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A group of scientists led
by researchers from the University of Rochester and North Carolina State
University have, for the first time, sent a message using a beam of neutrinos—nearly
massless particles that travel at almost the speed of light. The message was
sent through 240 m of stone and said simply, “Neutrino.”
“Using neutrinos, it
would be possible to communicate between any two points on Earth without using
satellites or cables,” said Dan Stancil, professor of electrical and
computer engineering at NC State and lead author of a paper describing the
research. “Neutrino communication systems would be much more complicated
than today’s systems, but may have important strategic uses.”
Many have theorized about
the possible uses of neutrinos in communication because of one particularly
valuable property: They can penetrate almost anything they encounter. If this
technology could be applied to submarines, for instance, then they could
conceivably communicate over long distances through water, which is difficult,
if not impossible, with present technology. And if we wanted to communicate
with something in outer space that was on the far side of a moon or a planet,
our message could travel straight through without impediment.
“Of course, our
current technology takes massive amounts of high-tech equipment to communicate
a message using neutrinos, so this isn’t practical now,” said Kevin
McFarland, a University
of Rochester physics
professor who was involved in the experiment. “But the first step toward
someday using neutrinos for communication in a practical application is a
demonstration using today’s technology.”
The team of scientists
that demonstrated that it was possible performed their test at the Fermi
National Accelerator Laboratory (Fermilab), outside of Chicago. The group has submitted its findings
to Modern Physics Letters A.
At Fermilab the
researchers had access to two crucial components. The first is one of the
world’s most powerful particle accelerators, which creates high-intensity beams
of neutrinos by accelerating protons around a 2.5-mile-circumference track and
then colliding them with a carbon target. The second is a multi-ton detector
called MINERvA, located in a cavern 100 m underground.
The fact that such a substantial
setup is necessary to communicate using neutrinos means that much work will
need to be done before the technology can be incorporated into a readily usable
form.
The communication test
was done during a two-hour period when the accelerator was running at half its
full intensity due to an upcoming scheduled downtime. Regular MINERvA
interaction data was collected at the same time the communication test was
being carried out.
Today, most communication
is carried out by sending and receiving electromagnetic waves. That is how our
radios, cell phones, and televisions operate. But electromagnetic waves don’t
pass easily through most types of matter. They get blocked by water and
mountains and many other liquids and solids. Neutrinos, on the other hand,
regularly pass through entire planets without being disturbed. Because of their
neutral electric charge and almost non-existent mass, neutrinos are not subject
to magnetic attractions and are not significantly altered by gravity, so they
are virtually free of impediments to their motion.
The message that the
scientists sent using neutrinos was translated into binary code. In other
words, the word “neutrino” was represented by a series of 1’s and
0’s, with the 1’s corresponding to a group of neutrinos being fired and the 0’s
corresponding to no neutrinos being fired. The neutrinos were fired in large
groups because they are so evasive that even with a multi-ton detector, only
about one in ten billion neutrinos are detected. After the neutrinos were detected,
a computer on the other end translated the binary code back into English, and
the word “neutrino” was successfully received.
“Neutrinos have been
an amazing tool to help us learn about the workings of both the nucleus and the
universe,” said Deborah Harris, Minerva project manager, “but
neutrino communication has a long way to go before it will be as
effective.”
Minerva is an
international collaboration of nuclear and particle physicists from 21
institutions that study neutrino behavior using a detector located at Fermi
National Accelerator Laboratory near Chicago.
This is the first neutrino experiment in the world to use a high-intensity beam
to study neutrino reactions with nuclei of five different target materials,
creating the first side-by-side comparison of interactions. This will help
complete the picture of neutrinos and allow data to be more clearly interpreted
in current and future experiments.
