by Amy (originally published in Socialist Review Nov 2011)
The scientific world has been shaken by developments in the OPERA
(Oscillation Project with Emulsion-tracking Apparatus) collaboration.
Researchers from over 48 different institutions across the world have
recorded neutrinos travelling 60 nanoseconds faster than the speed of
light in a vacuum between a source and a detector.
finding could overturn one of the most fundamental laws in modern
physics - that nothing travels faster than the speed of light.
Neutrinos are fundamental particles with a very small mass, and
are electrically neutral, meaning they rarely interact with other
matter. Billions of neutrinos pass through the Earth every second. The
majority of neutrinos that pass through the Earth are generated in the
sun, but they can also form from the decay of radioactive elements such
as U-238, found in nuclear reactors, supernovas, and, as happened in the
OPERA experiment, particle accelerators.
Using a detector situated 1400m underground in the Gran Sasso
National Laboratory in Italy, the OPERA experiment was designed to study
a beam of neutrinos produced 731km away at CERN (the European
Organisation for Nuclear Research) in Switzerland. The results appear to
be accurate. Neutrinos travelling faster than the speed of light have
been recorded for more than 16,000 events in the last two years. The
OPERA collaboration seem confident in their results thanks, in part, to
new methods using Global Positioning System (GPS) technology to
synchronise the clocks at CERN and Gran Sasso, and also by using GPS to
get an accurate measurement for the distance between the source of the
neutrinos and the detector.
Previous experiments which have attempted to find particles
travelling faster than the speed of light have come away empty-handed. A
pulse of neutrinos generated in a nearby supernova (exploding star),
and the flash of light seen from the supernova, for example, arrived
within hours of each other. If all neutrinos can achieve faster than
light speeds then the neutrino pulse should have arrived years before
the flash of light. Since the results were announced in September many
have sought to explain the observations or find fault with the method
used by the OPERA group. Whether the clocks at the source and the
detector have been synchronised correctly is a key issue. One suggestion
is that gravitational pull at CERN is stronger than at Gran Sasso,
meaning, according to Einstein's general theory of relativity, clocks at
CERN would run slower than in Italy.
Many more ideas are likely to surface in the coming months. The
law that nothing travels faster than the speed of light, the cornerstone
of Einstein's theory of relativity, is crucial for most physics
developed since 1905. If it is found that neutrinos can travel faster
than the speed of light, this would force us to rethink many areas of
science. Changes in science, both in what we know, and in how science is
done, occur for three main reasons. One is changes to the technology
available to investigate problems. The OPERA experiment used more
accurate methods of measuring time and distance than have been available
in the past, so it may mean that this is the first opportunity we have
had to measure neutrinos travelling faster than the speed of light.
Secondly, who controls technology is important - both in how it
gets used and whether it gets developed in the first place. The
potential for a new technology to improve the world, for example
renewable energy, doesn't necessarily mean that it is developed, if, for
instance, it isn't in the interests of capital to do so.
Finally, the drive to gain a better understanding of the world
can also bring about changes to science. This means going beyond the
dominant ideas at the time, and coming up with new theories that may not
immediately be apparent. To explain the observations seen in the OPERA
experiment may mean rethinking what we currently understand. And new
theories may have to be developed if what we thought to be the laws that
govern the way the universe works are found to be broken on some
Whether this latest result will lead to a rewriting of physics or
is just due to an overlooked factor is currently unknown. It does,
however, give us a useful reminder that our understanding of the
physical world is not complete and that we should not be afraid of new
discoveries which may completely overturn what we currently know.
(and a joke...."we don't serve neutrinos here", a neutrino walks into a bar)