Heute haben wir Sonne Konjunktion Pelion und Mond im Zwilling, da habe ich
mal Sankt-Elms-Feuer angeschaut.

Referenzen auf Englisch:
http://www.islandnet.com/~see/weather/elements/stelmo.htm
http://www.mysterylights.com/types/stelmo/

The History Of St. Elmo's Fire

The body coronal discharge is often refered to as the "corposant",
from the Spanish "corpo santos" meaning "Saint's body". St. Elmo's
fire is often taken to be a good sign, because it occurs at the end of
thunderstorms, and hence signifies clearer weather to come. Since St.
Elmo is the patron saint of sailors, the sailors took it to be a sign
of St. Elmo appearing to them, and hence the name "St. Elmo's Fire".

The Greeks termed St. Elmo's Fire "Helena", and named the rarer double
jet forms "Castor and Pollux" after the two stars in the constellation
Gemini: not suprising that the phenomenon would be named after stars
of high marine nagivational signifigance. Many famous sailors and
explorers, including Chistopher Columbus and Charles Darwin, are noted
to have observed the phenomenon.

The following quote from Shakespeare's "The Tempest" is often given as
historical evidence of the occurance of St. Elmo's Fire:-

I boarded the Kings' ship; now in the beak,
Now in the waist, the deck, in every cabin,
I flamed amazement; sometimes I'd divide
And burn in many places; on the topmast,
The yards and bowsprit, would I flame distinctly,
Then meet and join.

St. Elmo's Fire has also been mentioned in the works of Julius Caesar,
Pliny, and Melville.

The Fire Of St. Elmo

The storm watch had been set, and all hands awaited the onset of the
tempest that raged to windward. Rushing ahead of gale winds, heavy
seas rocked the brig. Then suddenly, at the mastheads and bowsprit,
ghostly blue flames leapt into the somber night, lighting the masts
like candles. The atmosphere of dread anticipation split at the sight.
The sailors to a man breathed a sigh of relief, for their patron saint
Elmo had come to watch over the brig and see her safely through the storm.

St. Elmo's Fire has long served as an omen of heavenly intervention to
sailors. The ancient Greeks termed a single jet of the fire, Helena,
and a double jet, Castor and Pollux. It has also been known by the
names St. Nicholas and St. Hermes, corpusante and Corpus Santos. The
name of St. Elmo is attributed to an Italian derivation of Sant 'Ermo
or St. Erasmus (circa 300 A.D.), the patron saint of the early
Mediterranean sailors challenging the powers of storm and sea in small
sailing vessels.

Julius Caesar wrote in his Commentaries: "In the month of February
about the second watch of the night, there suddenly arose a thick
cloud followed by a shower of hail, and the same night the points of
the spears belonging to the Fifth Legion seem to take fire."

Of all the varied names attributed to this phenomenon, St. Elmo is the
one most often passed down in English language chronicles. Mention of
St. Elmo's Fire can be found in the journals of sailors from crews of
the early explorers Columbus and Magellan, the tales of illiterate
sailors as well as those of Shakespeare and Melville, and the notes of
Charles Darwin during his voyage on H.M.S. Beagle.

A chronicler of Magellan's voyage to circle the globe,
observed:"During those storms the holy body, that is, to say St. Elmo,
appeared to us many times in light...on an exceedingly dark night on
the maintop where he stayed for about two hours or more for our
consolation."

Darwin wrote 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,
and even the very masts were pointed with a blue flame."

The appearance of St. Elmo's Fire was regarded as a good omen, for it
tended to occur in the dissipating stages of severe thunderstorms when
the most violent surface winds and seas were abating. Thus, it was
interpreted as the answer to the sailors' prayers for heavenly
intervention. Its appearance preceding a storm or during fair weather
portended that the guiding hand of St. Elmo would be present.

According to Francis Bacon quoting Pliny (Roman naturalist): "If it
be single, prognosticates a severe storm, which will
be much more severe if the ball does not adhere to the mast, but rolls
or dances about. But if there are two of then, and that, too, when the
storm has increased, it is reckoned a good sign. But if there are
three of them, the storm will become more fearful."

In Melville's Moby Dick, Ishmael observes: "All the yardarms were
tipped with a pallid fire, and touched at each tri-potential lightning
rod with three tapering white flames, each of the three tall masts was
silently burning in that sulphurous air, like gigantic wax tapers
before an altar....in all my voyagings seldom have I heard a common
oath when God's burning finger has been laid on the ship..."

