Friday, January 6, 2012

Some fundamental changes coming our way?

I like to say (paraphrasing Richard Feynman) that science is always wrong. It's more memorable than saying science is never completely correct. Sometimes this is demonstrated dramatically as when neutrinos are measured traveling faster than the speed of light. Whether these measurements will stand up is still in question, but here is a well written, well reasoned article on the repercussions of OPERA's Gran Sasso neutrino experiment. Scientists realize we have gathered a lot of truth about the world. Let's not throw that out, but we may have to tweak it a bit.

However, says Chris Lee the author of the article, two papers, which assume the data from OPERA is correct, go on to conclude that fundamental and far reaching changes would have to be made to how we understand nature—perhaps even as deep as throwing out the law of conservation of energy and momentum. That doesn't sound like a tweak. Lee seems to be saying that OPERA's results can not be accepted by science at this time. It is just too big a leap. Anyway, the article seems pretty good.

Edit: Science, like the rest of life, is quite humorous. It was Pauli and his emphasis on the conservation of energy and momentum that led to his prediction that neutrinos exist in the first place!

3 comments:

James R said...

Here's a comment to the original article. (I love to read comments on scientific articles.) It refers to previous commenters, but I think you still will get a good grasp of what the commenter is saying.

JAlfredPrufrock | about 6 hours ago | permalink
Just a few quick points at random:

1. The article is a great summary. Nice job, Chris.

2. For all those proposing wormholes and etc... remember that your results have to square with the rest of observed physics. This is the hard problem.

3. When someone is looking for compatibility with the Standard Model... this is a Very Good Thing®. The Standard Model is wildly successful and accurate – one of the most successful theories that has ever come out of science. It has relatively few external parameters that have to be put in from measurement. Any proposed extension of it needs to be fully compatible with it. Being conservative here is not a bad thing at all.

4. c is the maximum speed because it is. The problem with massive particles moving faster than c is that the gamma factor approaches infinity as the velocity approaches c, and becomes undefined (div/0) at c. This means that a neutrino, no matter how small its mass at the outset, will have an infinite relativistic mass at c. This mass comes from its relativistic momentum, which increases (E^2 = p^2c^2 + m^2c^4) with the velocity. So to have infinite mass, one has consumed energy on the same asymptote. These neutrinos didn't consume infinite energy in accelerating, so... they didn't get ramped up. This is very well established, by the way – special relativity is not in question because we use it every day at CERN.

5. So what if the neutrino is created at a speed above c, so we don't have to worry about ramping up? Then you have to worry about paradoxes that contravene causality. See http://en.wikipedia.org/wiki/Tachyonic_antitelephone. This can also be a violation of conservation of energy, which has been sought for and excluded in detail in many places.

So -- this is a hard problem, because it seems to contradict some fairly impressively established (and constantly reverified) measurements. Which is why most people are looking for experimental errors. Similar "new" results showed up in the Eöt-Walsh torsion-pendulum experiments in the late 90s, but were finally traced to a subtle problem in the consistency of a positioning screw -- before publication. This apparatus is much larger and more difficult to debug. Give it time, and the result will go away. Probably.

And if not, there's going to be a heck of a lot to do to explain the really huge contradictions we see.

Big Myk said...

Similar issues arise with the observations of the rotation curves of spiral galaxies. As I understand it, under Newton's analysis, orbiting objects further from a gravitational source must necessarily travel more slowly than objects closer to the gravitational source, as Mercury travels much faster around the sun than earth. Otherwise, the objects further out will break free of the gravitational pull.

However, as Vera Rubin discovered, when measuring galactic rotation, rotation curves remain flat (or almost constant) regardless of their distance from the galactic center.

So, either Newton has to be modified, or there is a lot of matter out there we don't know about holding these galaxies together. Most scientists don't want to mess with Newton, and so have invented "dark matter" which cannot be observed because it does not interact with conventional matter. Other scientists, including Rubin, have adopted MOND (for Modified Newtonian Dynamics).

It's the difficult question of how long do we hold onto time-honored models of the universe, and when is it time to look for something new.

Big Myk said...

Oh yes, and on the same topic of "science is always wrong," I get really tired of all the cynicism we always hear about how medical advice keeps changing -- as if this is evidence that medical community has no idea what it is doing, or the whole thing is some kind of scam.

Of course, as we learn more, medical advice keeps changing! I'd begin to question the value of medicine if the advice stopped changing.