St. Elmo's fire is an electrical weather phenomenon in which luminous plasma is created by a coronal discharge originating from a grounded object in an atmospheric electric field (such as those generated by thunderstorms or thunderstorms created by a volcanic explosion). The phenomenon sometimes appeared on ships at sea during thunderstorms, and was regarded by sailors with superstitious awe, accounting for the name.
Etymology
St. Elmo's fire is named after St. Erasmus of Formiae (also called St. Elmo), the patron saint of sailors. Alternatively, Peter Gonzalez is said to be the St. Elmo after whom St. Elmo's fire has its name.
Description
Physically, St. Elmo's fire is a bright blue or violet glow, appearing like fire in some circumstances, from tall, sharply pointed structures such as lightning rods, masts, spires and chimneys, and on aircraft wings.
Behavior
St. Elmo's fire can also appear on leaves, grass, and even at the tips of cattle horns. Often accompanying the glow is a distinct hissing or buzzing sound.Ball lightning is often erroneously identified as St. Elmo's fire. They are separate and distinct meteorological phenomena.
Theories
Although referred to as "fire", St. Elmo's fire is, in fact, plasma. The electric field around the object in question causes ionization of the air molecules, producing a faint glow easily visible in low-light conditions. Approximately 1,000 - 30,000 volts per centimeter is required to induce St. Elmo's fire; however, this number is greatly dependent on the geometry of the object in question. Sharp points tend to require lower voltage levels to produce the same result because electric fields are more concentrated in areas of high curvature, thus discharges are more intense at the end of pointed objects.
Saint Elmo's fire and normal sparks both can appear when high electrical voltage affects a gas. St. Elmo's fire is seen during thunderstorms when the ground below the storm is electrically charged, and there is high voltage in the air between the cloud and the ground. The voltage tears apart the air molecules and the gas begins to glow.
The nitrogen and oxygen in the earth's atmosphere causes St. Elmo's fire to fluoresce with blue or violet light; this is similar to the mechanism that causes neon lights to glow.
Art/Fiction
- One of the earliest references of St. Elmo's fire made in fiction can be found in Ludovico Ariosto's epic poem Orlando furioso (1516). It is located in the 17th canto (19th in the revised edition of 1532) after a storm has punished the ship of Marfisa, Astolfo, Aquilant, Grifon, and others, for three straight days.
- In Shakespeare's The Tempest (c. 1623), Act I, Scene II, St. Elmo's fire acquires a more negative association, appearing as evidence of the tempest inflicted by Ariel according to the command of Prospero:
- Later 18th Century and 19th Century literature associated St. Elmo's fire with bad omen or divine judgment, coinciding with the growing conventions of Romanticism and the Gothic novel. For example, in Ann Radcliffe's The Mysteries of Udolpho (1794), during a thunderstorm above the ramparts of the castle (Vol III, Ch.IV)and in Herman Melville's Moby-Dick (1851), Ch. CXIX, "The Candles", during which the ship Pequod is struck head-on by a typhoon:
- There is a reference to Saint Elmo's fire in Kurt Vonnegut's Slaughterhouse-Five. Billy Pilgrim, the protagonist, "had been seeing Saint Elmo's fire, a sort of electronic radiance around the heads of his companions and captors. It was in the treetops and on the rooftops of Luxembourg, too. It was beautiful" (Vonnegut 81).
- Saint Elmo's fire is in Castaways Of The Flying Dutchman by Brian Jacques. It is said to be green, and occurs when an avenging angel is present.
- Saint Elmo's fire is also mentioned in Gabriel Garcia Marquez's Chronicle of a Death Foretold. "The moon was high in the sky and the air was clear, and at the bottom of the precipice you could see the trickle of light from the Saint Elmo's fire in the cemetery."
- In Jonathan Safran Foer's novel Extremely Loud and Incredibly Close, the protagonist Oskar Schell discusses St. Elmo's fire while atop the Empire State Building.