„Foo-fighters“ is a phrase coined to designate anomalous and unidentified luminous phenomena having been sighted by pilots during World War II.
They were often perceived as orange, red or yellow fireballs maneuvering about aircrafts.
(It is worth noting, however, that there is a huge diversity of sightings related to that time period. See here).
Ever since the 1940s, it has been claimed now and then (for a recent example, see here) that a phenomenon called „St. Elmo’s fire“ (SEF) would be a good generic explanation of most (albeit not all) cases.
I decided to critically examine this possibility in light of the underscored sentence above describing as typical a foo-fighter can be.
I read different articles on St. Elmo’s fire in German, English, Italian, Spanish and Dutch. and think I have acquired a fairly good understanding of its features even though I obviously lack a thorough knowledge of the underlying physical equations.
I’ll start our examination by quoting the English Wikipedia which is (in this non-controversial case) not too bad.
St. Elmo’s fire
St. Elmo’s fire (also St. Elmo’s light) is a weather phenomenon in which luminous plasma is created by a coronal discharge from a sharp or pointed object in a strong electric field in the atmosphere (such as those generated by thunderstorms or created by a volcanic eruption).
St. Elmo’s fire is named after St. Erasmus of Formia (also called St. Elmo, one of the two Italian names for St. Erasmus, the other being St. Erasmo), the patron saint of sailors. The phenomenon sometimes appeared on ships at sea during thunderstorms and was regarded by sailors with religious awe for its glowing ball of light, accounting for the name. Because it is a sign of electricity in the air, which can interfere with compass readings, some sailors may have regarded it as an omen of bad luck and stormy weather. Other references indicate that sailors may have actually considered St. Elmo’s fire as a good omen (as in, a sign of the presence of their patron saint).
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 or nosecones. 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. It is sometimes confused with ball lightning.
St. Elmo’s fire is a form of matter called plasma, which is also produced in stars, high temperature flame, and by lightning. The electric field around the object in question causes ionization of the air molecules, producing a faint glow easily visible in low-light conditions. Roughly 1000 volts per centimeter induces St. Elmo’s fire; the number depends greatly on the geometry of the object. Sharp points lower the required voltage because electric fields are more concentrated in areas of high curvature, so discharges are more intense at the ends of pointed objects.
Conditions that can generate St.Elmo’s fire are present during thunderstorms, when high voltage differentials are present between clouds and the ground underneath. Air molecules glow owing to the effects of such voltage, producing St. Elmo’s fire.
In ancient Greece, the appearance of a single one was called helene (Greek: ἑλένη), meaning torch, and two were called Castor and Pollux. Occasionally, it was associated with the Greek element of fire, as well as with one of Paracelsus’s elementals, specifically the salamander, or, alternatively, with a similar creature referred to as an acthnici.
References to St. Elmo’s fire can be found in the works of Julius Caesar (De Bello Africo, 47), Pliny the Elder (Naturalis Historia, book 2, par. 101), and Antonio Pigafetta’s journal of his voyage with Ferdinand Magellan. St. Elmo’s fire, also known as „corposants“ or „corpusants“ from the Portuguese corpo santo („holy body“), was a phenomenon described in The Lusiads.
In 15th-century Ming China, Admiral Zheng He and his associates composed the Liujiagang and Changle inscriptions, the two epitaphs of the treasure voyages where they made a reference to St. Elmo’s fire as a divine omen of Tianfei, the goddess of sailors and seafarers.
The power of the goddess, having indeed been manifested in previous times, has been abundantly revealed in the present generation. In the midst of the rushing waters it happened that, when there was a hurricane, suddenly a divine lantern was seen shining at the masthead, and as soon as that miraculous light appeared the danger was appeased, so that even in the peril of capsizing one felt reassured and that there was no cause for fear.
— Admiral Zheng He and his associates (Changle inscription) 
Robert Burton wrote of St. Elmo’s fire in his Anatomy of Melancholy: „Radzivilius, the Lithunian duke, calls this apparition, Sancti Germani sidus; and saith moreover that he saw the same after in a storm, as he was sailing, 1582, from Alexandria to Rhodes“. This refers to the voyage made by Mikołaj Krzysztof „the Orphan“ Radziwiłł in 1582–1584.
