Northern Lights — Fiery Dance in Heaven

The north­ern lights are a mys­ti­cal, unpre­dictable and beau­ti­ful phe­nom­e­non that sud­den­ly appears and just as sud­den­ly dis­ap­pears. In this arti­cle, in addi­tion to breath­tak­ing pho­tographs, you will learn about what kind of phe­nom­e­non this is, get acquaint­ed with a num­ber of inter­est­ing facts that you prob­a­bly didn’t even know about. We will even delve into the ancient his­to­ry and folk­lore of var­i­ous peo­ples to learn more about the ori­gin of the north­ern lights. If the the­o­ry is too com­pli­cat­ed for you, leave your ques­tions in the com­ments, and be sure to get a detailed answer. I look for­ward to your feed­back, addi­tions and com­ments.

In past issues of Life­Globe, we have writ­ten about such won­der­ful nat­ur­al phe­nom­e­na as rain­bows, as well as unusu­al clouds. Today I will tell you about the North­ern Lights. This is the glow of the upper lay­ers of the plan­et’s atmos­phere, which have a mag­ne­tos­phere, due to their inter­ac­tion with charged par­ti­cles of the solar wind.

The North­ern Lights are an amaz­ing­ly beau­ti­ful, breath­tak­ing sight. It can last from sev­er­al hours to sev­er­al days.

The answer to the ques­tion, what is it, was the first to find Mikhail Lomonosov. After con­duct­ing count­less exper­i­ments, he sug­gest­ed the elec­tri­cal nature of this phe­nom­e­non. Sci­en­tists who con­tin­ued to study this phe­nom­e­non, on the basis of exper­i­ments, con­firmed the cor­rect­ness of his hypoth­e­sis. They filled hol­low tubes with nitro­gen, neon, hydro­gen, argon and oth­er rar­efied gas­es, pass­ing an elec­tric cur­rent through them. Each gas glowed (lumi­nesced) dif­fer­ent­ly. Then it was found that the glow of rar­efied gas­es occurs in the upper part of the atmos­phere — the ionos­phere (at an alti­tude of 80 to 1,000 km). A close con­nec­tion with the activ­i­ty of the Sun was also revealed. When explo­sions occur on it, charged par­ti­cles (cor­pus­cles) rush into the Earth­’s ionos­phere. Col­lid­ing with par­ti­cles of rar­efied gas­es locat­ed in the ionos­phere, they make them glow: the more active the Sun, the more the north­ern lights cov­er a larg­er area of ​​the sky. This phe­nom­e­non is espe­cial­ly strong dur­ing the max­i­mum peri­od of the 11-year cycle of solar activ­i­ty.

So, the north­ern lights arise as a result of the bom­bard­ment of the upper atmos­phere by charged par­ti­cles mov­ing towards the Earth along the geo­mag­net­ic field lines from a region of near-Earth out­er space called the plas­ma lay­er. The pro­jec­tion of the plas­ma sheet along the geo­mag­net­ic field lines onto the Earth­’s atmos­phere has the form of rings sur­round­ing the north and south mag­net­ic poles (auro­ral ovals). Space physics is engaged in reveal­ing the rea­sons lead­ing to pre­cip­i­ta­tion of charged par­ti­cles from the plas­ma lay­er. It has been exper­i­men­tal­ly estab­lished that the ori­en­ta­tion of the inter­plan­e­tary mag­net­ic field and the pres­sure of the solar wind plas­ma play a key role in stim­u­lat­ing pre­cip­i­ta­tion. In a very lim­it­ed area of ​​the upper atmos­phere, auro­ras can be caused by low-ener­gy charged par­ti­cles of the solar wind enter­ing the polar ionos­phere through the north and south polar cusps. In the north­ern hemi­sphere, cusp auro­ra can be observed over Sval­bard around noon. When ener­getic par­ti­cles of the plas­ma lay­er col­lide with the upper atmos­phere, the atoms and mol­e­cules of the gas­es includ­ed in its com­po­si­tion are excit­ed. The radi­a­tion of excit­ed atoms is in the vis­i­ble range and is observed as auro­ra. The spec­tra of auro­ras depend on the com­po­si­tion of the atmos­pheres of the plan­ets: for exam­ple, if for the Earth the emis­sion lines of excit­ed oxy­gen and nitro­gen in the vis­i­ble range are the bright­est, then for Jupiter, the emis­sion lines of hydro­gen in the ultra­vi­o­let. Since ion­iza­tion by charged par­ti­cles occurs most effi­cient­ly at the end of the par­ti­cle path and the den­si­ty of the atmos­phere decreas­es with height in accor­dance with the baro­met­ric for­mu­la, the height of the appear­ance of auro­ras depends quite strong­ly on the para­me­ters of the planet’s atmos­phere, for exam­ple, for the Earth with its rather com­plex com­po­si­tion of the atmos­phere, a red glow of oxy­gen is observed at alti­tudes of 200–400 km, and the com­bined glow of nitro­gen and oxy­gen at an alti­tude of ~110 km. In addi­tion, these fac­tors also deter­mine the shape of the auro­ras — a dif­fuse upper and rather sharp low­er bound­aries.

