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Hunting for Spooklights

Notes on a Strange World

Massimo Polidoro

Skeptical Inquirer Volume 32.5, September / October 2008

The hot, still night was illuminated by a full moon. The two shadowy figures moving along the empty road wondered if this would interfere with their mission.

“Are you sure you took everything?” asked the slender one.

“Of course!” said the shorter one, who was carrying a backpack. “I checked the inventory. I even took the infrared goggles and a telescopic steel rod.”


“Well . . . as a form of self-defense. You never know.”

The two reached a tall, black gate.

“It’s locked.”

“Hold this,” said the shorter one, handing the backpack to his colleague. After searching it, he took out a large ring with a dozen keys attached.

“Here they are! They assured me that with these there would be no problems.”

“We’ll see. . . .”

One at a time, the short fellow inserted the keys in the keyhole. But not one worked.

“Damn! I knew it. We should have checked first that it worked.”

The road was empty. Only one car had passed since Slender and Shorty stopped by the gate, but it did not slow down. The dark shadows hid them from the light.

“All right, if that’s the way it has to be. . . .”

Slender shined a pocket light into the keyhole. “It’s an old Wally model, there should be no problem.”

Shorty took a leather case out of his pocket and opened it. There were a dozen different lockpicks. One was chosen, and the operation started. “It should be no problem,” puffed Shorty, who was crouched on his legs while trying to pick the lock, sweat dripping from his face. “Yeah, it’s easy when you just hold the light and someone else has to do the dirty job.”

“Cut the chatter. Let’s move along.”

After a few more attempts there was a reassuring “click.” The door was open.

“Quick!” snapped Slender. “Stand up.”

“What . . . ?”

“I said quick, get inside!” Slender pushed his mate in the dark hallway and closed the gate. “Don’t say a word.”

They both hid behind a wall, holding their breath. A police car passed by without stopping.

“That was close!” sighed Slender.

Shorty protested. “Close for what? You make it seem like we are two burglars here!”

Slender smiled. “Yeah, and it’s more fun, isn’t it?”

“We are here on a scientific mission,” continued Shorty. “We are not on a secret hunt to rob lost treasures or something like that.”

Slender turned on his pocket light and did not reply. They were in a dark corridor, but down the hall a door that led to the field outside could clearly be seen. It was open when they reached it.

When they stepped outside, the pocket light was no longer needed. The moon was quite bright, but the field, full of a thousand flickering flames, was more luminous. Quite an unexpected view—surreal but almost romantic. Slender regretted he was there with Shorty and not with his girlfriend.

However, it was indisputable: a cemetery at midnight was a sight not to be missed.

Luminous Fungis and Earth Lights

The two mysterious figures in the story above are my friend and colleague Luigi Garlaschelli and myself. Actually, Luigi is not that short, but I needed an easy descriptor for him. And since he is just a little shorter than I am . . . my apologies, Gigi!

The night visits at the Major Cemetery in Pavia, Italy, took place some time ago when we decided it was time to investigate the “will o’ the wisp” phenomenon. Of course, we obtained official permission from the county administration—“scientific purposes” was the reason we gave for our requested visit. We were quite fascinated by this rare luminous phenomenon, a source of all kinds of supernatural tales.

Also known as ignis fatuus, Latin for temporary fire, will o’ the wisps are in fact said to be ghostly lights, usually seen around graveyards and marshes at night. They look like faint flames or a flickering, glowing fog, usually green, that sometimes appears to recede if approached. Folklorists have collected all kinds of legends related to these mysterious lights, including the fact that they could be some form of spirit lights or have a paranormal origin. Science, however, has precious few facts to offer.

Some have proposed that Armillaria, a parasitic kind of fungi known also as “honey fungus,” could be responsible for some of the apparitions. Some species of Armillaria are bioluminescent and may have been mistaken for will o’ the wisps.

According to another theory, the wisps are nothing more than barn owls with luminescent plumage. Hence, the possibility of them floating around reacting to other lights could explain their strange behavior.

In the 1970s, John Derr and Michael Persinger of the Laurentian University in Sudbury, Ontario, Canada, put forth a theory that these lights may be generated piezoelectrically under a tectonic strain.

The theory suggests that the strains that move faults also cause heat in the rocks, vaporizing the water in them. Rocks and soils containing piezoelectric elements such as quartz (or silicon) may also produce electricity, which is channeled up through soils via a column of vaporized water until it reaches the surface, somehow displaying itself in the form of earth lights. If correct, this could explain why such lights can behave in an electrical and erratic—or even apparently intelligent—manner.