On the 9th of May, 1605, while on the second voyage of John Davis commanded by Sir Edward Michelborne to the East Indies, an unknown writer aboard the Tigre describes the phenomenon; „In the extremity of our storm appeared to us in the night, upon our maine Top-mast head, a flame about the bigness of a great Candle, which the Portugals call Corpo Sancto, holding it a most divine token that when it appeareth the worst is past. As, thanked be God, we had better weather after it“.
On Thursday February 20, 1817,[note 1] during a severe electrical storm James Braid, then surgeon at Lord Hopetoun’s mines at Leadhills, Lanarkshire, had an extraordinary experience whilst on horseback:
On Thursday 20th, I was gratified for a few minutes with the luminous appearance described above [viz., „such flashes of lightning from the west, repeated every two or three minutes, sometimes at shorter intervals, as appeared to illumine the whole heavens“]. It was about nine o’clock, P.M. I had no sooner got on horseback than I observed the tips of both the horse’s ears to be quite luminous: the edges of my hat had the same appearance. I was soon deprived of these luminaries by a shower of moist snow which immediately began to fall. The horse’s ears soon became wet and lost their luminous appearance; but the edges of my hat, being longer of getting wet, continued to give the luminous appearance somewhat longer.
I could observe an immense number of minute sparks darting towards the horse’s ears and the margin of my hat, which produced a very beautiful appearance, and I was sorry to be so soon deprived of it.
The atmosphere in this neighbourhood appeared to be very highly electrified for eight or ten days about this time. Thunder was heard occasionally from 15th to 23d, during which time the weather was very unsteady: frequent showers of hail, snow, rain, &c.
I can find no person in this quarter who remembers to have ever seen the luminous appearance mentioned above, before this season,—or such a quantity of lightning darting across the heavens,—nor who have heard so much thunder at that season of the year.
This country being all stocked with sheep, and the herds having frequent occasion to pay attention to the state of the weather, it is not to be thought that such an appearance can have been at all frequent, and none of them to have observed it.[note 2]
— James Braid, 1817
Weeks earlier, reportedly on January 17, 1817, a luminous snowstorm occurred in Vermont and New Hampshire. Saint Elmo’s fire appeared as static discharges on roof peaks, fence posts, and the hats and fingers of people. Thunderstorms prevailed over central New England.
Everything is in flames, — the sky with lightning, — the water with luminous particles, and even the very masts are pointed with a blue flame.
— Charles Darwin, 1832
St. Elmo’s fire is reported to have been seen during the Siege of Constantinople by the Ottoman Empire in 1453. It reportedly was seen emitting from the top of the Hippodrome. The Byzantines attributed it to a sign that the Christian God would soon come and destroy the conquering Muslim army. According to George Sphrantzes, it disappeared just days before Constantinople fell, ending the Byzantine Empire.
In Two Years Before the Mast, Richard Henry Dana, Jr. describes seeing a corposant in the Horse latitudes of the northern Atlantic Ocean. However, he may have been talking about ball lightning; as mentioned earlier it is often erroneously identified as St. Elmo’s fire: „There, directly over where we had been standing, upon the main top-gallant mast-head, was a ball of light, which the sailors name a corposant (corpus sancti), and which the mate had called out to us to look at. They were all watching it carefully, for sailors have a notion, that if the corposant rises in the rigging, it is a sign of fair weather, but if it comes lower down, there will be a storm“.
Many Russian sailors have seen them throughout the years. To them, they are „Saint Nicholas“ or „Saint Peter’s lights“. They were also sometimes called St. Helen’s or St. Hermes‚ fire, perhaps through linguistic confusion.
Nikola Tesla created St. Elmo’s Fire in 1899 while testing out a Tesla coil at his laboratory in Colorado Springs. St. Elmo’s fire was seen around the coil and was said to have lit up the wings of butterflies with blue halos as they flew around.