The north­ern lights are observed main­ly at high lat­i­tudes of both hemi­spheres in oval zones-belts sur­round­ing the Earth­’s mag­net­ic poles — auro­ral ovals. The diam­e­ter of the auro­ral ovals is ~3000 km dur­ing the qui­et Sun, on the day side the zone bound­ary is 10–16° from the mag­net­ic pole, and on the night side it is 20–23°. Since the Earth­’s mag­net­ic poles are ~12° apart from the geo­graph­ic poles, auro­ras are observed at lat­i­tudes of 67–70°; how­ev­er, dur­ing solar activ­i­ty, the auro­ral oval expands and auro­ras can be observed at low­er lat­i­tudes, 20–25° south or north of their bound­aries. nor­mal man­i­fes­ta­tion. The north­ern lights in spring and autumn appear much more often than in win­ter and sum­mer. The peak fre­quen­cy falls on the peri­ods clos­est to the spring and autumn equinox­es. Dur­ing the auro­ra, a huge amount of ener­gy is released in a short time (dur­ing one of the dis­tur­bances record­ed in 2007 — 1?2 joules, about the same as dur­ing an earth­quake of mag­ni­tude 5.5. When observed from the Earth­’s sur­face, the auro­ra appears in the form a gen­er­al rapid­ly chang­ing glow of the sky or mov­ing beams, bands, crowns, “cur­tains.” The dura­tion of auro­ras ranges from tens of min­utes to sev­er­al days.

The mag­net­ic fields of the giant plan­ets of the solar sys­tem are much stronger than the Earth­’s mag­net­ic field, which caus­es a larg­er scale of the auro­ras of these plan­ets com­pared to the auro­ras of the Earth. A fea­ture of obser­va­tions from the Earth (and in gen­er­al from the inner regions of the solar sys­tem) of the giant plan­ets is that they face the observ­er with the side illu­mi­nat­ed by the Sun and in the vis­i­ble range their auro­ras are lost in the reflect­ed sun­light. How­ev­er, due to the high con­tent of hydro­gen in their atmos­pheres, the radi­a­tion of ion­ized hydro­gen in the ultra­vi­o­let range and the low albe­do of the giant plan­ets in the ultra­vi­o­let, with the help of extra-atmos­pher­ic tele­scopes (the Hub­ble space tele­scope), fair­ly clear images of the auro­ras of these plan­ets were obtained. A fea­ture of Jupiter is the influ­ence of its satel­lites on the auro­ras: in the areas of “pro­jec­tions” of beams of mag­net­ic field lines on the auro­ral oval of Jupiter, bright areas of the auro­ra are observed, excit­ed by cur­rents caused by the motion of satel­lites in its mag­ne­tos­phere and the ejec­tion of ion­ized mate­r­i­al by satel­lites — the lat­ter is espe­cial­ly pro­nounced in the case of Io with its vol­can­ism. On the image of the auro­ra of Jupiter, made by the Hub­ble space tele­scope, the fol­low­ing pro­jec­tions are notice­able: Io (spot with a “tail” along the left limb), Ganymede (in the cen­ter) and Europa (slight­ly below and to the right of the Ganymede foot­print).

How­ev­er, sci­en­tif­ic def­i­n­i­tions seem too dry and soul­less when col­ored rays and stripes run across the sky, or a mul­ti-col­ored pul­sat­ing cur­tain flash­es across the whole space from east to west.

In ancient times, peo­ple did not under­stand nature, so many myths and beliefs are asso­ci­at­ed with the North­ern Lights.

