Conor Manning explains the significance of recent results at CERN
“This theory means that the Universe effectively has a speed limit. Nothing can travel faster than the speed of light.”
“What this all means is that it seems that the result is genuine, unless there was some error in how the experiment was carried out.”
Scientists recently released results that suggested that they had found particles which travel faster than the speed of light. This news, if verified, would have huge implications for the world of Physics and its applications. Why is this result so important?
In 1905, Albert Einstein changed science forever when he introduced the Special Theory of Relativity. This improved on Newton’s Laws, which physicists had been using for more than 200 years. Einstein’s theory is very simple and it says just two things: the laws of physics are the same for all observers moving at a constant velocity away from each other, and the speed of light is the same for any observer.
In simple language, it makes no sense to say that something is travelling with a certain speed without mentioning where you measure this speed from. An observer passing a train from another train travelling in the opposite direction will measure the other train’s speed as being faster than it should be, since the observer’s train is moving in the other direction as he tries to measure the speed of the other train.
Einstein and other great thinkers at the start of the century performed a series of thought-experiments and showed that this theory means that the Universe effectively has a speed limit. Nothing can travel faster than the speed of light. Scientists at the OPERA experiment at CERN in Switzerland have measured the speed of particles known as muon neutrinos to be faster than the speed of light. These particles are, in a sense, breaking the laws of the Universe.
What people outside of the field want to know is how likely it is that there is an error in the experiment performed at CERN and if not, what effect this would have on areas like Chemistry and Engineering that rely on physics. Certainly having to redo 106 years of work would mean a lot of work for physicists. This is why the discovery that particles travel faster than the speed of light is so huge, if true. If the result can be verified, then scientists will either need to replace the Theory of Relativity with a new one, or else come up with a new theory of particle physics that would explain why this certain type of particle is an exception to the rule.
The scientists at CERN have taken multiple steps to reduce the error in their experiment. This includes taking the curvature of the Earth into account when measuring lengths and an upgrade of the timing system in place at the detector. Scientists have statistical methods to find out how unlikely an event is to happen if they assume a theory. The result in this case was exceptionally improbable. In fact, such a result would be considered in the realms of impossible by people in other fields that use statistics in this way.
What this all means is that it seems that the result is genuine, unless there was some error in how the experiment was carried out. The group at CERN refused to speculate on what the outcome of their experiment might mean. “Despite the large significance of the measurement reported here and the stability of the analysis, the potentially great impact of the result motivates the continuation of our studies in order to investigate possible still unknown systematic effects that could explain the observed anomaly.”
It will be known whether there was a mistake in their method if the result can be independently checked by another group. Scientists at the MINOS experiment in America first flagged the possibility of neutrinos travelling faster than the speed of light in 2007 and will now try to upgrade their experiment to try to test this result.
One thing is certain; the physics community will be holding its breath.