Friday, September 23, 2011

Neutrinos faster than light???

I've thought a lot about the CERN result that the neutrinos in the OPERA experiment travel slightly faster than the speed of light. This result is truly earth-shattering. A result is a result--first we have to see if there are any holes in it. The press reports say it is sound.

Here is what I know.

They see that the distance between CERN and the experiment in Italy is about 60 feet shorter, out of about 2.4 million feet (730 km) (or one part in 40,000), for neutrinos than what they measure it to be. (The result is that the neutrinos get there 60 nanoseconds early--I translated this into something more understandable). Their error-bars are 10 nanoseconds, which makes this a 6-sigma effect--quite believable.

The speed of light "speed limit" is not something to giggle at. A huge percentage of the understanding we have in the physical world would be toppled if this result is real.

Einstein came up with the "speed limit" after examining Lorentz's observation of the symmetries of the equations of electromagnetism (Maxwell's equations). Lorentz's work was in the 19th century. The constancy of the speed of light, and the inability of an object with mass to obtain the speed of light, is a consequence of the validity of the theories of electricity and magnetism. The fact that we are communicating by electronic computer is a pretty good testament to the validity of our understanding of E&M. Making Lortentz's equations invalid would mean that our understanding of E&M is wrong.

We measure the "speed limit" at Fermilab (and at CERN) every day. I could go on and on about this.

The normalized speed of a particle, beta, is equal to the square-root of (one minus the (the mass-squared over the energy-squared)). For beta to be greater than one would require an "imaginary" energy or mass (but not both). This is the definition of the hypothetical "tachion". An imaginary mass for the neutrino would be very interesting!

So, there are a few possible explanations for this results that I can think of, in order of plausibility (IMHO):
  1. The result is wrong, and there are several ways to satisfy this explanation.
  2. A neutrino has imaginary mass.
  3. There is some time/space/dimensional anomaly between CERN and the experiment, making the distance slightly shorter than it should be.
  4. Our understanding of physics is wrong
(Imaginary energy is what is required to create a stable wormhole, by the way.)

How could the result be wrong? We'll see what they have accounted for in their measurement.
  • Measuring the precise distance is very tricky. They are shooting the neutrinos through the earth, so this requires very precise knowledge of the shape of the Earth and the location of the source and the experiment.
  • Measuring the precise time is also very tricky. This, in particular, is what interests me. How do two places that are 730 km apart synchronize their clocks to this level of precision? Can GPS do that? (Of course, GPS technology RELIES on our understanding of E&M and the constancy of the speed of light. Ironic, eh?)
  • Exactly when and where are the neutrinos created? We think we understand the particle beam and its properties, but if this result is correct, then clearly we don't. (Another irony.)
In my lifetime, there have been two other times when there was a result of earth-shattering proportions:
I believe it is accurate to say that both of these were considered to be good experiments, but no one else has been able to verify the results. Thus, the community has considered these results to be flukes.

1 comment:

  1. Thanks for the post! I was just getting ready to ask you about this... as I read an article about it this morning.