A few days ago, I was reminiscing about my past, particularly my undergraduate days at Hindu College. It was 2011, my second year in college. I did not so much relish sitting in the class due to monotonous lectures and age-old pedagogy employed by the Professors as much as I enjoyed spending time in the library, or sitting in the canteen, or sitting under the shade of V-Tree and discussing radical entrepreneurial ideas with a close friend or simply just loitering around in the humongous ground of Hindu College.
23rd September 2011, a Friday morning. The lecture was on Mathematical Physics and as usual, I wasn’t enjoying it. I took out my Blackberry from my pocket and started browsing Facebook. Then all of a sudden, I came across an article with the caption,
“An international team of scientists says it has recorded sub-atomic particles traveling faster than light — a finding that could overturn one of Albert Einstein’s long-accepted fundamental laws of the universe.”
I was stunned reading it. My first reaction was the experiment-would-be-wrong, it has to be wrong. But it changed quickly. I was amazed hoping it was true and subatomic particles could indeed travel faster than light. It was a breakthrough for physicists across the world. It meant we are back in the 16th century and the Modern Physics is no more Modern, it needs some changes or at least ways to fix it.
The celebrity particles in the conversation were Neutrinos. Neutrinos are tiny elementary particles having negligible mass. Millions of Neutrinos arriving from space, mainly from the sun strike our body and pass through it. There are 3 types of neutrinos — electron neutrinos, muon neutrinos and tau neutrinos. The most common of them are electron neutrinos, which are produced by beta decay inside the nuclei of atoms. Neutrinos have fingerful mass and are considered featherweights of the subatomic world, and they can travel almost at the speed of light.
The experiment which gave Neutrinos their short-lived celebrity status was conducted by CERN called Opera Neutrino Experiment. The experiment was conducted on Muon Neutrinos where they calculated the time the neutrinos took to travel from their point of origin at CERN in Geneva to the Grand Sasso Lab in Italy. The travel distance was 730 kilometers and the neutrinos appeared to be able to cover this at a speed faster than that of Light. (Light would have covered the same distance in around 2.4 thousandths of a second, but the neutrinos took 60 nanoseconds or — 60 billionths of a second — less than light beams would have taken.)
Einstein in his Special Theory of Relativity asserted that nothing can travel faster than light. Laws of Nature, at least until that point in time, were formulated in a way that forbade anything from going faster. The Universe, of course, does not have any special affection toward Light, allowing it to hold this grand speed record. It is rather the way space and time themselves are intertwined in our universe that implies there is a maximum speed limit beyond which the laws of Physics break down. This speed happens to be 299792458 m/s in our universe. Light because it has no mass, can travel at this speed.
Imagine a vehicle moving extremely fast and reaching the speed of light and we are providing even more energy to it, trying to get it faster but it is still bumping against the speed of light (because nothing in this universe can travel faster than light). So where does all this Energy goes? It goes into the mass of an object. The vehicle actually gets heavier. The most important consequence of the equations of special relativity is how energy and mass are related. In his miracle year 1905, Einstein showed that mass can be converted into energy and vice-versa through his equation, E=mc². It is one of the world’s most famous, simple, and powerful equations. E=mc² gives a unique definition of the matter. Matter can be defined as nothing but the condensation of a vast amount of energy.
But could Einstein have been wrong? And if he is wrong, then what about the experiments which proved Relativity Theory correct? If the Opera experiment conducted is without any error, (they were apparently getting the same result for 3 years even after repeating it multiple times) then why does no other neutrino experiment shows such a result?
I had these questions in my mind while sitting in the class and not paying any attention. I was excited to discuss this with my close friend as soon as the class gets over. But the class felt infinitely longer. And I can use the word infinitely casually because Modern Physics was crumbling and nothing was apparent. The class finally got over and I rushed to discuss the gallimaufry state of Physics with the friend.
I made him read the news article and his expression was similar to mine. The experiment is wrong, it has to be wrong. The universe has no place for such radical changes. This was an ineffaceable belief in our subconscious minds and our conscious minds were not ready to accept the results of this experiment. While we had this conviction, we started to read what other, more reputable, Physicists had to say on this.
Some Physicists already published their theory. Some were in favor while others refuted it. Yet, there was no unanimous consensus. Nobel Prize winner, Sheldon Glashow predicted that such faster-than-light particles would have to be radiating electrons and their anti-particle positron all along their journey from Geneva to Italy via a process called Vacuum Cerenkov Radiation and hence, lose energy. Some Physicists with the help of String Theory predicted that neutrinos while traveling take a distinct dimension and therefore they take a shortcut or they cover a distance lesser than the actual length and hence the time taken by them is less as compared to light beam because light particles are not being observed showing any such phenomenon.
It was all predictions and theories. But we were dead confident about our conviction. Faster-than-light particles meant that the theory of Special Relativity is no more valid which seemed a little far-fetched. There are numerous applications of Special Relativity, one of them is the Global Positioning System (GPS) which is widely used all over the world. GPS works because the Theory of Relativity works and so do the other applications of Relativity.
We eventually returned to my flat. Forgot about the article and went back to playing FIFA. Physicists all over the world might be in a state of quandary seeing Modern Physics crumble right in front of their eyes, while we were more worried about hiding our joystick controllers from each other while taking penalty kicks to decide the fate of our FIFA match.
A couple of months later on 22 February 2012, while still playing FIFA, my phone buzzed with the notification,
“Faster-Than-Light Neutrino Results May Be Due to Bad Cables:
The sensational result that neutrinos can travel faster than the speed of light may be undone by nothing more than a simple mechanical error.”
We looked at each other hubristically and said, Meh! and went back to playing FIFA.
