The neutrino messengers
In 1844 Samuel Morse sent a telegram from Washington, D.C., to Baltimore using pulses of electrons to encode “What hath God wrought.” Now that message has gotten a reply, courtesy of physicist Kevin McFarland and a team of his colleagues.
“Neutrino” was the team’s tongue-in-cheek response, broadcast in the first-ever message carried by these ghostly particles. It was supposed to be “neutrinos,” but someone goofed and cut off the “s.”
This offbeat project started with Daniel Stancil, an electrical engineer at North Carolina State University in Raleigh. He’s been thinking about how to use all sorts of particles—including neutrinos and hypothetical entities called axions—to communicate over long distances.
“I chose neutrinos because they have a pretty significant advantage over axions,” says Stancil. “They’re known to exist.”
Stancil asked McFarland whether it would be possible to send such a message using the neutrino experiment MINERvA at the Fermi National Accelerator Laboratory just outside of Batavia, Ill. McFarland liked the idea but worried that it would distract from the experiment’s primary goal.
“When you’re doing something that’s very pie in the sky like this, something that’s so far off the main science mission, you have to think about whether it’s worth it,” says McFarland, of the University of Rochester in New York.
After deciding that a proof-of-principle trial run wouldn’t take long, the physicists created bursts of neutrinos, each with 100 million particles. These pulses traveled to a 170-metric-ton detector a kilometer away that translated them like Morse code, into the letters of the message.
Neutrinos aren’t exactly the most efficient way to send a message. Just making the particles required 100 gigawatts of power. But neutrinos can zip through Earth’s interior unmolested, potentially delivering messages from one side of the planet to the other—or to places difficult to reach with conventional communications, such as submarines deep underwater. — Devin Powell
The beam goes on
Credit: Fermilab, adapted by Stephen Egts
The neutrino beam used by Fermilab scientists to send a message (above) is a key part of larger physics experiments. Most neutrinos pass right through the detector that picked up the message, called MINERvA, but the few that are caught provide information about what happens when a neutrino strikes an atom’s nucleus. That information helps physicists understand what happens later, when the particles arrive at a mine deep underground in Minnesota 735 kilometers away. There, a detector called MINOS looks for signs of neutrinos shape-shifting from one to another of their three flavors during flight.