Persinger thinks that his theory can be used to predict the manifestation of earthquakes and, along the way, explain many UFO sightings. “When the specific equations between UFO reports (the contemporary label for luminous events) and earthquakes in the central U.S.A. between 1950 and 1980 were applied to the 19th century (earthquakes were recorded then), there were predictable peaks in the numbers of luminous events for specific years,” says Persinger.

“Although there were no reports of ‘UFOs’ in the historical newspapers, there were reports of ‘odd air ships’ and ‘phantom balloons.’ The massive ‘flap’ of 1897, through several tens of states in the southeastern U.S.A., was followed by one of the largest earthquakes in the region.”

As interesting as this theory sounds, and as interesting as it would be to discover whether UFO “flaps” of the past century have been followed by major earthquakes or not, we wanted to test a different kind of will o’ the wisp. The kind that is said to appear in the presence of freshly buried bodies.

Decaying Bodies

One of the most popular scientific explanations for ghost lights is that the oxidation of hydrogen phosphide and methane gas produced by the decay of organic material may cause glowing lights to appear in the air. And this phenomenon is said to occur more easily in the proximity of “fresh” burials.

Thus, we positioned ourselves, with video cameras rolling, in an area of the cemetery where burials had taken place that same day and a few days before. The idea was to document on film the formation of a will o’ the wisp.

Luigi had even built an aspiring pump that would allow him to “suck” the wisp inside a hermetically sealed container in order to later test its chemical composition in the lab. In fact, Luigi has now been able to replicate the lights in his laboratory at the Department of Chemistry in Pavia with the help of his colleague Paolo Boschetti.

At first, the idea was to test the “cool fire” effect. Luigi explains it this way: “According to one hypothesis, the will o’ the wisp is a sort of cold flame, inconsistent with a normal combustion of methane, as reliable eyewitnesses have reported. ‘Cool flames’ can indeed be generated if vapors of suitable organic compounds (such as ethyl ether) come in contact with a hot surface kept at temperatures around 200–300°C [392–572ºF]. These luminescent pre-combustion haloes are sufficiently cool that a hand or a piece of paper can be put in them without being burned.”

The main objection to this interesting hypothesis is that the necessary vapors are not known components of marsh gases, and the presence of surfaces at such high temperatures is difficult to find in nature.

“It is often stated that the phenomenon originates from the spontaneous combustion of gases generated underground by anaerobic fermentation processes,” continues Luigi. “These gases consist mainly of methane and carbon dioxide. Small amounts of phosphine (PH3) and diphosphine (P2H4) [self-igniting on contact with the air] would act as a ‘chemical match’ for the combustible methane.

“Although this hypothesis is one century old, the presence of PH3 in marsh gases has only recently been demonstrated. If the will o’ the wisp indeed is a hot flame, this conjecture might be correct.” If, on the contrary, a will o’ the wisp is a cool “flame,” then the cold chemiluminescence of some compound naturally occurring in marsh gases appears to be a more appealing explanation.

Luigi reconsidered a century-old experiment conducted by German chemists in which phosphine, oxygen, and an inert gas were fed through three small nozzles at the base of a vertical glass tube. By carefully adjusting the flow of the inlets, a faint flickering luminescence could be seen in the dark near the top of the tube due to the chemiluminescence of phosphine.

Luigi built the necessary equipment with a 500 mL flat-bottomed flask, in which he put some solid phosphorous acid. The flask was stoppered by a silicone septum through which a mixture of air and nitrogen was stored on water within a gas tank and fed by a needle. A second needle in the septum provided for the necessary outlet. The flask was flushed with nitrogen and put on a hot plate that was heated to 200°C (392ºF).

“It works!” shouted Luigi, probably feeling a little like Dr. Frankenstein.

The decomposition of phosphorous acid generated phosphine, and a fog formed in the flask. When the air and nitrogen stream was fed into the phosphine vapors, a faint, pale-greenish light was clearly visible in the darkness.

The success in the lab, however, was not matched by success in the field. We spent the entire night at the cemetery, but nothing happened except buzzing and biting mosquitoes. After that there have been repeated visits to cemeteries, graveyards, marshes, and the like, and Luigi has started to carry with him a very sensitive phosphine detector—a portable Draeger Xam-7000—but so far with no luck.

Being able to reproduce spooklights in a lab is one thing. But to see it up close with your own eyes in a cemetery at night is quite another. Hopes are still high, however. There never is a shortage of fresh burials, and hunting season for will o’ the wisps is always open.

Massimo Polidoro

Massimo Polidoro's photo

Massimo Polidoro is an investigator of the paranormal, author, lecturer, and co-founder and head of CICAP, the Italian skeptics group. His website is at