OPERA melodrama: Why the neutrino matters

News has been traveling around the world at the speed of light since researchers at the Oscillation Project with Emulsion-tRacking Apparatus (OPERA) have announced and re-confirmed their controversial results that measured neutrinos traveling faster than the speed of light [1]. This is an interesting, but probably incorrect, claim.

 

The more fascinating aspect about the experiment was that the researchers at OPERA were not trying to measure the speed of neutrinos. Rather, they were measuring how neutrinos change properties as they pass through matter. Yet, why are scientists so interested in neutrinos in the first place?

 

Neutrinos, first theorized by Wolfgang Pauli in 1930 and first detected in 1956, are low mass, electrically neutral subatomic particles that are created in beta decay. The low mass and neutral properties of neutrinos allow them to pass through most forms of matter unaffected by gravity and other electromagnetic forces [2].

 

Scientists are hoping that neutrino detectors on earth and in satellites will allow the collection of data on far off phenomenon where light is obscured and matter is trapped (for example, in supernovas and the center of the galaxy). However, this is not the only use for neutrinos. Scientists have theorized several potential uses for the ghostly particle.

 

Since neutrinos are produced in the radioactive decay of isotopes, Lasserre and colleagues have proposed using neutrino detectors to detect illegal nuclear reactor programs [3]. Current detection methods used by the International Atomic Energy Agency (IAEA), the United Nations organization tasked with policing nuclear programs across the globe, range from monitoring nuclear sites through fiber-optic networks, closed-circuit television and field investigations. Yet, these methods are time-consuming (especially field work) and are unable to detect secret nuclear reactors by nations that do not recognize the IAEA.

 

The proposal by Lasserre and colleagues works off of the knowledge that nuclear reactors will release a known amount of neutrinos at certain power levels. When an illegal nuclear site is believed to exist, a several hundred ton neutrino detector could be deployed near the site. If the neutrino levels are higher than expected, three other neutrino detectors can be deployed and used to pinpoint the approximate location of the nuclear reactor.

 

Of course, there are problems. There are always problems. Neutrinos are a naturally occurring particle. Billions upon billions of neutrino emitted by the sun pass through the earth each day. The neutrino detectors proposed by Lasserre and colleagues will need to take naturally occurring neutrinos into account. Also, neutrino detectors large enough to detect illegal nuclear reactor sites will be prohibitively expensive. For the cash-strapped United Nations, this technological breakthrough might be out of reach.

 

Another future-tech use for neutrinos is to use the particle for communication. Since neutrinos are mostly unaffected by matter, they can travel through thousands of feet of ground or water without deflection. Moreover, it is calculated that neutrinos could carry up to ten bits per second [4]. This means that in the future, neutrinos and neutrino detectors could be used to communicate with submarines and other deep underground expeditions where radio signals, which are often deflected by metal cages or a thick forest, cannot penetrate.

 

Yet, the same problem occurs. Neutrino production and neutrino detection is still very expensive. We most likely will not see any of these technologies in the near future. Neutrino research and technology will be reserved for the massive budgets of militaries and the few lucky labs, like CERN and OPERA, who have the monetary support and equipment to study these odd particles.

 

So, neutrinos have several future applications that are of tremendous interest to scientists. Now, all we need is for this nonsense about faster than light travel to be rejected by the scientific method, so the researchers at OPERA can continue to study and unravel the mysteries of that tiny neutral particle, the neutrino.