons of national identity (like cowboys); they are featured in

8342-402: The statistics of auroral observations. Elias Loomis (1860), and later Hermann Fritz (1881) and Sophus Tromholt (1881) 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

8439-470: The term "Southern Cone" refers specifically to Chile , Argentina , and Uruguay , due to their geographical, cultural, ethnic, and economic similarities. Brazil's four southernmost states ( Paraná , Rio Grande do Sul , Santa Catarina and São Paulo ) share characteristics with Argentina, and Uruguay (high standard of living , subtropical and temperate climate , high levels of industrialization and strong European ethnic component due to immigration ),

8536-419: The tested group had at least one ancestor who was Indigenous . An autosomal DNA study from 2009 found the composition of the Argentine population to be 78.5% European, 17.3% Amerindian, and 4.2% Sub-Saharan African (SSA). Blacks made up 25% of the population of Buenos Aires in 1810, 1822 and 1838. In 1887, the government decided to cease asking Argentine citizens about their race. According to Laura López, it

8633-409: 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. A full understanding of the physical processes which lead to different types of auroras is still incomplete, but the basic cause involves

8730-402: The trajectories of charged particles in the magnetospheric plasma . These particles, mainly electrons and protons , precipitate into the upper atmosphere ( thermosphere / exosphere ). The resulting ionization and excitation of atmospheric constituents emit light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on

8827-414: 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, which can be subvisual. Auroras are occasionally seen in latitudes below the auroral zone, when

8924-406: The visible Sun at any time. 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

9021-506: The whole sky. These are also known as discrete auroras , which are at times bright enough to read a newspaper by at night. 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 . 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

9118-492: The winter presents mostly cold temperatures. Strong and constant wind and high humidity are what brings low temperatures in the winter. One of the most peculiar plants of the region is the Araucaria tree, which can be found in Chile, Argentina and parts of Brazil. The only native group of conifers found in the southern hemisphere had its origin in the Southern Cone. Araucaria angustifolia , once widespread in Southern Brazil,

9215-556: Was a way to "hide" the Black population, not only from the Census, but also from public opinion. Multiple studies concluded that Whites make 50-65% of the Chilean population and the CIA concluded that 89% are Whites, Castizos and Mestizos. The use of mitochondrial DNA and Y chromosome test results show the following: The European component is predominant (91.0%, versus 9.0% of the aboriginal one) in

9312-442: Was extensive European immigration during the 19th- and 20th-centuries, who, with their descendants, have strongly influenced the culture, social life and politics of these countries. Immigration reshaped the modern-day societies of Argentina, Chile, and Uruguay, countries where the influx of newcomers was massive. The residents of the states of the Southern Cone are avid players and fans of football , with top-notch teams competing in

9409-424: Was to them an unknown type of aurora which they named " STEVE ", for "Strong Thermal Emission Velocity Enhancement". STEVE is not an aurora but is caused by a 25 km (16 mi) wide ribbon of hot plasma at an altitude of 450 km (280 mi), with a temperature of 3,000 °C (3,270 K; 5,430 °F) and flowing at a speed of 6 km/s (3.7 mi/s) (compared to 10 m/s (33 ft/s) outside

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