In ancient Norse mythol­o­gy, the Bifrost Bridge is often men­tioned — a burn­ing, trem­bling arch that cross­es the sky, along which the gods could descend from heav­en to earth. It is pos­si­ble that the auro­ra bore­alis was the pro­to­type for this bridge. In some leg­ends, the rays of the auro­ra bore­alis are per­ceived as fires car­ried by Valkyries (daugh­ters of a glo­ri­ous war­rior or king who soar on a winged horse over the bat­tle­field and select the most brave war­riors to take them after their death to the heav­en­ly cham­ber of Val­hal­la). War­rior maid­ens are depict­ed wear­ing hel­mets, with shields and spears; from the bril­liance of their armor, accord­ing to leg­end, the north­ern lights appear in the sky.

In addi­tion to the Bifrost bridge, Finnish mythol­o­gy refers to the riv­er — Ruja — which burns with fire, and marks the bor­der between the realms of the liv­ing and the dead.

In Nor­we­gian folk­lore, the north­ern lights were described as a har­bin­ger of bad weath­er: it was assumed that the bright flash­es were fol­lowed by snow and wind. Oth­er Nor­we­gian folk leg­ends say that the north­ern lights are a heav­en­ly dance of the souls of dead maid­ens.

The Eski­mos in the Hud­son Bay area of ​​North Amer­i­ca, as well as else­where, know a great deal about the phe­nom­e­non of the north­ern lights. There is a myth among the Eski­mos that the auro­ra can be caused by whistling, while clap­ping your hands will make it go out. Oth­er Eski­mo myths say that the auro­ra is caused by spir­its play­ing sky foot­ball with a wal­rus skull.

Some Inu­it groups regard the north­ern lights as an indi­ca­tor of good weath­er to be brought by the spir­its. The Eski­mos at Poit Bar­row in Alas­ka saw the north­ern lights as malev­o­lent, and car­ried weapons with them for pro­tec­tion if they need­ed to go out­side dur­ing the north­ern lights. Also, some Eski­mos say: “He who looks at the north­ern lights for a long time will soon go crazy!”

Some tribes of North Amer­i­can Indi­ans believe that the north­ern lights are the light of lanterns car­ried by spir­its search­ing for the souls of dead hunters. Like the Eski­mos of Poit Bar­row, the Fox Indi­ans of Wis­con­sin feared the auro­ra, see­ing it as the ghosts of their dead ene­mies. Oth­er tribes expe­ri­enced the north­ern lights as the light of the lights used by the all-pow­er­ful north­ern shamans.

The North­ern Lights also entered the folk­lore of the Aus­tralian Abo­rig­ines, who saw them as the dance of the gods across the sky. The North­ern Lights were very pos­si­bly the source of Chi­nese drag­on leg­ends. The ser­pen­tine forms of auro­ral active zones are often depict­ed as celes­tial ser­pents in ancient chron­i­cles. Euro­pean drag­on leg­ends, too, may have their ori­gin in auro­ra activ­i­ty. How iron­ic that nowa­days many his­to­ri­ans believe that the leg­endary bat­tle of the patron saint of the Eng­lish (St. George) was most like­ly with this fre­quent Scot­tish phe­nom­e­non, the auro­ra, and not with the drag­on!

In the recent past, mis­con­cep­tions about the cause of the auro­ra were still com­mon among the gen­er­al pub­lic. For exam­ple, many peo­ple in the Amer­i­can Mid­west believed that the auro­ra was the reflec­tion of sun­light off the polar ice, over­look­ing the end­less dark­ness of the win­ter months in the Arc­tic! Anoth­er roman­tic expla­na­tion was that the light of the auro­ra is the result of ice­berg col­li­sions in the polar seas.

