On September 1st, 1859, miners following the Colorado gold rush woke up to another sunny day. Or so they thought. To their surprise, they soon discovered it was actually 1 am; and the sky wasn’t lit by the Sun, but rather by brilliant drapes of light. The blazing glow could be seen as far as the Caribbean, leading people in many regions to believe that nearby cities had caught fire. But the true cause of what would come to be known as the Carrington Event was a solar storm— the largest in recorded history.
Prvog septembra 1859. godine, rudarima zlatne groznice u Koloradu je osvanuo još jedan sunčan dan. Ili su bar tako mislili. Na njihovo iznenađenje, ubrzo su uvideli da je ipak jedan ujutru; i da nebo nije obasjano suncem, već neverovatnim svetlosnim zastorom. Ovaj blešteći sjaj mogao se videti čak i sa Kariba, što je navelo ljude u mnogim regijama da pomisle kako obližnji gradovi gore. Međutim, pravi uzrok onoga što će postati poznato pod imenom Karingtonov događaj je bila solarna oluja— najveća zabeležena u istoriji.
Solar storms are one of many astrophysical phenomena caused by magnetic fields. These fields are generated by movements of electrically charged particles like protons and electrons. For example, Earth’s magnetic field is generated by charged molten metals circulating in the planet's outer core. Similarly, the Sun’s magnetic field is generated by large convective movements in the plasma that composes the star. As this plasma slowly swirls, it creates areas of intense magnetic activity called sunspots. The magnetic fields that form near these regions often become twisted and strained. And when they’re stretched too far, they snap into simpler configurations, releasing energy that launches plasma from the Sun’s surface. These explosions are known as coronal mass ejections.
Solarne oluje su jedan od astrofizičkih fenomena uzrokovanih magentnim poljima. Ova polja nastaju kretanjem naelektrisanih čestica kao što su protoni i elektroni. Na primer, Zemljino magnetno polje nastaje od naelektrisanih topljenih metala koji kruže u spoljašnjem jezgru planete. Slično tome, Sunčevo magnetno polje nastaje velikim konvektivnim pokretima u plazmi koja sačinjava ovu zvezdu. Kako se ova plazma polako kovitla, ona stvara oblasti jake magnetne aktivnosti koje se zovu Sunčeve pege. Magnetna polja koja se formiraju u blizini ovih oblasti često postaju uvrnuta i napregnuta. A kada se previše razvuku, ona pucaju u jednostavnije konfiguracije, oslobađajući energiju koja ispušta plazmu sa Sunčeve površine. Ove eksplozije su poznate kao koronalne eksplozije.
The plasma— mostly made of protons and electrons— accelerates rapidly, quickly reaching thousands of kilometers per second. A typical coronal mass ejection covers the distance between the Sun and the Earth in just a couple of days, flowing along the magnetic field that permeates the solar system. And those that cross the Earth’s path are drawn to its magnetic field lines, falling into the atmosphere around the planet’s magnetic poles. This tidal wave of high-energy particles excites atmospheric atoms such as oxygen and nitrogen, causing them to rapidly shed photons at various energy levels. The result is a magnificent light show we know as the auroras. And while this phenomenon is usually only visible near the Earth’s poles, strong solar storms can bring in enough high energy particles to light up large stretches of the sky.
Plazma— većinom sačinjena od protona i elektrona— se naglo ubrzava, brzo dostižući hiljade kilometara po sekundi. Tipična koronalna eksplozija pokriva razdaljinu između Sunca i Zemlje za samo nekoliko dana, tako što teče duž magnetnog polja koje prožima Sunčev sistem. A one koje prelaze Zemljinu putanju su privučene linijama njenog magnetnog polja, te upadaju u atmosferu oko njenih magnetnih polova. Ovaj plimni talas čestica visoke energije pobuđuje atmosferske atome poput kiseonika i azota, uzrokujući da brzo odbacuju fotone na različitim nivoima energije. Rezultat je veličanstveni svetlosni šou nama poznat kao aurora. I dok je ovaj fenomen uglavnom jedino vidljiv u blizini polova, jake solarne oluje mogu doneti dovoljno čestica visoke energije da osvetle velike površine neba.