With the advent of Franklin's lightning rod, church spires and metal
weather cocks, St Elmo's Fire came inland, especially in the thundery
weather of the North American continent, inspiring tales of ghosts and
spirits. With the age of flight, the Fire has appeared along the wing
tips, propellers, and antennae of aircraft, often disrupting radio
communications. There is even a theory that the Hindenburg Zeppelin
disaster may have been sparked by St. Elmo's Fire igniting leaking
hydrogen.

Physical descriptions of St. Elmo's Fire have ranged from a ghostly
dancing flame to natural fireworks. It usually is of a blue or
bluish-white colour attached to fixed, grounded conductors and has a
lifetime of minutes. The flame is heatless and non-consuming,
occasionally accompanied by a hissing sound. These latter properties
promote the myths of spiritual presence. The biblical burning bush
that was not consumed may have been displaying one form of St. Elmo's
Fire.

Despite the mythology of divine intervention that has arisen from this
natural phenomenon, St. Elmo's Fire has a scientific explanation.
Benjamin Franklin first correctly equated the Fire to atmospheric
electricity in his 1749 description of the lightning rod which he
believed could draw the electrical fire "out of the cloud silently
before it could come near enough to strike; and a light would be seen
at the point like the sailor' corpuzante" (St. Elmo' Fire).

The phenomenon is scientifically known as a corona or point discharge.
It occurs on objects, especially pointed ones, when the electrical
field potential strength reaches about one thousand volts per
centimetre. (When the electrical potential field is great enough to
overcome the resistance of medium across which it occurs, a current of
electrons will result (Ohm's Law).) During fair weather, the
electrical field strength of the atmosphere is about 1 volt per
centimetre. In the initial stages of cumulonimbus (thunderstorm)
formation, however, the field increases to 5 volts per centimetre, and
just before a lightning flash, reaches ten thousand volts per
centimetre. Thus, the atmospheric electrical field is only strong
enough, under normal circumstances, to produce St. Elmo's Fire during
thundery weather. When the storm is particularly heavily charged,
leaves, blades of grass and even the horns of cattle may glow at their
tips. In fact, the glow of St. Elmo's Fire has often been observed on
sharp objects in the vicinity of tornadoes.

When objects rise above the surface, they retain, to some degree, the
electrical potential of the ground (that is, they are grounded). For
example, a 10-meter high object, if it were a perfect conductor, would
have the same electrical potential at its top as its base. If the
atmospheric electrical field decreased at a rate of 100 volts per
meter (1 volt per centimetre), the top of the perfectly conducting
object would be at a potential 1000 volts higher than the air
surrounding it. This would cause a weak electrical current to flow
from the object to the air.

Electrical current flows away from a point of higher potential to one
of lesser potential, which is a normal, usually invisible process.
However, when the electrical potential field becomes sufficiently
strong, electrons torn from molecules of the higher potential surface
may acquire enough energy between initial escape and collision with
another molecule to avoid capture. Instead, the collision will tear
off another electron, ionizing the molecule. When the collisions
between free electrons, ionized molecules (ions), and molecules of the
air become frequent, enough energy is available to excite air
molecules into luminosity. If the region of collisions is confined to
a small volume, such as around a pointed object, the luminosity, under
low ambient light, becomes visible as a blue or bluish white glow.

Near any point conductor projecting into the atmosphere such as a
ship's mast, the lines of electrical force are deflected from their
normal position and tend to concentrate around the tip. Near this
point, the electrical field potential strength will be considerably
higher than that of the undisturbed atmosphere. The extent of this
concentration is dependent upon the geometry of the object -- the
sharper the point, the stronger the surrounding field. (It is for this
reason that lightning rods work.) Thus, ionization may occur around
sharpe points under atmospheric conditions that would not ordinarily
give ionization. When an isolated point is raised to 30 to 40 metres,
such as the mast of a large ship, coronas can occur in electrical
fields of around 200 volts per centimetre.

St. Elmo's Fire also forms on aircraft flying through heavily charged
skies, often as a precursor to a lightning strike. The glow can be
seen concentrated on wing tips, antennae, the tail, nose and propeller
blades when the potential difference is large enough. St. Elmo's Fire
can be heard "singing" on the craft's radio, a frying or hissing sound
running up and down the musical scale, according to some pilots.

Thus, in thundery weather, when the atmospheric electrical field is
tense, the mast tips may begin to glow with the Fire of St. Elmo. "
ghostly flame which danced among our sails and later stayed like
candlelights to burn brightly from the mast....When he appears, there
can be no danger"
(C. Columbus, 2nd Voyage).