The ICARUS (Imaging Cosmic And Rare Underground Signals) experiment was started in 1977 to study neutrinos. Physicists at the ICARUS experiment in Italy measured the time it took for seven neutrinos to reach a liquid argon-filled detector after they were released from the CERN particle physics lab in Switzerland, 730km (450 miles) away. They found that neutrinos travel at roughly the speed of light, but no faster. The ICARUS experiment is located in the same lab within the Gran Sasso Mountain in central Italy as the OPERA experiment that produced the results which flew in the face of Einstein’s special theory of relativity.
The final nail in the coffin for faster-than-light, or superluminal, neutrinos may well come in May, when all four of the experiments in Gran Sasso – OPERA, ICARUS, Borexino and LDV – will time beams of the particles released from CERN. Neutrinos have been used to send a message for the first time. Although it’s still early days, the ability of these subatomic particles to travel vast distances through almost any material makes them an exciting alternative to radio waves, which are easily blocked by mountains and oceans.
Physicists sent a simple message through 240 metres of stone. These humble first steps show that a completely new means of communication is feasible that would enable links which are not currently possible. To test the system, physicists in the US converted the word ‘neutrino’ into binary code, a series of 1’s and 0’s. A beam of neutrinos from the Tevatron particle accelerator at the Fermi National Accelerator Lab near Chicago was then modulated, with a pulse of neutrinos corresponding to a ‘1’ and no neutrinos corresponding to a ‘0’. The resulting signal was received at the MINERvA neutrino detector in a cavern 100 metres underground, where it was translated back into letters.
Neutrinos (‘little neutral ones’ in Italian), have zero electric charge and an almost non-existent mass, so they rarely interact with matter: they can pass right through Earth. They could provide a means to communicate with nuclear submarines since radio waves don’t travel well through salt water. They could also be used to send messages to a rover or base on the far side of another planet. “In cases where large amounts of matter would need to be penetrated to allow communication, neutrinos could save the day,” says Professor Kevin McFarland, a physicist at the University of Rochester, which led the research. But the ‘neutrinophone’ technology still needs more work to be of practical use.
The very property that makes neutrinos such an exciting prospect in communications, their ability to penetrate matter, also makes them extremely difficult to detect. The MINERvA detector weighs 170 tonnes, not a practical possibility aboard a sub. “The neutrino beams we currently make are not sufficiently intense to send a lengthy message and are difficult to point at a moving target,” says McFarland. “But increasing the beam intensity is one of the main areas that’s being investigated right now.”
This amazing discovery surely is a big breakthrough in the future of communications. Only time will tell how effectively we could use this path breaking technology.