Shortly before the crash of the Luftschiffbau Zeppelin’s Hindenburg in 1937, Professor Mark Heald of Princeton saw St. Elmo’s Fire flickering along the airship’s back a good minute before the fire broke out. Standing outside the main gate to the Naval Air Station, he watched, together with his wife and son, as the airship approached the mast and dropped her bow lines. A minute thereafter, by Mr. Heald’s estimation, he first noticed a dim „blue flame“ flickering along the backbone girder about one-quarter the length abaft the bow to the tail. There was time for him to remark to his wife, „Oh, heavens, the thing is afire,“ for her to reply, „Where?“ and for him to answer, „Up along the top ridge“ – before there was a big burst of flaming hydrogen from a point he estimated to be about one-third the ship’s length from the stern.
Accounts of Magellan’s first circumnavigation of the globe refer to St. Elmo’s fire being seen around the fleet’s ships multiple times off the coast of South America. The sailors saw these as favorable omens.
On August 26, 1883, the British warship Charles Ball sailing the Sunda Strait en route to Hong Kong came within 20 km of the exploding Krakatau volcano and witnessed a great deal of static electricity in the atmosphere, generated by the movement of tiny particles of rocks and droplets of water from the volcano’s steam, which caused spectacular brush discharges taking place from the masts and rigging of the ship.
Among the phenomena experienced on British Airways Flight 9 on June 24, 1982 were glowing light flashes along the leading edges of the aircraft, which were seen by both passengers and crew. While it shared similarities with St Elmo’s fire, the glow experienced was from the impact of ash particles on the leading edges of the aircraft, similar to that seen by operators of sandblasting equipment.
The ill-fated Air France Flight 447 flight from Rio de Janeiro–Galeão (GIG) to Paris Charles de Gaulle Airport in 2009 is understood to have experienced St. Elmo’s fire 23 minutes prior to crashing into the Atlantic Ocean. However, the phenomenon had no effect on the disaster itself. 
Visual aspect of St. Elmo’s fire
Here are some pictures and videos I found trustworthy. I gathered them with a (non-exclusive) focus on any view from an aircraft.
I numbered them in order to more easily reference to them in the next sections.
After having carefully looked at them, let us examine if St. Elmo’s Fire (SEF) might be a viable explanation for most foo-fighters.
St. Elmo’s fire is actually a plasma stemming from the ionization of air (namely oxygen and nitrogen) caused by a strong static electricity.
Following the emission spectrum of these species, the „fire“ looks blue-violet most of the time. I also found it more rarely described as white or green.
But I never found any example of its looking yellow, orange or red. Yet plunging into the foo-fighter literature reveals that these are the very colors of a great proportion of intriguing fireballs which paced aircrafts and maneuvered around them during World War II.
Consequently, this fact alone considerably limits the explanatory scope of the hypothesis in question.
Another necessary condition for St. Elmo’s fire accounting for typical foo-fighter sightings would be its ability to be perceived as distinct balls of fire moving along or around a plane during at least one minute.
What is more, if an electrical phenomenon (as in the above pictures) had been visible around the plane, there is no doubt that this would have been indicated in at least a significant number of all foo-fighter reports. But to the best of my knowledge, we find nothing of the sort. In that case, it seems really reasonable to assume that absence of evidence is evidence of absence.
So, for Saint Elmo’s fire to be a reliable explanation, it must be able to appear to pilots during at least one minute as distinct objects in the ABSENCE of any manifestation which would be obviously associated to lightning and electricity.
In all the reliable literature I read on this topic, I didn’t find any case like this.
In all the pictures and videos shown above, SEF appears as a kind of lightning cluster rather than as a distinct object, let alone a spherical one.
„St. Elmo’s Fire is a type of continuous electric spark called a „glow discharge.“ You’ve seen it many times before, since it is almost exactly the same as the glows found inside fluorescent tubes, mercury vapor streetlights, old orange-display calculators and in „eye of the storm“ plasma globes. When it occurs naturally, we call it St. Elmo’s Fire, but when it occurs inside a glass tube, we call it a neon sign. „
It seems extremely convoluted to try to forcefully fit a ball moving along with and often relatively to the plane to this:
Amateurish depictions of „St. Elmo’s balls“
While I didn’t discover any reliable source mentioning SEF appearing as distinct objects, I found several anonymous individuals calling round or spherical luminous phenomena „St. Elmo’s fire“.
Of course, this „naming“ by amateurs give us absolutely no evidence that the phenomenon known to scientists as St. Elmo’s fire can take on this kind of shape.
