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For the 1985 Brat Pack movie, see St. Elmo's Fire (film); for the 1975 song by Brian Eno, see St. Elmo's Fire (song); for the 1985 single by John Parr, see St. Elmo's Fire (Man in Motion). St. Elmo's fire is an electro-luminescent corona discharge caused by the ionization of the air during thunderstorms inside of a strong electric field. Although referred to as "fire", St. Elmo's fire is in fact a low density, relatively low temperature plasma caused by massive atmospheric electrical potential differences which exceed the dielectric breakdown value of air at around 3 megavolts per meter. St. Elmo's fire is named after Erasmus of Formiae (also called St. Elmo), the patron saint of sailors (who sometimes held its appearance to be auspicious). Alternately, Peter Gonzalez is said to be the St. Elmo after whom St. Elmo's fire has its name.
Observation Physically, St. Elmo's fire is a bright blue-white glow, appearing like fire in some circumstances, often in double or triple jets, from tall, sharply pointed structures such as masts, spires and chimneys, and on aircraft wings. It is named such because the phenomenon commonly occurs at the mastheads of ships during thunderstorms at sea, and St. Elmo is the patron saint of sailors. Benjamin Franklin correctly observed in 1749 that it is electric in nature. It is said that St. Elmo's fire can also appear from the tips of cattle horns during a thunderstorm, or sharp objects in the middle of a tornado, but is not the same phenomenon as ball lightning, although they are possibly related. In ancient Greece, the appearance of a single one was called Helena and two were called Castor and Polydeuces. Other works discharge (st elmos fire) on aircraft window.jpg|thumb|right|300px|Image of a Lichtenberg figure like static discharge occurring on the outer surface of a glass cockpit window during flight through a strong thunderstorm. This phenomenon is commonly referred to as St. Elmo's fire by pilots, though strictly speaking, it is simply a form of static discharge. The phenomenon of St. Elmo's fire proper, that is, a diffuse corona discharge, also can very briefly be seen in the video from which this image was taken (at time 2:00 minutes). Full video:http://www.youtube.com/watch?v=4sA-Hk_jnPg&eurl=. References to St. Elmo's fire, often known as "corposants" or "corpusants" from the Latin Corpus Sancti (Holy Bodies), can be found in the works of Julius Caesar (De Bello Africo,47), Pliny the Elder (Naturalis Historia, book 2, par. 101) , Herman Melville, and Antonio Pigafetta's journal of his voyage with Ferdinand Magellan. "Look aloft!!' cried Starbuck. 'The corpusants! The corpusants!' All the yard-arms were tipped with a pallid fire; and touched at each tri-pointed lightning-rod-end with three tapering white flames, each of the three tall masts were silently burning in the sulphurous air, like three gigantic wax tapers before an altar." – Herman Melville, Moby Dick. In the 1956 film Moby Dick, the fire is shown burning the masts and rigging of the Pequod during a fierce storm. Captain Ahab (played by Gregory Peck) holds a spear aloft in front of the scared crew and the fire appears around its tip and shaft. He then extinguishes the fire by slowly running his hand down the spear and declaring "Thus I put out the last fear!". Charles Darwin noted the effect while aboard the Beagle and wrote of the episode in a letter to J.S. Henslow that one night when the Beagle was anchored in the estuary of the Rio Plata: "Everything was in flames, the sky with lightning, the water with luminous particles There is a possible reference to St. Elmo's fire in Samuel Taylor Coleridge's The Rime of the Ancient Mariner: About, about, in reel and rout The death-fires danced at night; The water, like a witch's oils, Burnt green, and blue, and white. A representation of St. Elmo's fire on cows' horns is seen near the end of Part 1 of the television adaptation of the Pulitzer Prize-winning novel Lonesome Dove by Larry McMurtry. Trivia See also | ||||||||
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