Nothing would satisfy my anarchical mind more than to see the Special Theory of Relativity (SR) come tumbling down. In fact, I believe that there are compelling reasons to consider SR inaccurate, if not actually wrong, although the physics community would have none of that. I will list my misgivings vis-a-vis SR and present my case against it as the last post in this series, but in this one, I would like to explore why it is so difficult to toss SR out the window.

The special theory of relativity is an extremely well-tested theory. Despite my personal reservations about it, the body of proof for the validity of SR is really enormous and the theory has stood the test of time — at least so far. But it is the integration of SR into the rest of modern physics that makes it all but impossible to write it off as a failed theory. In experimental high energy physics, for instance, we compute the rest mass of a particle as its identifying statistical signature. The way it works is this: in order to discover a heavy particle, you first detect its daughter particles (decay products, that is), measure their energies and momenta, add them up (as “4-vectors”), and compute the invariant mass of the system as the modulus of the aggregate energy-momentum vector. In accordance with SR, the invariant mass is the rest mass of the parent particle. You do this for many thousands of times and make a distribution (a “histogram”) and detect any statistically significant excess at any mass. Such an excess is the signature of the parent particle at that mass.

Almost every one of the particles in the particle data book that we know and love is detected using some variant of this method. So the whole Standard Model of particle physics is built on SR. In fact, almost all of modern physics (physics of the 20th century) is built on it. On the theory side, in the thirties, Dirac derived a framework to describe electrons. It combined SR and quantum mechanics in an elegant framework and predicted the existence of positrons, which bore out later on. Although considered incomplete because of its lack of sound physical backdrop, this “second quantization” and its subsequent experimental verification can be rightly seen as evidence for the rightness of SR.

Feynman took it further and completed the quantum electrodynamics (QED), which has been the most rigorously tested theory ever. To digress a bit, Feynman was once being shown around at CERN, and the guide (probably a prominent physicist himself) was explaining the experiments, their objectives etc. Then the guide suddenly remembered who he was talking to; after all, most of the CERN experiments were based on Feynman’s QED. Embarrassed, he said, “Of course, Dr. Feynman, you know all this. These are all to verify your predictions.” Feynman quipped, “Why, you don’t trust me?!” To get back to my point and reiterate it, the whole edifice of the standard model of particle physics is built on top of SR. Its success alone is enough to make it impossible for modern physics to discard SR.

So, if you take away SR, you don’t have the Standard Model and QED, and you don’t know how accelerator experiments and nuclear bombs work. The fact that they do is proof enough for the validity of SR, because the alternative (that we managed to build all these things without really knowing how they work) is just too weird. It’s not just the exotic (nuclear weaponry and CERN experiments), but the mundane that should convince us. Fluorescent lighting, laser pointers, LED, computers, mobile phones, GPS navigators, iPads — in short, all of modern technology is, in some way, a confirmation of SR.

So the OPERA result on observed superluminalily has to be wrong. But I would like it to be right. And I will explain why in my next post. Why everything we accept as a verification of SR could be a case of mass delusion — almost literally. Stay tuned!