The Wikipedia article itself mentions that lay people can readily mistake ball lightnings for SEF and the same probably holds true for other causes of misidentification.
„In Two Years Before the Mast, Richard Henry Dana, Jr. describes seeing a corposant in the Horse latitudes of the northern Atlantic Ocean. However, he may have been talking about ball lightning; as mentioned earlier it is often erroneously identified as St. Elmo’s fire: „There, directly over where we had been standing, upon the main top-gallant mast-head, was a ball of light, which the sailors name a corposant (corpus sancti), and which the mate had called out to us to look at. They were all watching it carefully, for sailors have a notion, that if the corposant rises in the rigging, it is a sign of fair weather, but if it comes lower down, there will be a storm“. „
What is more, as James Dale Barry, a leading scientist investigating ball lightnings wrote: „A characteristic distinction between St. Elmo’s Fire and ball lightning is the apparently independent motion of the latter. Although St. Elmo’s Fire has been observed to move about, it may move along a conductor, sometimes pulsating as it moves, but it does not free itself from the conductor. Thus, it does not exhibit the descending, hovering, or flying motions that are common to ball lightning. „
And the same holds true for innumerable foo-fighters observed during the last Great War.
In the end, we have excellent grounds for concluding that St. Elmo’s fire does NOT give rise to balls of light moving in the air.
If anyone disagree, I’d be very thankful if he or she could provide us with a well-documented case where this was observed to happen nonetheless.
In the present post, I limited myself to one possible generic explanation of foo-fighters, namely St. Elmo’s fire.
We have seen that it offers a terrible match to the typical manifestation of the phenomena. Using it as a compelling explanation seems akin to try to fit a cube into an open sphere during a test of logic.
While there might be some foo-fighter cases where SEF could be a viable explanation, they seem to be very rare and I haven’t come across one until now.
Now, nothing I have argued here rules out the possibility that foo-fighters might very well be natural phenomena of other kinds.
Indeed, the ball-lightnings mentioned above might potentially account for some sightings.
In an earlier post, I explained how scientists had tried to dismiss ball-lightnings as a hallucination using arguments scarily similar to those used by UFO-debunkers.
In the next months, I shall analyze interesting foo-fighter incidents individually.
Appendix: pseudo-skepticism in action
At this point, I feel I have the duty to quickly go into the assertions of a debunker called the „Iron Skeptic“ (IS).
He set out to explain away the largest part of the Foo-Fighter phenomenon through St. Elmo’s fire. My comments are written in orange.
What was the official explanation? Static electricity. For whatever reason, electricity builds up in the fuselage of an aircraft and it starts to discharge. Of course, during the war, the Americans had some pretty important issues on the table, so once we realized that there was no proof the Foo Fighters were Axis weapons, our scientists went back to what they were doing and didn’t exactly break their backs trying to explain this goofy little problem.
I can understand that and I can respect that. If the wingtips of your bombers glow a little once in a while, as long as the wingtips do not proceed to break off of the rest of the airplane, it’s hardly a wartime priority.
Here, IS correctly describes what one would have expected if Foo-Fighters had been merely St. Elmo’s Fire. Of course, pilots saw MOVING BALLS and not „glowing wingtips“.
However, this lack of serious study at the time now results in every historical revisionist, occultist, and general nutcase in the woodwork to make claims about aliens, Atlantis, Bigfoot, so on and so forth.
Let me change gears for a moment. Back during the historical period on which every romance novel is based, that is to say, back when human beings made a habit of sailing the oceans in giant, wooden sailing vessels, they had a problem with Foo Fighters. Lights would dance around the masts of the ship, they would trail the vessel, they would wiggle about and perform aerobatics in the air.
This sentence will give you time to gather your jaw off of the floor, where it has surely dropped after this revelation. The aliens have always been with us! They spied on our aircraft during the War in the same manner by which they spied on our Galleons and Frigates as they were chasing down whales to kill! Well, disassemble that tin-foil hat and go back to using it for wrapping luncheon meats: no such thing happened. Since they didn’t have comic books in those days, sailors named the lights after the only other book everyone had read (the bible) and christened the phenomenon St. Elmo’s Fire. St Elmo, also called Erasmus, was one of the fourteen holy helpers, and was martyred. He protects not just sea-going vessels, but helps out with stomach cramps, if you’re into that sort of thing.
