The scientific explanation isn't nearly as poetic as the story the Inuit share of souls of those who died from loss of blood, playing a ghoulish version of soccer with a walrus skull that chatters as its tusk slashes at the players. Or the heavenly wedding ceremony of Estonian folk tales. Or the dream-time feast fires of the Australian Aborigines. But science has a certain elegance all the same.

At this point, the technical elements are still somewhat theoretical and little research is currently being conducted. But a small group of international collaborators is convinced that traditional knowledge from around the poles and centuries of anecdotes from reliable sources have a basis in fact. While these stories don't agree on one particular sound, the it's usually described as a rustling or faint whistling. Or, as the poet Service put it so elegantly, like bruised silk.

Like many breakthroughs in the sciences, the understanding of what is known as geophysical electrophonics has come about almost by accident. In fact, this story of discovery doesn't even begin in the Northern Hemisphere at all but at the bottom of the world, with the appearance of a rare fireball that exploded above Australia in 1978.

On April 17 that year, the pre-dawn sky above Sydney lit up about 90 minutes early as a meteor fireball sliced through the atmosphere on its way to an explosive rendezvous with the South Pacific ocean. Colin Keay, at the time an astronomer at the University of Newcastle and local meteor expert, got a call from a museum asking for his help locating the meteorite.

"A lot of people were out going about their business and they saw the whole sky light up like it was daylight. It was huge thing like another sun cross the sky," Keay recalls.

Hopes to find the object and learn more about it faded quickly. A check of the object's trajectory made it clear that it had missed Australia entirely. If it did reach the surface, it would have been far out to sea. So much for that.

But Keay's curiosity was piqued by the first-hand stories he heard witnesses tell during his efforts to track down the fireball's path. "It was struck by the fact that one in four actually claimed they actually heard it go by," Keay says. "And I first of all trotted out the standard meteor-scientist explanation that back in the time of Edmund Halley they had concluded it was psychological."

Halley, the namesake of the famous comet, had taken a similar interest in another fireball more than 250 years previously. He, too, had come across numerous reports of an accompanying hissing sound, which he had dismissed as "the effect of pure fantasy" for want of any possible mechanism to explain how people could be hearing the passing of a meteor.

Keay did likewise, attributing the reports to wishful thinking: a rocket goes "swoosh," goes the theory, and so should a meteor. But after four or five people gave him the same story, Keay began to wonder if perhaps he, Halley and dozens of other astronomers over the centuries had been too hasty.

"There was one lady in particular, a cleaning lady who was transparently honest about the whole thing that I just stopped and thought: here am I dismissing this as psychological and here's this lady with no preconceptions, no hangups, perfectly fine, and she just says it sounded so real, and the thing that astonished her was her friend on the other side of the car -- they were cleaning ladies getting out of car to clean a supermarket -- didn't hear a thing."

For Keay, the consistency of the reports was as puzzling as the idea of meteoric sounds themselves. "So I stopped trotting out the psychological explanation," he says. "Because, of the cases I investigated, two of them were from people who heard the sound before they saw the light. Now, that's not psychological, that's precognition. And I don't believe in precognition, so that really suggested I get my teeth stuck into it."

The problem was the laws of physics would seem to preclude hearing a meteor, let alone hearing it before it passes by. Meteors typically enter the atmosphere and evaporate hundreds of kilometres up, so any sounds should only be heard long after it's seen. The out-of-synch effect is similar to the time lag between seeing a high-flying jet and hearing it, but much more exaggerated.

The aurora borealis -- or its mirror-image, the aurora australis, in the Southern Hemisphere -- offers the same dilemma. Shimmering no less than 70 kilometres up, the thin atmosphere at those altitudes makes adequate transmission of any noise virtually impossible. In space, after all, there is no rustle and whisper. There is no sound at all.

Keay, taking a leave of absence to work with colleagues in Canada at the National Research Council in Ottawa, eventually came up with a mechanism to explain the meteor sound mystery, and along the way, that of the aurora sounds. His theory, published in the prestigious journal Science in 1980, is remarkably simple. All one has to do is get past the common misconception that matter can exist in only three states: solid, liquid or gas.

In fact, more than 99 percent of the universe exists as plasma, a fourth state similar to an ultra-hot gas and that consists purely of ionized particles like electrons and protons. Plasma's most important characteristic is that it can conduct electricity. Lightning, for example, is a discharge of plasma. Plasma also gives a fluorescent light tube its glow.

Some meteors, it turns outs, heat the upper atmosphere so much that the gases turn into an electrically charged plasma that gets caught in the Earth's magnetic field. The interaction between the plasma left behind to cool in the meteor's wake and the magnetic field produces electromagnetic radiation -- very long wavelength radio waves -- which are broadcast down to the surface.

In the case of the aurora, the source of the plasma is the sun. When the electrons in the solar wind hit the Earth's magnetic field, most of them are deflected away from our planet (making life possible by sparing us from a barrage of lethal radiation) but some are trapped in the field and funneled toward the north and south poles. When the particles hit atoms of oxygen and nitrogen in the atmosphere, the result is a visible glow -- the aurora -- and, presumably, radio waves.

Of course, you can't hear radio waves. If those waves oscillate in the right frequency range, however, you might be able to hear the effect they have on objects closer at hand. In the same way that a rubbed balloon or comb can make hair stand on end, the static electricity produced by radio waves from a meteor's wake or the aurora can make small objects rise and fall in what is called transduction. In effect, we should be able to hear the effects of the aurora, though not the aurora itself.

A series of experiments Keay conducted at the University of Western Ontario in the 1980s showed that electromagnetic fields could be transduced by, of all things, hair. He put 43 volunteers in a soundproof chamber and bombarded them with harmless electromagnetic radiation comparable to what would be given off by the aurora.

"Two of them were secretaries in the department that had the then-fashionable Afro hairstyle and the hairs on their head were rubbing together at the frequency of the electrostatic voltage," Keay says. "The other one was a fellow who became head of the department, who had very, very fine, fluffy hair, which was the kind of hair which popped straight up when you put him under an electrostatic generator ... his hair was rising and falling and rising and falling at the audio frequency and making a swishing sound."

Since then, analysis of a Swedish audio recording of what had been thought to be the Northern Lights themselves turned out to be the transduction of vibrations induced in the recording antenna itself. The case for the transducer effect is now stronger than ever, and over the years Keay has managed to bring many former skeptics onside.

Dr. Martin Beech, an astronomer at the University of Regina's Campion College, had also originally dismissed reports of sounds from meteors and the aurora as impossible. Like his fellow astronomer, though, he has come to similar conclusions about the numerous eye-witness accounts. There just seems to be too many similar stories to chalk it all up to imagination.

"We've not really investigated in any great detail," says Beech, one of the strongest supporters of Keay's theory. "But it seems to be a process that's linked in the same way."

He and Keay have their own prime suspects for the transducers that are producing the sympathetic vibrations linked to the Northern Lights. Chief among them are pine needles. "It's not clear, but they do seem to be a good resonator," says Beech, who has been trying to record the sounds of meteors for years. "They're small enough, light enough."

Other candidates for sympathetic vibrating materials include grass or other dry vegetation, and metallic objects, such as a pair of glasses. Getting a recording to match against witness accounts is proving difficult, however.

"It's even harder than the Loch Ness monster to get a handle on it," Keay says.

-30-

Return to the Cyamid Front Page