Voice of God The New Scientist AND THE VOICE SAID...
Go home, slaughter your first-born and make sacrifice
unto me. Ha! Just kidding. Still, had you fooled for a minute, didn't
I?
I was at a party in downtown Oakland when I first heard
about the Voice of God. It was the usual mix - a few intellectuals
from Berkeley and Stanford, the gracious host and hostess and a gaggle
of greedy jouranlists, of whom I was one. The conversation was
highbrow and stilted but the food was
plentiful, so I stayed to chat. It was an innocuous, forgettable
evening, except for one thing, a short conversation with an expert in
laser optics from Stanford University. His extraordinary tale left me
spinning.
It involved a clandestine military project with a goal
so outrageous that, even now, it is difficult to comprehend. The story
was set in the late 1980s, at an undisclosed military research
facility hidden in the New Mexico
desert. Here, researchers working with high-power laser weapons
discovered that they could create a glowing ball of fire in the sky by
crossing the beams of two powerful infrared lasers. The beams were
invisible to the naked eye, but where they intersected, their electric
fields became so intense that they ripped apart molecules in the air,
creating a plasma - a luminous
mix of high-energy ions and electrons.
By moving the laser beams around the sky, the
researchers found they could shift the plasma ball back and forth at
very high speed. They even discovered that by switching the beams on
and off quickly and redirecting them to different spots, they could
maintain several plasma balls in the air
at the same time. At night, they demonstrated their skills, flying
their glowing creations in formation high above the cold desert.
These shows were noisy events. When the intense electric
field rips one molecule apart, it releases electrons that smash into
its neighbors, breaking them apart and releasing more electrons. This
develops into a cascade known as inverse bremsstrahlung, and the
result is explosive. Literally. The pressure wave it creates can reach
thousands of atmospheres.
Even the smallest shock waves sound like firecrackers, and by rapidly
pulsing the plasma balls on and off, the researchers created a stream
of shock waves that merged together to form a continuous loud hiss or,
depending on the frequency of the pulsations, a crackle.
Now the tale gets more interesting. According to my
fellow party guest, the team discovered that by modulating the
frequency and intensity of the hissing sound, they could create a
voice-like effect. The result was a highly- manoeuvrable, glowing ball
of plasma that seemed to appear out of
thin air - a ball of plasma that could "talk". The U.S. military named
the technology the Voice of God and classified it top secret. My
contact said that he had heard of plans to use the device as a
psychological weapon during the Gulf War in 1991, but that for some
reason these plans were never realised.
And there the tale ends. After the party, I contacted
the researcher for more details but he was unable, or possibly
unwilling, to provide them. I was stuck with nothing to follow up - no
military facility, no contact numbers, no names. Nothing but the idea
itself.
So is it possible? Does the technology really exist to
create glowing balls of plasma that talk? Thus began a quest to
discover not whether the Voice of God exists, but whether it could
exist.
My first useful interview was with Leik Myrabo, a
professor of engineering physics from Rensselaer Polytechnic Institute
in New York State who works with the Propulsion Directorate at the
U.S. Air Force Research Lab at Edwards Air Force Base in California.
Myrabo is no stranger to the way
lasers can break down the atmosphere to form a plasma. He uses the
effect to propel prototype spacecraft into the air on the tip of a
laser beam (New Scientist, 10 January 1998, p 34). But after hearing
my story, he sounded skeptical: "I'm not saying it's impossible, but
it would be difficult."
The first problem, he told me, would be generating the
required intensity of several gigawatts per square centimetre. The
laser Myrabo uses is the most powerful of its kind in the U.S. Known
as the Pulsed Laser Vulnerability
Test System (PLVTS), it generates a rapid series of infrared pulses,
each one lasting only 18 microseconds. One pulse has the energy of 450
joules. And the PLVTS can generate 20 of them every second. This gives
an average power of 9 kilowatts but the only way Myrabo can create
inverse bremsstrahlung is by focusing this beam down to a point. In
this tiny spot, the power density is millions of times higher than in
the unfocused beam, and the air explodes. "It sounds like a
firecracker going off," he said.
The focusing optics in Myrabo's propulsion system are
built into his prototype spacecraft: the back of the craft is a curved
mirror. But the Voice of God would not have the benefit of a curved
mirror or a lens floating in the air, and any focusing system built at
the laser end of things would have to be huge to operate over long
distances. There's another problem: crossing two laser beams would be
of little value, according to Don Walters, an atmospheric physicist at
the Naval Postgraduate School in Monterey, California. "Crossing the
beams only doubles the intensity but you'd need to increase it by many
orders of magnitude," he said.
Without the ability to focus the beams, Walters and
Myrabo agree that Voice of God technology would require lasers vastly
more powerful than any that are easily available today. "I suppose
NOVA could do it," Walters told me, referring to the world's most
powerful laser at the Lawrence Livermore
National Laboratory near San Francisco. "But that's the size of an
entire building."
But Walters didn't dismiss the idea outright. "It seems
a bit far-fetched, but I suspect it could work in the lab with just
one laser," he said. In fact he went as far as to say that creating a
laser-induced plasma should be easy in many labs but that the plasma
can only be produced a few centimetres in front of the lenses that
focus the beam.
Controlling the frequency of the pulses would be
straightforward too, though changing their intensity would be tough.
"But I wouldn't be suprised if somebody had already done it," he said.
After many telephone calls and several interviews, the concensus
seemed to be that the Voice of God was possible in the lab but very
difficult to produce in the sky.
Finally, I contacted John Pike, a spokesperson for the
Federation of American Scientists in Washington DC and a long-time
observer of the U.S. military machine. "I've never heard of it," he
said, pointing out that it sounded a bit like a story that had
circulated soon after the Gulf War. Somebody, he said, had suggested
that beaming a short film of an imitation
Allah saying "Go home" onto the low clouds over Kuwait, but apparently
the plan was never put into action.
So what about the Voice of God? Pike wasn't particularly
impressed with the idea. "It sounds like a project that didn't have
the benefit of adult supervision," he joked. Conceivably true, I
thought, but hardly grounds to rule out the possibility. After all,
the U.S. military has tested a piloted
flying saucer, experimented with mind control, and attempted to
recreate "Star Wars" technology in space. Would the Voice of God
really be a step too far?
Given the way the extraordinay keeps becoming ordinary,
I doubt it. And even if the idea hasn't been tried before, somebody is
almost certain to try it now...
by Justin Mullins
December 25, 1999