The magnetic fields in our solar system are nothing compared to those found in deep space. Some neutron stars generate fields 100 billion times stronger than those found in sunspots. And the magnetic fields around supermassive black holes expel jets of gas that extend for thousands of light years. However, on Earth, even weak solar storms can be surprisingly dangerous. While the storms that reach us are generally harmless to humans, the high-energy particles falling into the atmosphere create secondary magnetic fields, which in turn generate rogue currents that short-circuit electrical equipment. During the Carrington Event, the only widespread electrical technology was the telegraph. But since then, we've only become more dependent on electrical systems. In 1921, another powerful solar storm caused telephones and telegraph equipment around the globe to combust. In New York, the entire railway system was shut down and fires broke out in the central control building. Comparatively weak storms in 1989 and 2003 turned off regions of the Canadian power grid and damaged multiple satellites. If we were hit by a storm as strong as the Carrington Event today, it could devastate our interconnected, electrified planet.
Magnetna polja u našem Sunčevom sistemu su ništa naspram onih u dubokom svemiru. Neke neutronske zvezde stvaraju polja 100 milijardi puta jača od onih u Sunčevim pegama. A magnetna polja oko supermasivnih crnih rupa izbacuju mlazove gasa koji se prostire hiljadama svetlosnih godina. Međutim, na Zemlji, i slabe solarne oluje mogu biti iznenađujuće opasne. Dok su oluje koje dospevaju do nas uglavnom bezopasne za ljude, čestice visoke energije koje padaju u atmosferu stvaraju sekundarna magnetna polja, koja onda stvaraju odbegle struje koje dovode do kratkog spoja električne opreme. Tokom Karingtonovog događaja, jedina široko rasprostranjena električna tehnologija bio je telegraf. Ali od tada, postali smo sve više zavisni od električnih sistema. Godine 1921, još jedna jaka solarna oluja izazvala je da telefoni i telegrafska oprema širom sveta eksplodiraju. U Njujorku, čitav železnički sistem je bio obustavljen i izbili su požari u središnjoj kontrolnoj zgradi. Relativno slabe oluje 1989. i 2003. godine gase delove kanadske električne mreže i nanose štetu na više satelita. Kada bi nas danas pogodila oluja jaka koliko i Karingtonov događaj, mogla bi uništiti našu međusobno povezanu, naelektrisanu planetu.
Fortunately, we're not defenseless. After centuries of observing sunspots, researchers have learned the Sun’s usual magnetic activity follows an 11-year cycle, giving us a window into when solar storms are most likely to occur. And as our ability to forecast space weather has improved, so have our mitigation measures. Power grids can be shut off in advance of a solar storm, while capacitors can be installed to absorb the sudden influx of energy. Many modern satellites and spacecraft are equipped with special shielding to absorb the impact of a solar storm. But even with these safeguards, it’s hard to say how our technology will fare during the next major event. It’s possible we’ll be left with only the aurora overhead to light the path forward.
Srećom, nismo bespomoćni. Nakon vekova posmatranja Sunčevih pega, istraživači su uvideli da Sunčeva tipična magnetna aktivnost prati ciklus od 11 godina, što nam daje uvid u to kada solarne oluje imaju najveće šanse da se pojave. I kako se naša sposobnost prognoze svemirskog vremena poboljšavala, isto se desilo i sa merama ublažavanja. Električne mreže se mogu isključiti pre solarne oluje, dok se kondenzatori mogu ugraditi tako da apsorbuju nagli priliv energije. Mnogi savremeni sateliti i letelice opremljeni su posebnom zaštitom koja apsorbuje uticaj solarne oluje. Ali čak i sa ovim merama zaštite, teško je reći kako će naša tehnologija podneti sledeći veliki događaj. Moguće je da će nam jedino preostati polarna svetlost iznad nas da nam obasja put napred.