Meteorological Phenomena: Saint Elmo's Fire

Like lightning, St.Elmo's Fire is a meteorological phenomenon and that's what I'll be writing about – not that cheesy movie from the 1980's. St. Elmo's fire is named after St. Erasmus of Formiae (also called St. Elmo), the patron saint of sailors. St. Elmo's Fire is simply sparking, something like a shot of electrons into the air. St. Elmo's Fire has been described as a “glow discharge” and is not the same as lightning. When it appears inside a glass tube, we know it as a neon sign. When it occurs in nature, we call it “St. Elmo's Fire. It's a continuous electric spark that people have observed everywhere.

Poput grmljavine i sijevanja, Vatra svetog Ilije (vatra svetog Nikole) ili vatra svetog Elma o kojoj ce ovdje biti rijeci je meteoroloski fenomen a ne onaj film iz 1980-tih (na koji svi pomisle kada ga spomenem…). Fenomen je naziv dobio po svetom Elmu, zastitniku moreplovaca. Vatra svetog Elma (drzati cu se ovog naziva posto je najblizi izvornom) je u biti ionizirani zrak koji odasilje sjaj. Nije rijec o vatri i nije isto sto i grmljavina. Kada se pojavi u prirodi poznat nam je pod ovim imenom no ukoliko ga promatramo unutar staklene cijevi – tada se radi o neonskom znaku (reklami itd.). Vatra svetog Elma je elektricna iskra koja traje nesto duze i ljudi su ovaj fenomen vidjali posvuda. 

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I still haven't had the opportunity to observe this phenomenon (on or off duty) but my experienced colleague that thought me basically everything I know has. He also observed another intriguing phenomenon which I will make a subject of the next installment of the meteorological phenomena column. As I've mentioned, St. Elmo's Fire has been described as a simple sparking, something like a shot of electrons into the air. It's a corona discharge, and it occurs when there is a significant imbalance in electrical charge, causing molecules to tear apart, sometimes resulting in a slight hissing sound. The first step in generating St. Elmo's Fire is a thunderstorm. There is a charge difference between the storm clouds and the ground. This difference creates voltage, or electrical pressure. In between the clouds and the ground, the atoms in the air undergo changes – electrons move farther away from protons, creating an environment that allows electrons to move around freely. In other words, the air becomes a good conductor. Once the air is conducive to the movement of electrons, those electrons continue to increase the distance between their positively charged counterpart, protons. This is ionization and plasma is simply ionized air. The phenomenon that causes St. Elmo's Fire is a dramatic difference in charge between the air and a charged object. That charged object could be a mast of a ship, the tip of an airplane wing, old chimneys or the high steeple of a church.

Ja ga jos nisam osmotrila no moj iskusni kolega i instruktor sa posla jeste a vidio je i jos jednu pojavu koja ce biti tema iduceg izdanja kolumne meteoroloskh fenomena. Kao sto sam spomenula, Vatra svetog Elma je iskra, nesto poput “pucnja” elektrona u zrak. Pojavljuje se kada je prisutan znacajan disbalans u elektricnom praznjenju, sto vodi do cijepanja molekula te ponekada rezultira blagim piskutavim zvukom. Prvi korak u nastajanju Vatre svetog Elma je sijevanje koje se desava u elektricitetom nabijenoj atmosferi. Imate razliku u praznjenju izmedju grmljavinskih oblaka i tla. Ta razlika stvara voltazu tj. elektricni pritisak. U prostoru izmedju grmljavinskih oblaka i tla, atomi zraka prolaze kroz promjene – sto je bitno u ovom slucaju – elektroni se sve vise udaljavaju od protona time stvarajuci okolinu koja dopusta elektronima da se slobodno krecu. Drugim rijecima, zrak postaje dobar provodnik. Kada se to desi, elektroni pocnu povecavati razdaljinu u odnosu na pozitivno nabijene cestice, protone. Ovo se zove ionizacija i plazma je, jednostavno receno, ioniziran zrak. Fenomen koji proizvodi Vatru svetog Elma je dramaticna razlika izmedju naboja zraka i naelektrisanog objekta. To moze biti jarbol jedrenjaka, vrh avionskog krila, stari dimnjaci ili siljak zvonika crkve. 

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The reason why St. Elmo's Fire occurs most often on pointed objects is that a tapered surface will discharge at a lower voltage level. When the air molecules tear apart, they emit light. In the case of St. Elmo's Fire, the discharge is continuous and it creates a constant glow. The glow is blue because different gasses glow different colors when they become plasmas. Earth's atmosphere has nitrogen and oxygen in it, and this particular combination happens to glow blue. One pilot described the phenomenon occurring on the windshield of a small plane while flying through a storm cloud. Whilst touching the inside of the windshield, blue streaks and miniature lightning bolts reached towards the tips of pilot's fingers. It seems like the same effect of when you touch a Tesla ball. The sensation was something like what you feel when an extremity has gone to sleep and tingles as it wakes up again. It didn't feel like a shock, but just kind of tickled. So, how does Saint Elmo's Fire appeal to you? Do you find it interesting?

Razlog iz kojeg se Vatra svetog Elma ispolji na spicastim povrsinama jeste sto ce suzeni predmeti da otpuste praznjenje nize voltaze. Kada se molekule zraka cijepaju, odasilju svjetlost. U slucaju Vatre svetog Elma, to praznjenje je kontinuirano i stvara stalan sjaj. Taj je sjaj plavicaste boje jer odredjeni gasovi svijetle drugacije kada se pretvore u plazmu. U atmosferi Zemlje se nalaze azot/ dusik i kisik te bas ta odredjena kombinacija sasvim slucajno stvara plavi sjaj. Jedan je pilot opisao dozivljaj ovog fenomena dok je upravljao avionom. Vatra svetog Elma se pojavila sa druge strane stakla malog aviona dok su letjeli kroz grmljavinski oblak. Kada je prstima njezno dotakao povrsinu stakla pojavile su se plavicaste linije i minijaturne eletricne kuglice na drugom kraju njegovih jagodica. Bukvalno isti efekat kao kada dotaknete Teslinu kuglu. Opisao je osjecaj identican onome kada vam utrne neki ekstremitet tj. one zmarce koji njime prolaze dok se “vraca iz sna”. Nije bilo kao da ga je elektricitet “pecnuo” vec je vise djelovalo kao golicanje. I kako vam se cini ovaj fenomen, da li vam je zanimljiv? 

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