The most impres­sive North­ern Lights appear with a cycle of 11 years and 22 years, depend­ing on solar activ­i­ty. Satel­lite imagery con­firmed the old the­o­ry that the auro­ras in the north­ern and south­ern hemi­spheres are almost mir­ror images of each oth­er — these are rings with a diam­e­ter of about 4 thou­sand km around each pole. In the Mid­dle Ages, when the north mag­net­ic pole was locat­ed to the east, the auro­ra was often vis­i­ble in Scan­di­navia, north­ern Rus­sia and north­ern Chi­na. The chron­i­clers of that time explained this by the fact that it was giants fight­ing in the sky, or that spears sparkling with mul­ti-col­ored lights were fly­ing from heav­en to earth. Now the north­ern lights can often be observed in Scot­land, espe­cial­ly in April; it appears about four times a year in north­ern Flori­da, but it is most clear­ly vis­i­ble near the mag­net­ic poles: for exam­ple, in north­ern Cana­da and in the Ross Trench in Antarc­ti­ca. One of the most con­ve­nient places is North­ern Scan­di­navia; It is good to observe the auro­ra on the island of Sval­bard, north of Nor­way. And the auro­ra bore­alis is best observed on the Antarc­tic con­ti­nent. The auro­ras are also observed from space, where, among oth­er things, there is no dis­tort­ing influ­ence of the low­er dense lay­ers of the atmos­phere. Obser­va­tions from manned space­craft and orbital sta­tions have pro­vid­ed rich mate­r­i­al on the spa­tial arrange­ment of auro­ras, their change in time, and many fea­tures of this phe­nom­e­non. More­over, space­craft have made it pos­si­ble to take mea­sure­ments inside the auro­ra. Auro­ras can also be observed on the day side of the Earth in this way.

It is safe to say that research in recent decades, includ­ing the study of the phe­nom­e­non from arti­fi­cial Earth satel­lites and rock­ets and the cre­ation of arti­fi­cial auro­ras, has sig­nif­i­cant­ly enriched our knowl­edge of the north­ern lights. It is clear that not only the rid­dle of the north­ern lights has been unrav­eled, but also a large amount of fac­tu­al mate­r­i­al has been accu­mu­lat­ed about the space sur­round­ing our plan­et, the state of the inter­plan­e­tary medi­um and solar radi­a­tion, includ­ing flux­es of charged par­ti­cles. And yet the prob­lem of the north­ern lights is still far from being solved. Indeed, we know that this is a glow of the upper atmos­phere at high lat­i­tudes of the north­ern and south­ern hemi­spheres of the Earth, caused by ener­getic charged par­ti­cles invad­ing the Earth­’s mag­ne­tos­phere on their way from the Sun. The main reg­u­lar­i­ties of the man­i­fes­ta­tion of the north­ern lights are also known: their depen­dence on height, geo­graph­i­cal loca­tion, solar activ­i­ty, per­tur­ba­tions of the Earth­’s mag­net­ic field, etc. And yet, at the present time, we still can­not not only describe quan­ti­ta­tive­ly this phe­nom­e­non, but even pre­dict in advance many of the reg­u­lar­i­ties of the forth­com­ing north­ern lights. The prob­lem of north­ern lights is too com­plex and mul­ti­fac­eted. For exam­ple, the con­nec­tion between the north­ern lights and the weath­er is still unclear. North­ern­ers are well aware that the north­ern lights are more often observed on frosty nights. There is no expla­na­tion for this yet. At the same time, unex­pect­ed rela­tion­ships are emerg­ing, wait­ing for their future researchers, in rather unusu­al ques­tions. Is it only the fear of incom­pre­hen­si­ble impres­sive nat­ur­al phe­nom­e­na that under­lies these super­sti­tions? It is now well known that solar rhythms with dif­fer­ent peri­ods (27 days, 11 years, etc.) affect the most diverse aspects of life on Earth. Solar and mag­net­ic storms (and the asso­ci­at­ed north­ern lights) can cause an increase in var­i­ous dis­eases, includ­ing dis­eases of the human car­dio­vas­cu­lar sys­tem. Changes in the cli­mate on Earth, the occur­rence of droughts and floods, earth­quakes, etc. are asso­ci­at­ed with solar cycles. All this makes us once again seri­ous­ly think about the con­nec­tion between the north­ern lights and earth­ly cat­a­clysms and trou­bles. Maybe the old ideas about such a con­nec­tion are not so stu­pid? The north­ern lights sig­nal the place and time of the impact of the Cos­mos on earth process­es. The inva­sion of charged par­ti­cles that caus­es them affects many aspects of our lives. The ozone con­tent and the elec­tric poten­tial of the ionos­phere change, the heat­ing of the ionos­pher­ic plas­ma excites waves in the atmos­phere. All this affects the weath­er. Due to addi­tion­al ion­iza­tion in the ionos­phere, sig­nif­i­cant elec­tric cur­rents begin to flow, the mag­net­ic fields of which dis­tort the Earth­’s mag­net­ic field, which direct­ly affects the health of many peo­ple. Thus, through the north­ern lights and the process­es asso­ci­at­ed with them, the Cos­mos affects the nature around us and its inhab­i­tants.