Anyway, back to the topic at hand: St Elmo’s Fire is nothing more than static electricity building up in the rigging of a ship before a thunderstorm. To their credit, UFO enthusiasts rarely claim that these ocean-going Foo Fighters were actually alien spacecraft, yet, when the same thing happens to airplanes in the modern day, they refuse to accept the simple explanation and prefer one based on space people.
The case isn’t as clear cut as this, of course. The UFO enthusiast can raise a number of questions about the differences between Foo Fighters and St Elmo’s Fire that seem, at first glance, to invalidate any link. Let’s look at them.
First, they ask why Foo Fighters appeared only during World War Two, and not in the modern day. Modern airplanes are vastly different than the propeller driven craft in use during the war. They are made with different materials, they come in different shapes, and they fly at much faster speeds. Any one of these variables would be enough to, perhaps, change the probability of a static electricity buildup.
IS doesn’t provide the slightest evidence for his speculation that current aircrafts would no longer allow the occurrence of certain electro-magnetic phenomena besides them.
Actually, we know it is completely wrong as far as SEF is concerned. St. Elmo’s fire still appears on modern planes as illustrated by the pictures above. And this doesn’t look at all like the descriptions of foo-fighters.
But there are still propeller aircraft in service, and people regularly fly around in vintage airplanes, so why don’t we see more cases of it? Well, I’m no statistician, but consider this: during World War Two we had an enormous number of airplanes in service. A small fraction of these airplanes reported seeing Foo Fighters. Today, we have a tiny fraction of that number of airplanes still flying about. So therefore, we should only be seeing Foo Fighters near a tiny fraction of a tiny fraction of airplanes. That seems like a perfectly reasonable explanation as to why Foo Fighter sightings fell so precipitously after the war: fewer airplanes flying means fewer opportunities for Foo Fighters to form.
As we saw, the sightings of St. Elmo’s fire did NOT cease after the war. It has always been observed around aircrafts and airships, both before and after WWII.
And it is most likely utterly unrelated to the large majority of Foo-Fighters.
St. Elmo’s Fire is sort of lethargic: it kind of hangs around the masts of a ship and glows for a little while, then it disappears. The Foo Fighters move around and do tricks. Consider this: a Galleon, or Frigate, or Schooner, or what have you, travels at something like ten miles an hour. World War Two-era fighter and bomber aircraft travel at hundreds of miles per hour. Imagine you’re a pocket of static electricity. In one case, you’re being rocked by the gentle winds of a slow-moving ship; in the other, you’re rocketing through the atmosphere several dozen times more quickly. Under which circumstance do you think you’re going to move around more? With the slow-moving air around ships and the fast-moving, complex air currents around aircraft, it’s completely logical that if St Elmo’s Fire is going to form around an airplane, it’s going to get bounced around more.
At this point, it is worth quoting again James Dale Barry, a leading scientist investigating ball lightnings:
„A characteristic distinction between St. Elmo’s Fire and ball lightning is the apparently independent motion of the latter. Although St. Elmo’s Fire has been observed to move about, it may move along a conductor, sometimes pulsating as it moves, but it does not free itself from the conductor. Thus, it does not exhibit the descending, hovering, or flying motions that are common to ball lightning. „
The higher speed of aircrafts doesn’t cause St. Elmo’s fire to look like moving balls. It makes it look like a fluctuating cluster of small lightings, as can be visualized in the pictures and videos I included above.
Debunkers keep calling themselves the defenders of science and rationality. Alas, their deeds all too often fail to match up.
This pseudo-skeptic has constantly confused his ungrounded speculations with compelling explanations and even failed to thoroughly read the literature on St. Elmo’s fire. Had he done that, he would have been aware that SEF doesn’t take on an orange, yellow and red color and that it doesn’t resemble moving spheres of energy such as ball lightnings.
When debunkers tell you they are capable of explaining EVERY anomalous event they’ve stumbled across, what they most often mean is that they could always resort to groundless speculations and far-fetched hypotheses for creating the illusion of an explanation like-minded people find convincing.